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rustdoc::broken_intra_doc_links behavior change with macro_rules not in scope since 1.63 #106142

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ojeda opened this issue Dec 25, 2022 · 4 comments
Labels
A-intra-doc-links Area: Intra-doc links, the ability to link to items in docs by name A-macros Area: All kinds of macros (custom derive, macro_rules!, proc macros, ..) C-bug Category: This is a bug. T-rustdoc Relevant to the rustdoc team, which will review and decide on the PR/issue.

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@ojeda
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Contributor

ojeda commented Dec 25, 2022

rustdoc >= 1.63 complains about this intra-doc link:

pub mod a {
    /// [`m`]
    pub fn f() {}

    #[macro_export]
    macro_rules! m {
        () => {};
    }
}

with:

warning: unresolved link to `m`
 --> c.rs:2:11
  |
2 |     /// [`m`]
  |           ^ no item named `m` in scope
  |
  = note: `macro_rules` named `m` exists in this crate, but it is not in scope at this link's location
  = note: `#[warn(rustdoc::broken_intra_doc_links)]` on by default

warning: 1 warning emitted

However, the link is still generated in the rendered output, and points to the right place. Thus the text "unresolved link" is a bit confusing, especially since in earlier versions (<= 1.62), there was no warning for this case (and the link still got generated too).

With e.g. crate::m, the warning goes away.

Therefore, if the intended behavior is that the user writes something like crate::m, then when the user just wrote m the link should not be generated (which would make the text of the lint consistent) or the link could be generated but then the warning should say the link may still be generated.

On the other hand, if the intended behavior is that m still works as-is like in previous versions, then it is a false positive and a regression on the lint.

@ojeda ojeda added the C-bug Category: This is a bug. label Dec 25, 2022
@petrochenkov
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Duplicate of #98804.

Despite the warning, the generated link does work as expected.

This is a compatibility measure to keep stuff on docs.rs working if possible.

We can probably remove the compatibility case at this point.

@ojeda
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ojeda commented Dec 25, 2022

Thanks Vadim, indeed it is that one.

We can probably remove the compatibility case at this point.

Sounds great.

@ojeda
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ojeda commented Dec 25, 2022

By the way, do you want to reuse this issue for the removal? (assuming there is not one already)

Kaz205 pushed a commit to Kaz205/linux that referenced this issue Jan 1, 2023
…nings

Since Rust 1.63.0, `rustdoc` complains with `broken_intra_doc_links`
about intra-doc links pointing to exported `macro_rules`, e.g.:

    error: unresolved link to `dev_info`
       --> rust/kernel/device.rs:135:43
        |
    135 |     /// More details are available from [`dev_info`].
        |                                           ^^^^^^^^ no item named `dev_info` in scope
        |
        = note: `macro_rules` named `dev_info` exists in this crate, but it is not in scope at this link's location
        = note: `-D rustdoc::broken-intra-doc-links` implied by `-D warnings`

    error: aborting due to previous error

The text is confusing, because the link still gets generated, and previous versions
(<= 1.62) did not warn and also generated the link. This was reported
upstream at [1], and it turns out that the link still being generated was
a compatibility measure for docs.rs, which may get removed soon. Thus
the intended behavior is that the user specifies the proper path.

Therefore, clean up the `allow()`s introduced earlier to satisfy `rustdoc`
and the new behavior.

Link: rust-lang/rust#106142 [1]
Reviewed-by: Björn Roy Baron <bjorn3_gh@protonmail.com>
Reviewed-by: Martin Rodriguez Reboredo <yakoyoku@gmail.com>
Tested-by: Martin Rodriguez Reboredo <yakoyoku@gmail.com>
Reviewed-by: Gary Guo <gary@garyguo.net>
Reviewed-by: Vincenzo Palazzo <vincenzopalazzodev@gmail.com>
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
Kaz205 pushed a commit to Kaz205/linux that referenced this issue Jan 5, 2023
…nings

Since Rust 1.63.0, `rustdoc` complains with `broken_intra_doc_links`
about intra-doc links pointing to exported `macro_rules`, e.g.:

    error: unresolved link to `dev_info`
       --> rust/kernel/device.rs:135:43
        |
    135 |     /// More details are available from [`dev_info`].
        |                                           ^^^^^^^^ no item named `dev_info` in scope
        |
        = note: `macro_rules` named `dev_info` exists in this crate, but it is not in scope at this link's location
        = note: `-D rustdoc::broken-intra-doc-links` implied by `-D warnings`

    error: aborting due to previous error

The text is confusing, because the link still gets generated, and previous versions
(<= 1.62) did not warn and also generated the link. This was reported
upstream at [1], and it turns out that the link still being generated was
a compatibility measure for docs.rs, which may get removed soon. Thus
the intended behavior is that the user specifies the proper path.

Therefore, clean up the `allow()`s introduced earlier to satisfy `rustdoc`
and the new behavior.

Link: rust-lang/rust#106142 [1]
Reviewed-by: Björn Roy Baron <bjorn3_gh@protonmail.com>
Reviewed-by: Martin Rodriguez Reboredo <yakoyoku@gmail.com>
Tested-by: Martin Rodriguez Reboredo <yakoyoku@gmail.com>
Reviewed-by: Gary Guo <gary@garyguo.net>
Reviewed-by: Vincenzo Palazzo <vincenzopalazzodev@gmail.com>
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
Kaz205 pushed a commit to Kaz205/linux that referenced this issue Jan 5, 2023
…nings

Since Rust 1.63.0, `rustdoc` complains with `broken_intra_doc_links`
about intra-doc links pointing to exported `macro_rules`, e.g.:

    error: unresolved link to `dev_info`
       --> rust/kernel/device.rs:135:43
        |
    135 |     /// More details are available from [`dev_info`].
        |                                           ^^^^^^^^ no item named `dev_info` in scope
        |
        = note: `macro_rules` named `dev_info` exists in this crate, but it is not in scope at this link's location
        = note: `-D rustdoc::broken-intra-doc-links` implied by `-D warnings`

    error: aborting due to previous error

The text is confusing, because the link still gets generated, and previous versions
(<= 1.62) did not warn and also generated the link. This was reported
upstream at [1], and it turns out that the link still being generated was
a compatibility measure for docs.rs, which may get removed soon. Thus
the intended behavior is that the user specifies the proper path.

Therefore, clean up the `allow()`s introduced earlier to satisfy `rustdoc`
and the new behavior.

Link: rust-lang/rust#106142 [1]
Reviewed-by: Björn Roy Baron <bjorn3_gh@protonmail.com>
Reviewed-by: Martin Rodriguez Reboredo <yakoyoku@gmail.com>
Tested-by: Martin Rodriguez Reboredo <yakoyoku@gmail.com>
Reviewed-by: Gary Guo <gary@garyguo.net>
Reviewed-by: Vincenzo Palazzo <vincenzopalazzodev@gmail.com>
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
Kaz205 pushed a commit to Kaz205/linux that referenced this issue Jan 11, 2023
…nings

Since Rust 1.63.0, `rustdoc` complains with `broken_intra_doc_links`
about intra-doc links pointing to exported `macro_rules`, e.g.:

    error: unresolved link to `dev_info`
       --> rust/kernel/device.rs:135:43
        |
    135 |     /// More details are available from [`dev_info`].
        |                                           ^^^^^^^^ no item named `dev_info` in scope
        |
        = note: `macro_rules` named `dev_info` exists in this crate, but it is not in scope at this link's location
        = note: `-D rustdoc::broken-intra-doc-links` implied by `-D warnings`

    error: aborting due to previous error

The text is confusing, because the link still gets generated, and previous versions
(<= 1.62) did not warn and also generated the link. This was reported
upstream at [1], and it turns out that the link still being generated was
a compatibility measure for docs.rs, which may get removed soon. Thus
the intended behavior is that the user specifies the proper path.

Therefore, clean up the `allow()`s introduced earlier to satisfy `rustdoc`
and the new behavior.

Link: rust-lang/rust#106142 [1]
Reviewed-by: Björn Roy Baron <bjorn3_gh@protonmail.com>
Reviewed-by: Martin Rodriguez Reboredo <yakoyoku@gmail.com>
Tested-by: Martin Rodriguez Reboredo <yakoyoku@gmail.com>
Reviewed-by: Gary Guo <gary@garyguo.net>
Reviewed-by: Vincenzo Palazzo <vincenzopalazzodev@gmail.com>
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
y86-dev pushed a commit to y86-dev/linux that referenced this issue Jan 11, 2023
Upgrade the Rust version from 1.62.0 to 1.66.0.

The overwhelming majority of the commit is about upgrading our `alloc`
fork to the new version from upstream [1]. License has not changed [2][3]
(there were changes in the `COPYRIGHT` file, but unrelated to `alloc`).

As in the previous version upgrades (done out of tree so far), upgrading
`alloc` requires checking that our small additions (`try_*`) still match
their original (non`-try_*`) versions.

With this version upgrade, the following unstable Rust features were
stabilized: `bench_black_box` (1.66.0), `const_ptr_offset_from` (1.65.0),
`core_ffi_c` (1.64.0) and `generic_associated_types` (1.65.0). Thus
remove them.

This also implies that only two unstable features remain allowed for
non-`rust/` code: `allocator_api` and `const_refs_to_cell`.

There are some new Clippy warnings that we are triggering (i.e.
introduced since 1.62.0), as well as a few others that were not
triggered before, thus allow them in this commit and clean up or
remove them as needed later on:

  - `borrow_deref_ref` (new in 1.63.0).
  - `explicit_auto_deref` (new in 1.64.0).
  - `bool_to_int_with_if` (new in 1.65.0).
  - `needless_borrow`.
  - `type_complexity`.
  - `unnecessary_cast` (allowed only on `CONFIG_ARM`).

Furthermore, `rustdoc` lint `broken_intra_doc_links` is triggering on
links pointing to `macro_export` `macro_rules` defined in the same
module (i.e. appearing in the crate root).

However, even if the warning appears, the link still gets generated
like in previous versions, thus it is a bit confusing. An issue has
been opened upstream [4], and it appears that the link still being
generated was a compatibility measure, thus we will need to adapt
to the new behavior (done in the next patch).

In addition, there is an added `#[const_trait]` attribute in
`RawDeviceId`, due to 1.66.0's PR "Require `#[const_trait]` on `Trait`
for `impl const Trait`") [5].

Finally, the `-Aunused-imports` was added for compiling `core`. This was
fixed upstream for 1.67.0 in PR "Fix warning when libcore is compiled
with no_fp_fmt_parse" [6], and prevented for the future for that `cfg`
in PR "core: ensure `no_fp_fmt_parse builds` are warning-free" [7].

Reviewed-by: Björn Roy Baron <bjorn3_gh@protonmail.com>
Reviewed-by: Martin Rodriguez Reboredo <yakoyoku@gmail.com>
Tested-by: Martin Rodriguez Reboredo <yakoyoku@gmail.com>
Reviewed-by: Gary Guo <gary@garyguo.net>
Reviewed-by: Vincenzo Palazzo <vincenzopalazzodev@gmail.com>
Reviewed-by: Alice Ferrazzi <alice.ferrazzi@miraclelinux.com>
Tested-by: Alice Ferrazzi <alice.ferrazzi@miraclelinux.com>
Reviewed-by: Neal Gompa <neal@gompa.dev>
Tested-by: Neal Gompa <neal@gompa.dev>
Link: Rust-for-Linux#947
Link: https://github.com/rust-lang/rust/tree/1.66.0/library/alloc/src [1]
Link: https://github.com/rust-lang/rust/blob/1.66.0/library/alloc/Cargo.toml#L4 [2]
Link: https://github.com/rust-lang/rust/blob/1.66.0/COPYRIGHT [3]
Link: rust-lang/rust#106142 [4]
Link: rust-lang/rust#100982 [5]
Link: rust-lang/rust#105434 [6]
Link: rust-lang/rust#105811 [7]
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
y86-dev pushed a commit to y86-dev/linux that referenced this issue Jan 11, 2023
…nings

Since Rust 1.63.0, `rustdoc` complains with `broken_intra_doc_links`
about intra-doc links pointing to exported `macro_rules`, e.g.:

    error: unresolved link to `dev_info`
       --> rust/kernel/device.rs:135:43
        |
    135 |     /// More details are available from [`dev_info`].
        |                                           ^^^^^^^^ no item named `dev_info` in scope
        |
        = note: `macro_rules` named `dev_info` exists in this crate, but it is not in scope at this link's location
        = note: `-D rustdoc::broken-intra-doc-links` implied by `-D warnings`

    error: aborting due to previous error

The text is confusing, because the link still gets generated, and previous versions
(<= 1.62) did not warn and also generated the link. This was reported
upstream at [1], and it turns out that the link still being generated was
a compatibility measure for docs.rs, which may get removed soon. Thus
the intended behavior is that the user specifies the proper path.

Therefore, clean up the `allow()`s introduced earlier to satisfy `rustdoc`
and the new behavior.

Link: rust-lang/rust#106142 [1]
Reviewed-by: Björn Roy Baron <bjorn3_gh@protonmail.com>
Reviewed-by: Martin Rodriguez Reboredo <yakoyoku@gmail.com>
Tested-by: Martin Rodriguez Reboredo <yakoyoku@gmail.com>
Reviewed-by: Gary Guo <gary@garyguo.net>
Reviewed-by: Vincenzo Palazzo <vincenzopalazzodev@gmail.com>
Reviewed-by: Alice Ferrazzi <alice.ferrazzi@miraclelinux.com>
Tested-by: Alice Ferrazzi <alice.ferrazzi@miraclelinux.com>
Reviewed-by: Neal Gompa <neal@gompa.dev>
Tested-by: Neal Gompa <neal@gompa.dev>
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
Kaz205 pushed a commit to Kaz205/linux that referenced this issue Jan 17, 2023
…nings

Since Rust 1.63.0, `rustdoc` complains with `broken_intra_doc_links`
about intra-doc links pointing to exported `macro_rules`, e.g.:

    error: unresolved link to `dev_info`
       --> rust/kernel/device.rs:135:43
        |
    135 |     /// More details are available from [`dev_info`].
        |                                           ^^^^^^^^ no item named `dev_info` in scope
        |
        = note: `macro_rules` named `dev_info` exists in this crate, but it is not in scope at this link's location
        = note: `-D rustdoc::broken-intra-doc-links` implied by `-D warnings`

    error: aborting due to previous error

The text is confusing, because the link still gets generated, and previous versions
(<= 1.62) did not warn and also generated the link. This was reported
upstream at [1], and it turns out that the link still being generated was
a compatibility measure for docs.rs, which may get removed soon. Thus
the intended behavior is that the user specifies the proper path.

Therefore, clean up the `allow()`s introduced earlier to satisfy `rustdoc`
and the new behavior.

Link: rust-lang/rust#106142 [1]
Reviewed-by: Björn Roy Baron <bjorn3_gh@protonmail.com>
Reviewed-by: Martin Rodriguez Reboredo <yakoyoku@gmail.com>
Tested-by: Martin Rodriguez Reboredo <yakoyoku@gmail.com>
Reviewed-by: Gary Guo <gary@garyguo.net>
Reviewed-by: Vincenzo Palazzo <vincenzopalazzodev@gmail.com>
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
Kaz205 pushed a commit to Kaz205/linux that referenced this issue Jan 22, 2023
…nings

Since Rust 1.63.0, `rustdoc` complains with `broken_intra_doc_links`
about intra-doc links pointing to exported `macro_rules`, e.g.:

    error: unresolved link to `dev_info`
       --> rust/kernel/device.rs:135:43
        |
    135 |     /// More details are available from [`dev_info`].
        |                                           ^^^^^^^^ no item named `dev_info` in scope
        |
        = note: `macro_rules` named `dev_info` exists in this crate, but it is not in scope at this link's location
        = note: `-D rustdoc::broken-intra-doc-links` implied by `-D warnings`

    error: aborting due to previous error

The text is confusing, because the link still gets generated, and previous versions
(<= 1.62) did not warn and also generated the link. This was reported
upstream at [1], and it turns out that the link still being generated was
a compatibility measure for docs.rs, which may get removed soon. Thus
the intended behavior is that the user specifies the proper path.

Therefore, clean up the `allow()`s introduced earlier to satisfy `rustdoc`
and the new behavior.

Link: rust-lang/rust#106142 [1]
Reviewed-by: Björn Roy Baron <bjorn3_gh@protonmail.com>
Reviewed-by: Martin Rodriguez Reboredo <yakoyoku@gmail.com>
Tested-by: Martin Rodriguez Reboredo <yakoyoku@gmail.com>
Reviewed-by: Gary Guo <gary@garyguo.net>
Reviewed-by: Vincenzo Palazzo <vincenzopalazzodev@gmail.com>
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
Kaz205 pushed a commit to Kaz205/linux that referenced this issue Jan 22, 2023
…nings

Since Rust 1.63.0, `rustdoc` complains with `broken_intra_doc_links`
about intra-doc links pointing to exported `macro_rules`, e.g.:

    error: unresolved link to `dev_info`
       --> rust/kernel/device.rs:135:43
        |
    135 |     /// More details are available from [`dev_info`].
        |                                           ^^^^^^^^ no item named `dev_info` in scope
        |
        = note: `macro_rules` named `dev_info` exists in this crate, but it is not in scope at this link's location
        = note: `-D rustdoc::broken-intra-doc-links` implied by `-D warnings`

    error: aborting due to previous error

The text is confusing, because the link still gets generated, and previous versions
(<= 1.62) did not warn and also generated the link. This was reported
upstream at [1], and it turns out that the link still being generated was
a compatibility measure for docs.rs, which may get removed soon. Thus
the intended behavior is that the user specifies the proper path.

Therefore, clean up the `allow()`s introduced earlier to satisfy `rustdoc`
and the new behavior.

Link: rust-lang/rust#106142 [1]
Reviewed-by: Björn Roy Baron <bjorn3_gh@protonmail.com>
Reviewed-by: Martin Rodriguez Reboredo <yakoyoku@gmail.com>
Tested-by: Martin Rodriguez Reboredo <yakoyoku@gmail.com>
Reviewed-by: Gary Guo <gary@garyguo.net>
Reviewed-by: Vincenzo Palazzo <vincenzopalazzodev@gmail.com>
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
Kaz205 pushed a commit to Kaz205/linux that referenced this issue Jan 22, 2023
…nings

Since Rust 1.63.0, `rustdoc` complains with `broken_intra_doc_links`
about intra-doc links pointing to exported `macro_rules`, e.g.:

    error: unresolved link to `dev_info`
       --> rust/kernel/device.rs:135:43
        |
    135 |     /// More details are available from [`dev_info`].
        |                                           ^^^^^^^^ no item named `dev_info` in scope
        |
        = note: `macro_rules` named `dev_info` exists in this crate, but it is not in scope at this link's location
        = note: `-D rustdoc::broken-intra-doc-links` implied by `-D warnings`

    error: aborting due to previous error

The text is confusing, because the link still gets generated, and previous versions
(<= 1.62) did not warn and also generated the link. This was reported
upstream at [1], and it turns out that the link still being generated was
a compatibility measure for docs.rs, which may get removed soon. Thus
the intended behavior is that the user specifies the proper path.

Therefore, clean up the `allow()`s introduced earlier to satisfy `rustdoc`
and the new behavior.

Link: rust-lang/rust#106142 [1]
Reviewed-by: Björn Roy Baron <bjorn3_gh@protonmail.com>
Reviewed-by: Martin Rodriguez Reboredo <yakoyoku@gmail.com>
Tested-by: Martin Rodriguez Reboredo <yakoyoku@gmail.com>
Reviewed-by: Gary Guo <gary@garyguo.net>
Reviewed-by: Vincenzo Palazzo <vincenzopalazzodev@gmail.com>
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
Kaz205 pushed a commit to Kaz205/linux that referenced this issue Jan 22, 2023
…nings

Since Rust 1.63.0, `rustdoc` complains with `broken_intra_doc_links`
about intra-doc links pointing to exported `macro_rules`, e.g.:

    error: unresolved link to `dev_info`
       --> rust/kernel/device.rs:135:43
        |
    135 |     /// More details are available from [`dev_info`].
        |                                           ^^^^^^^^ no item named `dev_info` in scope
        |
        = note: `macro_rules` named `dev_info` exists in this crate, but it is not in scope at this link's location
        = note: `-D rustdoc::broken-intra-doc-links` implied by `-D warnings`

    error: aborting due to previous error

The text is confusing, because the link still gets generated, and previous versions
(<= 1.62) did not warn and also generated the link. This was reported
upstream at [1], and it turns out that the link still being generated was
a compatibility measure for docs.rs, which may get removed soon. Thus
the intended behavior is that the user specifies the proper path.

Therefore, clean up the `allow()`s introduced earlier to satisfy `rustdoc`
and the new behavior.

Link: rust-lang/rust#106142 [1]
Reviewed-by: Björn Roy Baron <bjorn3_gh@protonmail.com>
Reviewed-by: Martin Rodriguez Reboredo <yakoyoku@gmail.com>
Tested-by: Martin Rodriguez Reboredo <yakoyoku@gmail.com>
Reviewed-by: Gary Guo <gary@garyguo.net>
Reviewed-by: Vincenzo Palazzo <vincenzopalazzodev@gmail.com>
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
Kaz205 pushed a commit to Kaz205/linux that referenced this issue Jan 24, 2023
…nings

Since Rust 1.63.0, `rustdoc` complains with `broken_intra_doc_links`
about intra-doc links pointing to exported `macro_rules`, e.g.:

    error: unresolved link to `dev_info`
       --> rust/kernel/device.rs:135:43
        |
    135 |     /// More details are available from [`dev_info`].
        |                                           ^^^^^^^^ no item named `dev_info` in scope
        |
        = note: `macro_rules` named `dev_info` exists in this crate, but it is not in scope at this link's location
        = note: `-D rustdoc::broken-intra-doc-links` implied by `-D warnings`

    error: aborting due to previous error

The text is confusing, because the link still gets generated, and previous versions
(<= 1.62) did not warn and also generated the link. This was reported
upstream at [1], and it turns out that the link still being generated was
a compatibility measure for docs.rs, which may get removed soon. Thus
the intended behavior is that the user specifies the proper path.

Therefore, clean up the `allow()`s introduced earlier to satisfy `rustdoc`
and the new behavior.

Link: rust-lang/rust#106142 [1]
Reviewed-by: Björn Roy Baron <bjorn3_gh@protonmail.com>
Reviewed-by: Martin Rodriguez Reboredo <yakoyoku@gmail.com>
Tested-by: Martin Rodriguez Reboredo <yakoyoku@gmail.com>
Reviewed-by: Gary Guo <gary@garyguo.net>
Reviewed-by: Vincenzo Palazzo <vincenzopalazzodev@gmail.com>
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
vvarma pushed a commit to vvarma/rusty-linux that referenced this issue Jan 24, 2023
Upgrade the Rust version from 1.62.0 to 1.66.0.

The overwhelming majority of the commit is about upgrading our `alloc`
fork to the new version from upstream [1]. License has not changed [2][3]
(there were changes in the `COPYRIGHT` file, but unrelated to `alloc`).

As in the previous version upgrades (done out of tree so far), upgrading
`alloc` requires checking that our small additions (`try_*`) still match
their original (non`-try_*`) versions.

With this version upgrade, the following unstable Rust features were
stabilized: `bench_black_box` (1.66.0), `const_ptr_offset_from` (1.65.0),
`core_ffi_c` (1.64.0) and `generic_associated_types` (1.65.0). Thus
remove them.

This also implies that only two unstable features remain allowed for
non-`rust/` code: `allocator_api` and `const_refs_to_cell`.

There are some new Clippy warnings that we are triggering (i.e.
introduced since 1.62.0), as well as a few others that were not
triggered before, thus allow them in this commit and clean up or
remove them as needed later on:

  - `borrow_deref_ref` (new in 1.63.0).
  - `explicit_auto_deref` (new in 1.64.0).
  - `bool_to_int_with_if` (new in 1.65.0).
  - `needless_borrow`.
  - `type_complexity`.
  - `unnecessary_cast` (allowed only on `CONFIG_ARM`).

Furthermore, `rustdoc` lint `broken_intra_doc_links` is triggering on
links pointing to `macro_export` `macro_rules` defined in the same
module (i.e. appearing in the crate root).

However, even if the warning appears, the link still gets generated
like in previous versions, thus it is a bit confusing. An issue has
been opened upstream [4], and it appears that the link still being
generated was a compatibility measure, thus we will need to adapt
to the new behavior (done in the next patch).

In addition, there is an added `#[const_trait]` attribute in
`RawDeviceId`, due to 1.66.0's PR "Require `#[const_trait]` on `Trait`
for `impl const Trait`") [5].

Finally, the `-Aunused-imports` was added for compiling `core`. This was
fixed upstream for 1.67.0 in PR "Fix warning when libcore is compiled
with no_fp_fmt_parse" [6], and prevented for the future for that `cfg`
in PR "core: ensure `no_fp_fmt_parse builds` are warning-free" [7].

Reviewed-by: Björn Roy Baron <bjorn3_gh@protonmail.com>
Reviewed-by: Martin Rodriguez Reboredo <yakoyoku@gmail.com>
Tested-by: Martin Rodriguez Reboredo <yakoyoku@gmail.com>
Reviewed-by: Gary Guo <gary@garyguo.net>
Reviewed-by: Vincenzo Palazzo <vincenzopalazzodev@gmail.com>
Reviewed-by: Alice Ferrazzi <alice.ferrazzi@miraclelinux.com>
Tested-by: Alice Ferrazzi <alice.ferrazzi@miraclelinux.com>
Reviewed-by: Neal Gompa <neal@gompa.dev>
Tested-by: Neal Gompa <neal@gompa.dev>
Link: Rust-for-Linux#947
Link: https://github.com/rust-lang/rust/tree/1.66.0/library/alloc/src [1]
Link: https://github.com/rust-lang/rust/blob/1.66.0/library/alloc/Cargo.toml#L4 [2]
Link: https://github.com/rust-lang/rust/blob/1.66.0/COPYRIGHT [3]
Link: rust-lang/rust#106142 [4]
Link: rust-lang/rust#100982 [5]
Link: rust-lang/rust#105434 [6]
Link: rust-lang/rust#105811 [7]
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
vvarma pushed a commit to vvarma/rusty-linux that referenced this issue Jan 24, 2023
…nings

Since Rust 1.63.0, `rustdoc` complains with `broken_intra_doc_links`
about intra-doc links pointing to exported `macro_rules`, e.g.:

    error: unresolved link to `dev_info`
       --> rust/kernel/device.rs:135:43
        |
    135 |     /// More details are available from [`dev_info`].
        |                                           ^^^^^^^^ no item named `dev_info` in scope
        |
        = note: `macro_rules` named `dev_info` exists in this crate, but it is not in scope at this link's location
        = note: `-D rustdoc::broken-intra-doc-links` implied by `-D warnings`

    error: aborting due to previous error

The text is confusing, because the link still gets generated, and previous versions
(<= 1.62) did not warn and also generated the link. This was reported
upstream at [1], and it turns out that the link still being generated was
a compatibility measure for docs.rs, which may get removed soon. Thus
the intended behavior is that the user specifies the proper path.

Therefore, clean up the `allow()`s introduced earlier to satisfy `rustdoc`
and the new behavior.

Link: rust-lang/rust#106142 [1]
Reviewed-by: Björn Roy Baron <bjorn3_gh@protonmail.com>
Reviewed-by: Martin Rodriguez Reboredo <yakoyoku@gmail.com>
Tested-by: Martin Rodriguez Reboredo <yakoyoku@gmail.com>
Reviewed-by: Gary Guo <gary@garyguo.net>
Reviewed-by: Vincenzo Palazzo <vincenzopalazzodev@gmail.com>
Reviewed-by: Alice Ferrazzi <alice.ferrazzi@miraclelinux.com>
Tested-by: Alice Ferrazzi <alice.ferrazzi@miraclelinux.com>
Reviewed-by: Neal Gompa <neal@gompa.dev>
Tested-by: Neal Gompa <neal@gompa.dev>
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
asahilina pushed a commit to AsahiLinux/linux that referenced this issue Feb 16, 2023
Upgrade the Rust version from 1.62.0 to 1.66.0.

The overwhelming majority of the commit is about upgrading our `alloc`
fork to the new version from upstream [1]. License has not changed [2][3]
(there were changes in the `COPYRIGHT` file, but unrelated to `alloc`).

As in the previous version upgrades (done out of tree so far), upgrading
`alloc` requires checking that our small additions (`try_*`) still match
their original (non`-try_*`) versions.

With this version upgrade, the following unstable Rust features were
stabilized: `bench_black_box` (1.66.0), `const_ptr_offset_from` (1.65.0),
`core_ffi_c` (1.64.0) and `generic_associated_types` (1.65.0). Thus
remove them.

This also implies that only two unstable features remain allowed for
non-`rust/` code: `allocator_api` and `const_refs_to_cell`.

There are some new Clippy warnings that we are triggering (i.e.
introduced since 1.62.0), as well as a few others that were not
triggered before, thus allow them in this commit and clean up or
remove them as needed later on:

  - `borrow_deref_ref` (new in 1.63.0).
  - `explicit_auto_deref` (new in 1.64.0).
  - `bool_to_int_with_if` (new in 1.65.0).
  - `needless_borrow`.
  - `type_complexity`.
  - `unnecessary_cast` (allowed only on `CONFIG_ARM`).

Furthermore, `rustdoc` lint `broken_intra_doc_links` is triggering on
links pointing to `macro_export` `macro_rules` defined in the same
module (i.e. appearing in the crate root).

However, even if the warning appears, the link still gets generated
like in previous versions, thus it is a bit confusing. An issue has
been opened upstream [4], and it appears that the link still being
generated was a compatibility measure, thus we will need to adapt
to the new behavior (done in the next patch).

In addition, there is an added `#[const_trait]` attribute in
`RawDeviceId`, due to 1.66.0's PR "Require `#[const_trait]` on `Trait`
for `impl const Trait`") [5].

Finally, the `-Aunused-imports` was added for compiling `core`. This was
fixed upstream for 1.67.0 in PR "Fix warning when libcore is compiled
with no_fp_fmt_parse" [6], and prevented for the future for that `cfg`
in PR "core: ensure `no_fp_fmt_parse builds` are warning-free" [7].

Reviewed-by: Björn Roy Baron <bjorn3_gh@protonmail.com>
Reviewed-by: Martin Rodriguez Reboredo <yakoyoku@gmail.com>
Tested-by: Martin Rodriguez Reboredo <yakoyoku@gmail.com>
Reviewed-by: Gary Guo <gary@garyguo.net>
Reviewed-by: Vincenzo Palazzo <vincenzopalazzodev@gmail.com>
Reviewed-by: Alice Ferrazzi <alice.ferrazzi@miraclelinux.com>
Tested-by: Alice Ferrazzi <alice.ferrazzi@miraclelinux.com>
Reviewed-by: Neal Gompa <neal@gompa.dev>
Tested-by: Neal Gompa <neal@gompa.dev>
Link: Rust-for-Linux#947
Link: https://github.com/rust-lang/rust/tree/1.66.0/library/alloc/src [1]
Link: https://github.com/rust-lang/rust/blob/1.66.0/library/alloc/Cargo.toml#L4 [2]
Link: https://github.com/rust-lang/rust/blob/1.66.0/COPYRIGHT [3]
Link: rust-lang/rust#106142 [4]
Link: rust-lang/rust#100982 [5]
Link: rust-lang/rust#105434 [6]
Link: rust-lang/rust#105811 [7]
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
asahilina pushed a commit to AsahiLinux/linux that referenced this issue Feb 16, 2023
Upgrade the Rust version from 1.62.0 to 1.66.0.

The overwhelming majority of the commit is about upgrading our `alloc`
fork to the new version from upstream [1]. License has not changed [2][3]
(there were changes in the `COPYRIGHT` file, but unrelated to `alloc`).

As in the previous version upgrades (done out of tree so far), upgrading
`alloc` requires checking that our small additions (`try_*`) still match
their original (non`-try_*`) versions.

With this version upgrade, the following unstable Rust features were
stabilized: `bench_black_box` (1.66.0), `const_ptr_offset_from` (1.65.0),
`core_ffi_c` (1.64.0) and `generic_associated_types` (1.65.0). Thus
remove them.

This also implies that only two unstable features remain allowed for
non-`rust/` code: `allocator_api` and `const_refs_to_cell`.

There are some new Clippy warnings that we are triggering (i.e.
introduced since 1.62.0), as well as a few others that were not
triggered before, thus allow them in this commit and clean up or
remove them as needed later on:

  - `borrow_deref_ref` (new in 1.63.0).
  - `explicit_auto_deref` (new in 1.64.0).
  - `bool_to_int_with_if` (new in 1.65.0).
  - `needless_borrow`.
  - `type_complexity`.
  - `unnecessary_cast` (allowed only on `CONFIG_ARM`).

Furthermore, `rustdoc` lint `broken_intra_doc_links` is triggering on
links pointing to `macro_export` `macro_rules` defined in the same
module (i.e. appearing in the crate root).

However, even if the warning appears, the link still gets generated
like in previous versions, thus it is a bit confusing. An issue has
been opened upstream [4], and it appears that the link still being
generated was a compatibility measure, thus we will need to adapt
to the new behavior (done in the next patch).

In addition, there is an added `#[const_trait]` attribute in
`RawDeviceId`, due to 1.66.0's PR "Require `#[const_trait]` on `Trait`
for `impl const Trait`") [5].

Finally, the `-Aunused-imports` was added for compiling `core`. This was
fixed upstream for 1.67.0 in PR "Fix warning when libcore is compiled
with no_fp_fmt_parse" [6], and prevented for the future for that `cfg`
in PR "core: ensure `no_fp_fmt_parse builds` are warning-free" [7].

Reviewed-by: Björn Roy Baron <bjorn3_gh@protonmail.com>
Reviewed-by: Martin Rodriguez Reboredo <yakoyoku@gmail.com>
Tested-by: Martin Rodriguez Reboredo <yakoyoku@gmail.com>
Reviewed-by: Gary Guo <gary@garyguo.net>
Reviewed-by: Vincenzo Palazzo <vincenzopalazzodev@gmail.com>
Reviewed-by: Alice Ferrazzi <alice.ferrazzi@miraclelinux.com>
Tested-by: Alice Ferrazzi <alice.ferrazzi@miraclelinux.com>
Reviewed-by: Neal Gompa <neal@gompa.dev>
Tested-by: Neal Gompa <neal@gompa.dev>
Link: Rust-for-Linux#947
Link: https://github.com/rust-lang/rust/tree/1.66.0/library/alloc/src [1]
Link: https://github.com/rust-lang/rust/blob/1.66.0/library/alloc/Cargo.toml#L4 [2]
Link: https://github.com/rust-lang/rust/blob/1.66.0/COPYRIGHT [3]
Link: rust-lang/rust#106142 [4]
Link: rust-lang/rust#100982 [5]
Link: rust-lang/rust#105434 [6]
Link: rust-lang/rust#105811 [7]
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
mairacanal pushed a commit to mairacanal/linux that referenced this issue Mar 2, 2023
Upgrade the Rust version from 1.62.0 to 1.66.0.

The overwhelming majority of the commit is about upgrading our `alloc`
fork to the new version from upstream [1]. License has not changed [2][3]
(there were changes in the `COPYRIGHT` file, but unrelated to `alloc`).

As in the previous version upgrades (done out of tree so far), upgrading
`alloc` requires checking that our small additions (`try_*`) still match
their original (non`-try_*`) versions.

With this version upgrade, the following unstable Rust features were
stabilized: `bench_black_box` (1.66.0), `const_ptr_offset_from` (1.65.0),
`core_ffi_c` (1.64.0) and `generic_associated_types` (1.65.0). Thus
remove them.

This also implies that only two unstable features remain allowed for
non-`rust/` code: `allocator_api` and `const_refs_to_cell`.

There are some new Clippy warnings that we are triggering (i.e.
introduced since 1.62.0), as well as a few others that were not
triggered before, thus allow them in this commit and clean up or
remove them as needed later on:

  - `borrow_deref_ref` (new in 1.63.0).
  - `explicit_auto_deref` (new in 1.64.0).
  - `bool_to_int_with_if` (new in 1.65.0).
  - `needless_borrow`.
  - `type_complexity`.
  - `unnecessary_cast` (allowed only on `CONFIG_ARM`).

Furthermore, `rustdoc` lint `broken_intra_doc_links` is triggering on
links pointing to `macro_export` `macro_rules` defined in the same
module (i.e. appearing in the crate root).

However, even if the warning appears, the link still gets generated
like in previous versions, thus it is a bit confusing. An issue has
been opened upstream [4], and it appears that the link still being
generated was a compatibility measure, thus we will need to adapt
to the new behavior (done in the next patch).

In addition, there is an added `#[const_trait]` attribute in
`RawDeviceId`, due to 1.66.0's PR "Require `#[const_trait]` on `Trait`
for `impl const Trait`") [5].

Finally, the `-Aunused-imports` was added for compiling `core`. This was
fixed upstream for 1.67.0 in PR "Fix warning when libcore is compiled
with no_fp_fmt_parse" [6], and prevented for the future for that `cfg`
in PR "core: ensure `no_fp_fmt_parse builds` are warning-free" [7].

Reviewed-by: Björn Roy Baron <bjorn3_gh@protonmail.com>
Reviewed-by: Martin Rodriguez Reboredo <yakoyoku@gmail.com>
Tested-by: Martin Rodriguez Reboredo <yakoyoku@gmail.com>
Reviewed-by: Gary Guo <gary@garyguo.net>
Reviewed-by: Vincenzo Palazzo <vincenzopalazzodev@gmail.com>
Reviewed-by: Alice Ferrazzi <alice.ferrazzi@miraclelinux.com>
Tested-by: Alice Ferrazzi <alice.ferrazzi@miraclelinux.com>
Reviewed-by: Neal Gompa <neal@gompa.dev>
Tested-by: Neal Gompa <neal@gompa.dev>
Link: Rust-for-Linux#947
Link: https://github.com/rust-lang/rust/tree/1.66.0/library/alloc/src [1]
Link: https://github.com/rust-lang/rust/blob/1.66.0/library/alloc/Cargo.toml#L4 [2]
Link: https://github.com/rust-lang/rust/blob/1.66.0/COPYRIGHT [3]
Link: rust-lang/rust#106142 [4]
Link: rust-lang/rust#100982 [5]
Link: rust-lang/rust#105434 [6]
Link: rust-lang/rust#105811 [7]
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
jannau pushed a commit to jannau/linux that referenced this issue Mar 9, 2023
Upgrade the Rust version from 1.62.0 to 1.66.0.

The overwhelming majority of the commit is about upgrading our `alloc`
fork to the new version from upstream [1]. License has not changed [2][3]
(there were changes in the `COPYRIGHT` file, but unrelated to `alloc`).

As in the previous version upgrades (done out of tree so far), upgrading
`alloc` requires checking that our small additions (`try_*`) still match
their original (non`-try_*`) versions.

With this version upgrade, the following unstable Rust features were
stabilized: `bench_black_box` (1.66.0), `const_ptr_offset_from` (1.65.0),
`core_ffi_c` (1.64.0) and `generic_associated_types` (1.65.0). Thus
remove them.

This also implies that only two unstable features remain allowed for
non-`rust/` code: `allocator_api` and `const_refs_to_cell`.

There are some new Clippy warnings that we are triggering (i.e.
introduced since 1.62.0), as well as a few others that were not
triggered before, thus allow them in this commit and clean up or
remove them as needed later on:

  - `borrow_deref_ref` (new in 1.63.0).
  - `explicit_auto_deref` (new in 1.64.0).
  - `bool_to_int_with_if` (new in 1.65.0).
  - `needless_borrow`.
  - `type_complexity`.
  - `unnecessary_cast` (allowed only on `CONFIG_ARM`).

Furthermore, `rustdoc` lint `broken_intra_doc_links` is triggering on
links pointing to `macro_export` `macro_rules` defined in the same
module (i.e. appearing in the crate root).

However, even if the warning appears, the link still gets generated
like in previous versions, thus it is a bit confusing. An issue has
been opened upstream [4], and it appears that the link still being
generated was a compatibility measure, thus we will need to adapt
to the new behavior (done in the next patch).

In addition, there is an added `#[const_trait]` attribute in
`RawDeviceId`, due to 1.66.0's PR "Require `#[const_trait]` on `Trait`
for `impl const Trait`") [5].

Finally, the `-Aunused-imports` was added for compiling `core`. This was
fixed upstream for 1.67.0 in PR "Fix warning when libcore is compiled
with no_fp_fmt_parse" [6], and prevented for the future for that `cfg`
in PR "core: ensure `no_fp_fmt_parse builds` are warning-free" [7].

Reviewed-by: Björn Roy Baron <bjorn3_gh@protonmail.com>
Reviewed-by: Martin Rodriguez Reboredo <yakoyoku@gmail.com>
Tested-by: Martin Rodriguez Reboredo <yakoyoku@gmail.com>
Reviewed-by: Gary Guo <gary@garyguo.net>
Reviewed-by: Vincenzo Palazzo <vincenzopalazzodev@gmail.com>
Reviewed-by: Alice Ferrazzi <alice.ferrazzi@miraclelinux.com>
Tested-by: Alice Ferrazzi <alice.ferrazzi@miraclelinux.com>
Reviewed-by: Neal Gompa <neal@gompa.dev>
Tested-by: Neal Gompa <neal@gompa.dev>
Link: Rust-for-Linux#947
Link: https://github.com/rust-lang/rust/tree/1.66.0/library/alloc/src [1]
Link: https://github.com/rust-lang/rust/blob/1.66.0/library/alloc/Cargo.toml#L4 [2]
Link: https://github.com/rust-lang/rust/blob/1.66.0/COPYRIGHT [3]
Link: rust-lang/rust#106142 [4]
Link: rust-lang/rust#100982 [5]
Link: rust-lang/rust#105434 [6]
Link: rust-lang/rust#105811 [7]
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
jannau pushed a commit to jannau/linux that referenced this issue Mar 28, 2023
Upgrade the Rust version from 1.62.0 to 1.66.0.

The overwhelming majority of the commit is about upgrading our `alloc`
fork to the new version from upstream [1]. License has not changed [2][3]
(there were changes in the `COPYRIGHT` file, but unrelated to `alloc`).

As in the previous version upgrades (done out of tree so far), upgrading
`alloc` requires checking that our small additions (`try_*`) still match
their original (non`-try_*`) versions.

With this version upgrade, the following unstable Rust features were
stabilized: `bench_black_box` (1.66.0), `const_ptr_offset_from` (1.65.0),
`core_ffi_c` (1.64.0) and `generic_associated_types` (1.65.0). Thus
remove them.

This also implies that only two unstable features remain allowed for
non-`rust/` code: `allocator_api` and `const_refs_to_cell`.

There are some new Clippy warnings that we are triggering (i.e.
introduced since 1.62.0), as well as a few others that were not
triggered before, thus allow them in this commit and clean up or
remove them as needed later on:

  - `borrow_deref_ref` (new in 1.63.0).
  - `explicit_auto_deref` (new in 1.64.0).
  - `bool_to_int_with_if` (new in 1.65.0).
  - `needless_borrow`.
  - `type_complexity`.
  - `unnecessary_cast` (allowed only on `CONFIG_ARM`).

Furthermore, `rustdoc` lint `broken_intra_doc_links` is triggering on
links pointing to `macro_export` `macro_rules` defined in the same
module (i.e. appearing in the crate root).

However, even if the warning appears, the link still gets generated
like in previous versions, thus it is a bit confusing. An issue has
been opened upstream [4], and it appears that the link still being
generated was a compatibility measure, thus we will need to adapt
to the new behavior (done in the next patch).

In addition, there is an added `#[const_trait]` attribute in
`RawDeviceId`, due to 1.66.0's PR "Require `#[const_trait]` on `Trait`
for `impl const Trait`") [5].

Finally, the `-Aunused-imports` was added for compiling `core`. This was
fixed upstream for 1.67.0 in PR "Fix warning when libcore is compiled
with no_fp_fmt_parse" [6], and prevented for the future for that `cfg`
in PR "core: ensure `no_fp_fmt_parse builds` are warning-free" [7].

Reviewed-by: Björn Roy Baron <bjorn3_gh@protonmail.com>
Reviewed-by: Martin Rodriguez Reboredo <yakoyoku@gmail.com>
Tested-by: Martin Rodriguez Reboredo <yakoyoku@gmail.com>
Reviewed-by: Gary Guo <gary@garyguo.net>
Reviewed-by: Vincenzo Palazzo <vincenzopalazzodev@gmail.com>
Reviewed-by: Alice Ferrazzi <alice.ferrazzi@miraclelinux.com>
Tested-by: Alice Ferrazzi <alice.ferrazzi@miraclelinux.com>
Reviewed-by: Neal Gompa <neal@gompa.dev>
Tested-by: Neal Gompa <neal@gompa.dev>
Link: Rust-for-Linux#947
Link: https://github.com/rust-lang/rust/tree/1.66.0/library/alloc/src [1]
Link: https://github.com/rust-lang/rust/blob/1.66.0/library/alloc/Cargo.toml#L4 [2]
Link: https://github.com/rust-lang/rust/blob/1.66.0/COPYRIGHT [3]
Link: rust-lang/rust#106142 [4]
Link: rust-lang/rust#100982 [5]
Link: rust-lang/rust#105434 [6]
Link: rust-lang/rust#105811 [7]
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
eaxeax pushed a commit to eaxeax/asahi-linux-pf that referenced this issue Apr 10, 2023
Upgrade the Rust version from 1.62.0 to 1.66.0.

The overwhelming majority of the commit is about upgrading our `alloc`
fork to the new version from upstream [1]. License has not changed [2][3]
(there were changes in the `COPYRIGHT` file, but unrelated to `alloc`).

As in the previous version upgrades (done out of tree so far), upgrading
`alloc` requires checking that our small additions (`try_*`) still match
their original (non`-try_*`) versions.

With this version upgrade, the following unstable Rust features were
stabilized: `bench_black_box` (1.66.0), `const_ptr_offset_from` (1.65.0),
`core_ffi_c` (1.64.0) and `generic_associated_types` (1.65.0). Thus
remove them.

This also implies that only two unstable features remain allowed for
non-`rust/` code: `allocator_api` and `const_refs_to_cell`.

There are some new Clippy warnings that we are triggering (i.e.
introduced since 1.62.0), as well as a few others that were not
triggered before, thus allow them in this commit and clean up or
remove them as needed later on:

  - `borrow_deref_ref` (new in 1.63.0).
  - `explicit_auto_deref` (new in 1.64.0).
  - `bool_to_int_with_if` (new in 1.65.0).
  - `needless_borrow`.
  - `type_complexity`.
  - `unnecessary_cast` (allowed only on `CONFIG_ARM`).

Furthermore, `rustdoc` lint `broken_intra_doc_links` is triggering on
links pointing to `macro_export` `macro_rules` defined in the same
module (i.e. appearing in the crate root).

However, even if the warning appears, the link still gets generated
like in previous versions, thus it is a bit confusing. An issue has
been opened upstream [4], and it appears that the link still being
generated was a compatibility measure, thus we will need to adapt
to the new behavior (done in the next patch).

In addition, there is an added `#[const_trait]` attribute in
`RawDeviceId`, due to 1.66.0's PR "Require `#[const_trait]` on `Trait`
for `impl const Trait`") [5].

Finally, the `-Aunused-imports` was added for compiling `core`. This was
fixed upstream for 1.67.0 in PR "Fix warning when libcore is compiled
with no_fp_fmt_parse" [6], and prevented for the future for that `cfg`
in PR "core: ensure `no_fp_fmt_parse builds` are warning-free" [7].

Reviewed-by: Björn Roy Baron <bjorn3_gh@protonmail.com>
Reviewed-by: Martin Rodriguez Reboredo <yakoyoku@gmail.com>
Tested-by: Martin Rodriguez Reboredo <yakoyoku@gmail.com>
Reviewed-by: Gary Guo <gary@garyguo.net>
Reviewed-by: Vincenzo Palazzo <vincenzopalazzodev@gmail.com>
Reviewed-by: Alice Ferrazzi <alice.ferrazzi@miraclelinux.com>
Tested-by: Alice Ferrazzi <alice.ferrazzi@miraclelinux.com>
Reviewed-by: Neal Gompa <neal@gompa.dev>
Tested-by: Neal Gompa <neal@gompa.dev>
Link: Rust-for-Linux#947
Link: https://github.com/rust-lang/rust/tree/1.66.0/library/alloc/src [1]
Link: https://github.com/rust-lang/rust/blob/1.66.0/library/alloc/Cargo.toml#L4 [2]
Link: https://github.com/rust-lang/rust/blob/1.66.0/COPYRIGHT [3]
Link: rust-lang/rust#106142 [4]
Link: rust-lang/rust#100982 [5]
Link: rust-lang/rust#105434 [6]
Link: rust-lang/rust#105811 [7]
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
intel-lab-lkp pushed a commit to intel-lab-lkp/linux that referenced this issue Apr 18, 2023
`Arc<T>::init` refers to `Arc<T>::pin_init` via an intra-doc link
using the text `pin_init`, rather than more explicitly, which makes
`rustdoc` point it to the `pin_init!` macro instead.

This is required for the compiler upgrade since the newer `rustdoc`
would trigger the `broken_intra_doc_links` lint [1], but in this case
the macro was not the intended target to begin with, and so the actual
fix is to make it point to the right place, regardless of the upgrade.

Thus make it more explicit.

Fixes: 92c4a1e ("rust: init/sync: add `InPlaceInit` trait to pin-initialize smart pointers")
Link: rust-lang/rust#106142 [1]
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
intel-lab-lkp pushed a commit to intel-lab-lkp/linux that referenced this issue Apr 18, 2023
This is the first upgrade to the Rust toolchain since the initial Rust
merge, from 1.62.0 to 1.68.2 (i.e. the latest).

# Context

The kernel currently supports only a single Rust version [1] (rather
than a minimum) given our usage of some "unstable" Rust features [2]
which do not promise backwards compatibility.

The goal is to reach a point where we can declare a minimum version for
the toolchain. For instance, by waiting for some of the features to be
stabilized. Therefore, the first minimum Rust version that the kernel
will support is "in the future".

# Upgrade policy

Given we will eventually need to reach that minimum version, it would be
ideal to upgrade the compiler from time to time to be as close as
possible to that goal and find any issues sooner. In the extreme, we
could upgrade as soon as a new Rust release is out. Of course, upgrading
so often is in stark contrast to what one normally would need for GCC
and LLVM, especially given the release schedule: 6 weeks for Rust vs.
half a year for LLVM and a year for GCC.

Having said that, there is no particular advantage to updating slowly
either: kernel developers in "stable" distributions are unlikely to be
able to use their distribution-provided Rust toolchain for the kernel
anyway [3]. Instead, by routinely upgrading to the latest instead,
kernel developers using Linux distributions that track the latest Rust
release may be able to use those rather than Rust-provided ones,
especially if their package manager allows to pin / hold back /
downgrade the version for some days during windows where the version may
not match. For instance, Arch, Fedora, Gentoo and openSUSE all provide
and track the latest version of Rust as they get released every 6 weeks.

Then, when the minimum version is reached, we will stop upgrading and
decide how wide the window of support will be. For instance, a year of
Rust versions. We will probably want to start small, and then widen it
over time, just like the kernel did originally for LLVM, see commit
3519c4d ("Documentation: add minimum clang/llvm version").

# Unstable features stabilized

This upgrade allows us to remove the following unstable features since
they were stabilized:

  - `feature(explicit_generic_args_with_impl_trait)` (1.63).
  - `feature(core_ffi_c)` (1.64).
  - `feature(generic_associated_types)` (1.65).
  - `feature(const_ptr_offset_from)` (1.65, *).
  - `feature(bench_black_box)` (1.66, *).
  - `feature(pin_macro)` (1.68).

The ones marked with `*` apply only to our old `rust` branch, not
mainline yet, i.e. only for code that we may potentially upstream.

With this patch applied, the only unstable feature allowed to be used
outside the `kernel` crate is `new_uninit`, though other code to be
upstreamed may increase the list.

Please see [2] for details.

# Other required changes

Since 1.63, `rustdoc` triggers the `broken_intra_doc_links` lint for
links pointing to exported (`#[macro_export]`) `macro_rules`. An issue
was opened upstream [4], but it turns out it is intended behavior. For
the moment, just add an explicit reference for each link. Later we can
revisit this if `rustdoc` removes the compatibility measure.

Nevertheless, this was helpful to discover a link that was pointing to
the wrong place unintentionally. Since that one was actually wrong, it
is fixed in a previous commit independently.

Another change was the addition of `cfg(no_rc)` and `cfg(no_sync)` in
upstream [5], thus remove our original changes for that.

Similarly, upstream now tests that it compiles successfully with
`#[cfg(not(no_global_oom_handling))]` [6], which allow us to get rid
of some changes, such as an `#[allow(dead_code)]`.

In addition, remove another `#[allow(dead_code)]` due to new uses
within the standard library.

Finally, add `try_extend_trusted` and move the code in `spec_extend.rs`
since upstream moved it for the infallible version.

# `alloc` upgrade and reviewing

There are a large amount of changes, but the vast majority of them are
due to our `alloc` fork being upgraded at once.

There are two kinds of changes to be aware of: the ones coming from
upstream, which we should follow as closely as possible, and the updates
needed in our added fallible APIs to keep them matching the newer
infallible APIs coming from upstream.

Instead of taking a look at the diff of this patch, an alternative
approach is reviewing a diff of the changes between upstream `alloc` and
the kernel's. This allows to easily inspect the kernel additions only,
especially to check if the fallible methods we already have still match
the infallible ones in the new version coming from upstream.

Another approach is reviewing the changes introduced in the additions in
the kernel fork between the two versions. This is useful to spot
potentially unintended changes to our additions.

To apply these approaches, one may follow steps similar to the following
to generate a pair of patches that show the differences between upstream
Rust and the kernel (for the subset of `alloc` we use) before and after
applying this patch:

    # Get the difference with respect to the old version.
    git -C rust checkout $(linux/scripts/min-tool-version.sh rustc)
    git -C linux ls-tree -r --name-only HEAD -- rust/alloc |
        cut -d/ -f3- |
        grep -Fv README.md |
        xargs -IPATH cp rust/library/alloc/src/PATH linux/rust/alloc/PATH
    git -C linux diff --patch-with-stat --summary -R > old.patch
    git -C linux restore rust/alloc

    # Apply this patch.
    git -C linux am rust-upgrade.patch

    # Get the difference with respect to the new version.
    git -C rust checkout $(linux/scripts/min-tool-version.sh rustc)
    git -C linux ls-tree -r --name-only HEAD -- rust/alloc |
        cut -d/ -f3- |
        grep -Fv README.md |
        xargs -IPATH cp rust/library/alloc/src/PATH linux/rust/alloc/PATH
    git -C linux diff --patch-with-stat --summary -R > new.patch
    git -C linux restore rust/alloc

Now one may check the `new.patch` to take a look at the additions (first
approach) or at the difference between those two patches (second
approach). For the latter, a side-by-side tool is recommended.

Link: https://rust-for-linux.com/rust-version-policy [1]
Link: Rust-for-Linux#2 [2]
Link: https://lore.kernel.org/rust-for-linux/CANiq72mT3bVDKdHgaea-6WiZazd8Mvurqmqegbe5JZxVyLR8Yg@mail.gmail.com/ [3]
Link: rust-lang/rust#106142 [4]
Link: rust-lang/rust#89891 [5]
Link: rust-lang/rust#98652 [6]
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
WhatAmISupposedToPutHere pushed a commit to WhatAmISupposedToPutHere/linux that referenced this issue Apr 24, 2023
Upgrade the Rust version from 1.62.0 to 1.66.0.

The overwhelming majority of the commit is about upgrading our `alloc`
fork to the new version from upstream [1]. License has not changed [2][3]
(there were changes in the `COPYRIGHT` file, but unrelated to `alloc`).

As in the previous version upgrades (done out of tree so far), upgrading
`alloc` requires checking that our small additions (`try_*`) still match
their original (non`-try_*`) versions.

With this version upgrade, the following unstable Rust features were
stabilized: `bench_black_box` (1.66.0), `const_ptr_offset_from` (1.65.0),
`core_ffi_c` (1.64.0) and `generic_associated_types` (1.65.0). Thus
remove them.

This also implies that only two unstable features remain allowed for
non-`rust/` code: `allocator_api` and `const_refs_to_cell`.

There are some new Clippy warnings that we are triggering (i.e.
introduced since 1.62.0), as well as a few others that were not
triggered before, thus allow them in this commit and clean up or
remove them as needed later on:

  - `borrow_deref_ref` (new in 1.63.0).
  - `explicit_auto_deref` (new in 1.64.0).
  - `bool_to_int_with_if` (new in 1.65.0).
  - `needless_borrow`.
  - `type_complexity`.
  - `unnecessary_cast` (allowed only on `CONFIG_ARM`).

Furthermore, `rustdoc` lint `broken_intra_doc_links` is triggering on
links pointing to `macro_export` `macro_rules` defined in the same
module (i.e. appearing in the crate root).

However, even if the warning appears, the link still gets generated
like in previous versions, thus it is a bit confusing. An issue has
been opened upstream [4], and it appears that the link still being
generated was a compatibility measure, thus we will need to adapt
to the new behavior (done in the next patch).

In addition, there is an added `#[const_trait]` attribute in
`RawDeviceId`, due to 1.66.0's PR "Require `#[const_trait]` on `Trait`
for `impl const Trait`") [5].

Finally, the `-Aunused-imports` was added for compiling `core`. This was
fixed upstream for 1.67.0 in PR "Fix warning when libcore is compiled
with no_fp_fmt_parse" [6], and prevented for the future for that `cfg`
in PR "core: ensure `no_fp_fmt_parse builds` are warning-free" [7].

Reviewed-by: Björn Roy Baron <bjorn3_gh@protonmail.com>
Reviewed-by: Martin Rodriguez Reboredo <yakoyoku@gmail.com>
Tested-by: Martin Rodriguez Reboredo <yakoyoku@gmail.com>
Reviewed-by: Gary Guo <gary@garyguo.net>
Reviewed-by: Vincenzo Palazzo <vincenzopalazzodev@gmail.com>
Reviewed-by: Alice Ferrazzi <alice.ferrazzi@miraclelinux.com>
Tested-by: Alice Ferrazzi <alice.ferrazzi@miraclelinux.com>
Reviewed-by: Neal Gompa <neal@gompa.dev>
Tested-by: Neal Gompa <neal@gompa.dev>
Link: Rust-for-Linux#947
Link: https://github.com/rust-lang/rust/tree/1.66.0/library/alloc/src [1]
Link: https://github.com/rust-lang/rust/blob/1.66.0/library/alloc/Cargo.toml#L4 [2]
Link: https://github.com/rust-lang/rust/blob/1.66.0/COPYRIGHT [3]
Link: rust-lang/rust#106142 [4]
Link: rust-lang/rust#100982 [5]
Link: rust-lang/rust#105434 [6]
Link: rust-lang/rust#105811 [7]
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
@jyn514 jyn514 added the T-rustdoc Relevant to the rustdoc team, which will review and decide on the PR/issue. label Apr 27, 2023
herrnst pushed a commit to herrnst/linux-asahi that referenced this issue Jul 30, 2023
This is the first upgrade to the Rust toolchain since the initial Rust
merge, from 1.62.0 to 1.68.2 (i.e. the latest).

# Context

The kernel currently supports only a single Rust version [1] (rather
than a minimum) given our usage of some "unstable" Rust features [2]
which do not promise backwards compatibility.

The goal is to reach a point where we can declare a minimum version for
the toolchain. For instance, by waiting for some of the features to be
stabilized. Therefore, the first minimum Rust version that the kernel
will support is "in the future".

# Upgrade policy

Given we will eventually need to reach that minimum version, it would be
ideal to upgrade the compiler from time to time to be as close as
possible to that goal and find any issues sooner. In the extreme, we
could upgrade as soon as a new Rust release is out. Of course, upgrading
so often is in stark contrast to what one normally would need for GCC
and LLVM, especially given the release schedule: 6 weeks for Rust vs.
half a year for LLVM and a year for GCC.

Having said that, there is no particular advantage to updating slowly
either: kernel developers in "stable" distributions are unlikely to be
able to use their distribution-provided Rust toolchain for the kernel
anyway [3]. Instead, by routinely upgrading to the latest instead,
kernel developers using Linux distributions that track the latest Rust
release may be able to use those rather than Rust-provided ones,
especially if their package manager allows to pin / hold back /
downgrade the version for some days during windows where the version may
not match. For instance, Arch, Fedora, Gentoo and openSUSE all provide
and track the latest version of Rust as they get released every 6 weeks.

Then, when the minimum version is reached, we will stop upgrading and
decide how wide the window of support will be. For instance, a year of
Rust versions. We will probably want to start small, and then widen it
over time, just like the kernel did originally for LLVM, see commit
3519c4d ("Documentation: add minimum clang/llvm version").

# Unstable features stabilized

This upgrade allows us to remove the following unstable features since
they were stabilized:

  - `feature(explicit_generic_args_with_impl_trait)` (1.63).
  - `feature(core_ffi_c)` (1.64).
  - `feature(generic_associated_types)` (1.65).
  - `feature(const_ptr_offset_from)` (1.65, *).
  - `feature(bench_black_box)` (1.66, *).
  - `feature(pin_macro)` (1.68).

The ones marked with `*` apply only to our old `rust` branch, not
mainline yet, i.e. only for code that we may potentially upstream.

With this patch applied, the only unstable feature allowed to be used
outside the `kernel` crate is `new_uninit`, though other code to be
upstreamed may increase the list.

Please see [2] for details.

# Other required changes

Since 1.63, `rustdoc` triggers the `broken_intra_doc_links` lint for
links pointing to exported (`#[macro_export]`) `macro_rules`. An issue
was opened upstream [4], but it turns out it is intended behavior. For
the moment, just add an explicit reference for each link. Later we can
revisit this if `rustdoc` removes the compatibility measure.

Nevertheless, this was helpful to discover a link that was pointing to
the wrong place unintentionally. Since that one was actually wrong, it
is fixed in a previous commit independently.

Another change was the addition of `cfg(no_rc)` and `cfg(no_sync)` in
upstream [5], thus remove our original changes for that.

Similarly, upstream now tests that it compiles successfully with
`#[cfg(not(no_global_oom_handling))]` [6], which allow us to get rid
of some changes, such as an `#[allow(dead_code)]`.

In addition, remove another `#[allow(dead_code)]` due to new uses
within the standard library.

Finally, add `try_extend_trusted` and move the code in `spec_extend.rs`
since upstream moved it for the infallible version.

# `alloc` upgrade and reviewing

There are a large amount of changes, but the vast majority of them are
due to our `alloc` fork being upgraded at once.

There are two kinds of changes to be aware of: the ones coming from
upstream, which we should follow as closely as possible, and the updates
needed in our added fallible APIs to keep them matching the newer
infallible APIs coming from upstream.

Instead of taking a look at the diff of this patch, an alternative
approach is reviewing a diff of the changes between upstream `alloc` and
the kernel's. This allows to easily inspect the kernel additions only,
especially to check if the fallible methods we already have still match
the infallible ones in the new version coming from upstream.

Another approach is reviewing the changes introduced in the additions in
the kernel fork between the two versions. This is useful to spot
potentially unintended changes to our additions.

To apply these approaches, one may follow steps similar to the following
to generate a pair of patches that show the differences between upstream
Rust and the kernel (for the subset of `alloc` we use) before and after
applying this patch:

    # Get the difference with respect to the old version.
    git -C rust checkout $(linux/scripts/min-tool-version.sh rustc)
    git -C linux ls-tree -r --name-only HEAD -- rust/alloc |
        cut -d/ -f3- |
        grep -Fv README.md |
        xargs -IPATH cp rust/library/alloc/src/PATH linux/rust/alloc/PATH
    git -C linux diff --patch-with-stat --summary -R > old.patch
    git -C linux restore rust/alloc

    # Apply this patch.
    git -C linux am rust-upgrade.patch

    # Get the difference with respect to the new version.
    git -C rust checkout $(linux/scripts/min-tool-version.sh rustc)
    git -C linux ls-tree -r --name-only HEAD -- rust/alloc |
        cut -d/ -f3- |
        grep -Fv README.md |
        xargs -IPATH cp rust/library/alloc/src/PATH linux/rust/alloc/PATH
    git -C linux diff --patch-with-stat --summary -R > new.patch
    git -C linux restore rust/alloc

Now one may check the `new.patch` to take a look at the additions (first
approach) or at the difference between those two patches (second
approach). For the latter, a side-by-side tool is recommended.

Link: https://rust-for-linux.com/rust-version-policy [1]
Link: Rust-for-Linux/linux#2 [2]
Link: https://lore.kernel.org/rust-for-linux/CANiq72mT3bVDKdHgaea-6WiZazd8Mvurqmqegbe5JZxVyLR8Yg@mail.gmail.com/ [3]
Link: rust-lang/rust#106142 [4]
Link: rust-lang/rust#89891 [5]
Link: rust-lang/rust#98652 [6]
Reviewed-by: Björn Roy Baron <bjorn3_gh@protonmail.com>
Reviewed-by: Gary Guo <gary@garyguo.net>
Reviewed-By: Martin Rodriguez Reboredo <yakoyoku@gmail.com>
Tested-by: Ariel Miculas <amiculas@cisco.com>
Tested-by: David Gow <davidgow@google.com>
Tested-by: Boqun Feng <boqun.feng@gmail.com>
Link: https://lore.kernel.org/r/20230418214347.324156-4-ojeda@kernel.org
[ Removed `feature(core_ffi_c)` from `uapi` ]
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
herrnst pushed a commit to herrnst/linux-asahi that referenced this issue Aug 3, 2023
`Arc<T>::init` refers to `Arc<T>::pin_init` via an intra-doc link
using the text `pin_init`, rather than more explicitly, which makes
`rustdoc` point it to the `pin_init!` macro instead.

This is required for the compiler upgrade since the newer `rustdoc`
would trigger the `broken_intra_doc_links` lint [1], but in this case
the macro was not the intended target to begin with, and so the actual
fix is to make it point to the right place, regardless of the upgrade.

Thus make it more explicit.

Fixes: 92c4a1e ("rust: init/sync: add `InPlaceInit` trait to pin-initialize smart pointers")
Link: rust-lang/rust#106142 [1]
Reviewed-by: Gary Guo <gary@garyguo.net>
Reviewed-by: Benno Lossin <benno.lossin@proton.me>
Reviewed-by: Martin Rodriguez Reboredo <yakoyoku@gmail.com>
Reviewed-by: Björn Roy Baron <bjorn3_gh@protonmail.com>
Tested-by: Ariel Miculas <amiculas@cisco.com>
Tested-by: David Gow <davidgow@google.com>
Tested-by: Boqun Feng <boqun.feng@gmail.com>
Link: https://lore.kernel.org/r/20230418214347.324156-3-ojeda@kernel.org
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
herrnst pushed a commit to herrnst/linux-asahi that referenced this issue Aug 3, 2023
This is the first upgrade to the Rust toolchain since the initial Rust
merge, from 1.62.0 to 1.68.2 (i.e. the latest).

# Context

The kernel currently supports only a single Rust version [1] (rather
than a minimum) given our usage of some "unstable" Rust features [2]
which do not promise backwards compatibility.

The goal is to reach a point where we can declare a minimum version for
the toolchain. For instance, by waiting for some of the features to be
stabilized. Therefore, the first minimum Rust version that the kernel
will support is "in the future".

# Upgrade policy

Given we will eventually need to reach that minimum version, it would be
ideal to upgrade the compiler from time to time to be as close as
possible to that goal and find any issues sooner. In the extreme, we
could upgrade as soon as a new Rust release is out. Of course, upgrading
so often is in stark contrast to what one normally would need for GCC
and LLVM, especially given the release schedule: 6 weeks for Rust vs.
half a year for LLVM and a year for GCC.

Having said that, there is no particular advantage to updating slowly
either: kernel developers in "stable" distributions are unlikely to be
able to use their distribution-provided Rust toolchain for the kernel
anyway [3]. Instead, by routinely upgrading to the latest instead,
kernel developers using Linux distributions that track the latest Rust
release may be able to use those rather than Rust-provided ones,
especially if their package manager allows to pin / hold back /
downgrade the version for some days during windows where the version may
not match. For instance, Arch, Fedora, Gentoo and openSUSE all provide
and track the latest version of Rust as they get released every 6 weeks.

Then, when the minimum version is reached, we will stop upgrading and
decide how wide the window of support will be. For instance, a year of
Rust versions. We will probably want to start small, and then widen it
over time, just like the kernel did originally for LLVM, see commit
3519c4d ("Documentation: add minimum clang/llvm version").

# Unstable features stabilized

This upgrade allows us to remove the following unstable features since
they were stabilized:

  - `feature(explicit_generic_args_with_impl_trait)` (1.63).
  - `feature(core_ffi_c)` (1.64).
  - `feature(generic_associated_types)` (1.65).
  - `feature(const_ptr_offset_from)` (1.65, *).
  - `feature(bench_black_box)` (1.66, *).
  - `feature(pin_macro)` (1.68).

The ones marked with `*` apply only to our old `rust` branch, not
mainline yet, i.e. only for code that we may potentially upstream.

With this patch applied, the only unstable feature allowed to be used
outside the `kernel` crate is `new_uninit`, though other code to be
upstreamed may increase the list.

Please see [2] for details.

# Other required changes

Since 1.63, `rustdoc` triggers the `broken_intra_doc_links` lint for
links pointing to exported (`#[macro_export]`) `macro_rules`. An issue
was opened upstream [4], but it turns out it is intended behavior. For
the moment, just add an explicit reference for each link. Later we can
revisit this if `rustdoc` removes the compatibility measure.

Nevertheless, this was helpful to discover a link that was pointing to
the wrong place unintentionally. Since that one was actually wrong, it
is fixed in a previous commit independently.

Another change was the addition of `cfg(no_rc)` and `cfg(no_sync)` in
upstream [5], thus remove our original changes for that.

Similarly, upstream now tests that it compiles successfully with
`#[cfg(not(no_global_oom_handling))]` [6], which allow us to get rid
of some changes, such as an `#[allow(dead_code)]`.

In addition, remove another `#[allow(dead_code)]` due to new uses
within the standard library.

Finally, add `try_extend_trusted` and move the code in `spec_extend.rs`
since upstream moved it for the infallible version.

# `alloc` upgrade and reviewing

There are a large amount of changes, but the vast majority of them are
due to our `alloc` fork being upgraded at once.

There are two kinds of changes to be aware of: the ones coming from
upstream, which we should follow as closely as possible, and the updates
needed in our added fallible APIs to keep them matching the newer
infallible APIs coming from upstream.

Instead of taking a look at the diff of this patch, an alternative
approach is reviewing a diff of the changes between upstream `alloc` and
the kernel's. This allows to easily inspect the kernel additions only,
especially to check if the fallible methods we already have still match
the infallible ones in the new version coming from upstream.

Another approach is reviewing the changes introduced in the additions in
the kernel fork between the two versions. This is useful to spot
potentially unintended changes to our additions.

To apply these approaches, one may follow steps similar to the following
to generate a pair of patches that show the differences between upstream
Rust and the kernel (for the subset of `alloc` we use) before and after
applying this patch:

    # Get the difference with respect to the old version.
    git -C rust checkout $(linux/scripts/min-tool-version.sh rustc)
    git -C linux ls-tree -r --name-only HEAD -- rust/alloc |
        cut -d/ -f3- |
        grep -Fv README.md |
        xargs -IPATH cp rust/library/alloc/src/PATH linux/rust/alloc/PATH
    git -C linux diff --patch-with-stat --summary -R > old.patch
    git -C linux restore rust/alloc

    # Apply this patch.
    git -C linux am rust-upgrade.patch

    # Get the difference with respect to the new version.
    git -C rust checkout $(linux/scripts/min-tool-version.sh rustc)
    git -C linux ls-tree -r --name-only HEAD -- rust/alloc |
        cut -d/ -f3- |
        grep -Fv README.md |
        xargs -IPATH cp rust/library/alloc/src/PATH linux/rust/alloc/PATH
    git -C linux diff --patch-with-stat --summary -R > new.patch
    git -C linux restore rust/alloc

Now one may check the `new.patch` to take a look at the additions (first
approach) or at the difference between those two patches (second
approach). For the latter, a side-by-side tool is recommended.

Link: https://rust-for-linux.com/rust-version-policy [1]
Link: Rust-for-Linux/linux#2 [2]
Link: https://lore.kernel.org/rust-for-linux/CANiq72mT3bVDKdHgaea-6WiZazd8Mvurqmqegbe5JZxVyLR8Yg@mail.gmail.com/ [3]
Link: rust-lang/rust#106142 [4]
Link: rust-lang/rust#89891 [5]
Link: rust-lang/rust#98652 [6]
Reviewed-by: Björn Roy Baron <bjorn3_gh@protonmail.com>
Reviewed-by: Gary Guo <gary@garyguo.net>
Reviewed-By: Martin Rodriguez Reboredo <yakoyoku@gmail.com>
Tested-by: Ariel Miculas <amiculas@cisco.com>
Tested-by: David Gow <davidgow@google.com>
Tested-by: Boqun Feng <boqun.feng@gmail.com>
Link: https://lore.kernel.org/r/20230418214347.324156-4-ojeda@kernel.org
[ Removed `feature(core_ffi_c)` from `uapi` ]
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
herrnst pushed a commit to herrnst/linux-asahi that referenced this issue Aug 9, 2023
`Arc<T>::init` refers to `Arc<T>::pin_init` via an intra-doc link
using the text `pin_init`, rather than more explicitly, which makes
`rustdoc` point it to the `pin_init!` macro instead.

This is required for the compiler upgrade since the newer `rustdoc`
would trigger the `broken_intra_doc_links` lint [1], but in this case
the macro was not the intended target to begin with, and so the actual
fix is to make it point to the right place, regardless of the upgrade.

Thus make it more explicit.

Fixes: 92c4a1e ("rust: init/sync: add `InPlaceInit` trait to pin-initialize smart pointers")
Link: rust-lang/rust#106142 [1]
Reviewed-by: Gary Guo <gary@garyguo.net>
Reviewed-by: Benno Lossin <benno.lossin@proton.me>
Reviewed-by: Martin Rodriguez Reboredo <yakoyoku@gmail.com>
Reviewed-by: Björn Roy Baron <bjorn3_gh@protonmail.com>
Tested-by: Ariel Miculas <amiculas@cisco.com>
Tested-by: David Gow <davidgow@google.com>
Tested-by: Boqun Feng <boqun.feng@gmail.com>
Link: https://lore.kernel.org/r/20230418214347.324156-3-ojeda@kernel.org
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
herrnst pushed a commit to herrnst/linux-asahi that referenced this issue Aug 9, 2023
This is the first upgrade to the Rust toolchain since the initial Rust
merge, from 1.62.0 to 1.68.2 (i.e. the latest).

# Context

The kernel currently supports only a single Rust version [1] (rather
than a minimum) given our usage of some "unstable" Rust features [2]
which do not promise backwards compatibility.

The goal is to reach a point where we can declare a minimum version for
the toolchain. For instance, by waiting for some of the features to be
stabilized. Therefore, the first minimum Rust version that the kernel
will support is "in the future".

# Upgrade policy

Given we will eventually need to reach that minimum version, it would be
ideal to upgrade the compiler from time to time to be as close as
possible to that goal and find any issues sooner. In the extreme, we
could upgrade as soon as a new Rust release is out. Of course, upgrading
so often is in stark contrast to what one normally would need for GCC
and LLVM, especially given the release schedule: 6 weeks for Rust vs.
half a year for LLVM and a year for GCC.

Having said that, there is no particular advantage to updating slowly
either: kernel developers in "stable" distributions are unlikely to be
able to use their distribution-provided Rust toolchain for the kernel
anyway [3]. Instead, by routinely upgrading to the latest instead,
kernel developers using Linux distributions that track the latest Rust
release may be able to use those rather than Rust-provided ones,
especially if their package manager allows to pin / hold back /
downgrade the version for some days during windows where the version may
not match. For instance, Arch, Fedora, Gentoo and openSUSE all provide
and track the latest version of Rust as they get released every 6 weeks.

Then, when the minimum version is reached, we will stop upgrading and
decide how wide the window of support will be. For instance, a year of
Rust versions. We will probably want to start small, and then widen it
over time, just like the kernel did originally for LLVM, see commit
3519c4d ("Documentation: add minimum clang/llvm version").

# Unstable features stabilized

This upgrade allows us to remove the following unstable features since
they were stabilized:

  - `feature(explicit_generic_args_with_impl_trait)` (1.63).
  - `feature(core_ffi_c)` (1.64).
  - `feature(generic_associated_types)` (1.65).
  - `feature(const_ptr_offset_from)` (1.65, *).
  - `feature(bench_black_box)` (1.66, *).
  - `feature(pin_macro)` (1.68).

The ones marked with `*` apply only to our old `rust` branch, not
mainline yet, i.e. only for code that we may potentially upstream.

With this patch applied, the only unstable feature allowed to be used
outside the `kernel` crate is `new_uninit`, though other code to be
upstreamed may increase the list.

Please see [2] for details.

# Other required changes

Since 1.63, `rustdoc` triggers the `broken_intra_doc_links` lint for
links pointing to exported (`#[macro_export]`) `macro_rules`. An issue
was opened upstream [4], but it turns out it is intended behavior. For
the moment, just add an explicit reference for each link. Later we can
revisit this if `rustdoc` removes the compatibility measure.

Nevertheless, this was helpful to discover a link that was pointing to
the wrong place unintentionally. Since that one was actually wrong, it
is fixed in a previous commit independently.

Another change was the addition of `cfg(no_rc)` and `cfg(no_sync)` in
upstream [5], thus remove our original changes for that.

Similarly, upstream now tests that it compiles successfully with
`#[cfg(not(no_global_oom_handling))]` [6], which allow us to get rid
of some changes, such as an `#[allow(dead_code)]`.

In addition, remove another `#[allow(dead_code)]` due to new uses
within the standard library.

Finally, add `try_extend_trusted` and move the code in `spec_extend.rs`
since upstream moved it for the infallible version.

# `alloc` upgrade and reviewing

There are a large amount of changes, but the vast majority of them are
due to our `alloc` fork being upgraded at once.

There are two kinds of changes to be aware of: the ones coming from
upstream, which we should follow as closely as possible, and the updates
needed in our added fallible APIs to keep them matching the newer
infallible APIs coming from upstream.

Instead of taking a look at the diff of this patch, an alternative
approach is reviewing a diff of the changes between upstream `alloc` and
the kernel's. This allows to easily inspect the kernel additions only,
especially to check if the fallible methods we already have still match
the infallible ones in the new version coming from upstream.

Another approach is reviewing the changes introduced in the additions in
the kernel fork between the two versions. This is useful to spot
potentially unintended changes to our additions.

To apply these approaches, one may follow steps similar to the following
to generate a pair of patches that show the differences between upstream
Rust and the kernel (for the subset of `alloc` we use) before and after
applying this patch:

    # Get the difference with respect to the old version.
    git -C rust checkout $(linux/scripts/min-tool-version.sh rustc)
    git -C linux ls-tree -r --name-only HEAD -- rust/alloc |
        cut -d/ -f3- |
        grep -Fv README.md |
        xargs -IPATH cp rust/library/alloc/src/PATH linux/rust/alloc/PATH
    git -C linux diff --patch-with-stat --summary -R > old.patch
    git -C linux restore rust/alloc

    # Apply this patch.
    git -C linux am rust-upgrade.patch

    # Get the difference with respect to the new version.
    git -C rust checkout $(linux/scripts/min-tool-version.sh rustc)
    git -C linux ls-tree -r --name-only HEAD -- rust/alloc |
        cut -d/ -f3- |
        grep -Fv README.md |
        xargs -IPATH cp rust/library/alloc/src/PATH linux/rust/alloc/PATH
    git -C linux diff --patch-with-stat --summary -R > new.patch
    git -C linux restore rust/alloc

Now one may check the `new.patch` to take a look at the additions (first
approach) or at the difference between those two patches (second
approach). For the latter, a side-by-side tool is recommended.

Link: https://rust-for-linux.com/rust-version-policy [1]
Link: Rust-for-Linux/linux#2 [2]
Link: https://lore.kernel.org/rust-for-linux/CANiq72mT3bVDKdHgaea-6WiZazd8Mvurqmqegbe5JZxVyLR8Yg@mail.gmail.com/ [3]
Link: rust-lang/rust#106142 [4]
Link: rust-lang/rust#89891 [5]
Link: rust-lang/rust#98652 [6]
Reviewed-by: Björn Roy Baron <bjorn3_gh@protonmail.com>
Reviewed-by: Gary Guo <gary@garyguo.net>
Reviewed-By: Martin Rodriguez Reboredo <yakoyoku@gmail.com>
Tested-by: Ariel Miculas <amiculas@cisco.com>
Tested-by: David Gow <davidgow@google.com>
Tested-by: Boqun Feng <boqun.feng@gmail.com>
Link: https://lore.kernel.org/r/20230418214347.324156-4-ojeda@kernel.org
[ Removed `feature(core_ffi_c)` from `uapi` ]
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
herrnst pushed a commit to herrnst/linux-asahi that referenced this issue Aug 9, 2023
`Arc<T>::init` refers to `Arc<T>::pin_init` via an intra-doc link
using the text `pin_init`, rather than more explicitly, which makes
`rustdoc` point it to the `pin_init!` macro instead.

This is required for the compiler upgrade since the newer `rustdoc`
would trigger the `broken_intra_doc_links` lint [1], but in this case
the macro was not the intended target to begin with, and so the actual
fix is to make it point to the right place, regardless of the upgrade.

Thus make it more explicit.

Fixes: 92c4a1e ("rust: init/sync: add `InPlaceInit` trait to pin-initialize smart pointers")
Link: rust-lang/rust#106142 [1]
Reviewed-by: Gary Guo <gary@garyguo.net>
Reviewed-by: Benno Lossin <benno.lossin@proton.me>
Reviewed-by: Martin Rodriguez Reboredo <yakoyoku@gmail.com>
Reviewed-by: Björn Roy Baron <bjorn3_gh@protonmail.com>
Tested-by: Ariel Miculas <amiculas@cisco.com>
Tested-by: David Gow <davidgow@google.com>
Tested-by: Boqun Feng <boqun.feng@gmail.com>
Link: https://lore.kernel.org/r/20230418214347.324156-3-ojeda@kernel.org
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
herrnst pushed a commit to herrnst/linux-asahi that referenced this issue Aug 9, 2023
This is the first upgrade to the Rust toolchain since the initial Rust
merge, from 1.62.0 to 1.68.2 (i.e. the latest).

# Context

The kernel currently supports only a single Rust version [1] (rather
than a minimum) given our usage of some "unstable" Rust features [2]
which do not promise backwards compatibility.

The goal is to reach a point where we can declare a minimum version for
the toolchain. For instance, by waiting for some of the features to be
stabilized. Therefore, the first minimum Rust version that the kernel
will support is "in the future".

# Upgrade policy

Given we will eventually need to reach that minimum version, it would be
ideal to upgrade the compiler from time to time to be as close as
possible to that goal and find any issues sooner. In the extreme, we
could upgrade as soon as a new Rust release is out. Of course, upgrading
so often is in stark contrast to what one normally would need for GCC
and LLVM, especially given the release schedule: 6 weeks for Rust vs.
half a year for LLVM and a year for GCC.

Having said that, there is no particular advantage to updating slowly
either: kernel developers in "stable" distributions are unlikely to be
able to use their distribution-provided Rust toolchain for the kernel
anyway [3]. Instead, by routinely upgrading to the latest instead,
kernel developers using Linux distributions that track the latest Rust
release may be able to use those rather than Rust-provided ones,
especially if their package manager allows to pin / hold back /
downgrade the version for some days during windows where the version may
not match. For instance, Arch, Fedora, Gentoo and openSUSE all provide
and track the latest version of Rust as they get released every 6 weeks.

Then, when the minimum version is reached, we will stop upgrading and
decide how wide the window of support will be. For instance, a year of
Rust versions. We will probably want to start small, and then widen it
over time, just like the kernel did originally for LLVM, see commit
3519c4d ("Documentation: add minimum clang/llvm version").

# Unstable features stabilized

This upgrade allows us to remove the following unstable features since
they were stabilized:

  - `feature(explicit_generic_args_with_impl_trait)` (1.63).
  - `feature(core_ffi_c)` (1.64).
  - `feature(generic_associated_types)` (1.65).
  - `feature(const_ptr_offset_from)` (1.65, *).
  - `feature(bench_black_box)` (1.66, *).
  - `feature(pin_macro)` (1.68).

The ones marked with `*` apply only to our old `rust` branch, not
mainline yet, i.e. only for code that we may potentially upstream.

With this patch applied, the only unstable feature allowed to be used
outside the `kernel` crate is `new_uninit`, though other code to be
upstreamed may increase the list.

Please see [2] for details.

# Other required changes

Since 1.63, `rustdoc` triggers the `broken_intra_doc_links` lint for
links pointing to exported (`#[macro_export]`) `macro_rules`. An issue
was opened upstream [4], but it turns out it is intended behavior. For
the moment, just add an explicit reference for each link. Later we can
revisit this if `rustdoc` removes the compatibility measure.

Nevertheless, this was helpful to discover a link that was pointing to
the wrong place unintentionally. Since that one was actually wrong, it
is fixed in a previous commit independently.

Another change was the addition of `cfg(no_rc)` and `cfg(no_sync)` in
upstream [5], thus remove our original changes for that.

Similarly, upstream now tests that it compiles successfully with
`#[cfg(not(no_global_oom_handling))]` [6], which allow us to get rid
of some changes, such as an `#[allow(dead_code)]`.

In addition, remove another `#[allow(dead_code)]` due to new uses
within the standard library.

Finally, add `try_extend_trusted` and move the code in `spec_extend.rs`
since upstream moved it for the infallible version.

# `alloc` upgrade and reviewing

There are a large amount of changes, but the vast majority of them are
due to our `alloc` fork being upgraded at once.

There are two kinds of changes to be aware of: the ones coming from
upstream, which we should follow as closely as possible, and the updates
needed in our added fallible APIs to keep them matching the newer
infallible APIs coming from upstream.

Instead of taking a look at the diff of this patch, an alternative
approach is reviewing a diff of the changes between upstream `alloc` and
the kernel's. This allows to easily inspect the kernel additions only,
especially to check if the fallible methods we already have still match
the infallible ones in the new version coming from upstream.

Another approach is reviewing the changes introduced in the additions in
the kernel fork between the two versions. This is useful to spot
potentially unintended changes to our additions.

To apply these approaches, one may follow steps similar to the following
to generate a pair of patches that show the differences between upstream
Rust and the kernel (for the subset of `alloc` we use) before and after
applying this patch:

    # Get the difference with respect to the old version.
    git -C rust checkout $(linux/scripts/min-tool-version.sh rustc)
    git -C linux ls-tree -r --name-only HEAD -- rust/alloc |
        cut -d/ -f3- |
        grep -Fv README.md |
        xargs -IPATH cp rust/library/alloc/src/PATH linux/rust/alloc/PATH
    git -C linux diff --patch-with-stat --summary -R > old.patch
    git -C linux restore rust/alloc

    # Apply this patch.
    git -C linux am rust-upgrade.patch

    # Get the difference with respect to the new version.
    git -C rust checkout $(linux/scripts/min-tool-version.sh rustc)
    git -C linux ls-tree -r --name-only HEAD -- rust/alloc |
        cut -d/ -f3- |
        grep -Fv README.md |
        xargs -IPATH cp rust/library/alloc/src/PATH linux/rust/alloc/PATH
    git -C linux diff --patch-with-stat --summary -R > new.patch
    git -C linux restore rust/alloc

Now one may check the `new.patch` to take a look at the additions (first
approach) or at the difference between those two patches (second
approach). For the latter, a side-by-side tool is recommended.

Link: https://rust-for-linux.com/rust-version-policy [1]
Link: Rust-for-Linux/linux#2 [2]
Link: https://lore.kernel.org/rust-for-linux/CANiq72mT3bVDKdHgaea-6WiZazd8Mvurqmqegbe5JZxVyLR8Yg@mail.gmail.com/ [3]
Link: rust-lang/rust#106142 [4]
Link: rust-lang/rust#89891 [5]
Link: rust-lang/rust#98652 [6]
Reviewed-by: Björn Roy Baron <bjorn3_gh@protonmail.com>
Reviewed-by: Gary Guo <gary@garyguo.net>
Reviewed-By: Martin Rodriguez Reboredo <yakoyoku@gmail.com>
Tested-by: Ariel Miculas <amiculas@cisco.com>
Tested-by: David Gow <davidgow@google.com>
Tested-by: Boqun Feng <boqun.feng@gmail.com>
Link: https://lore.kernel.org/r/20230418214347.324156-4-ojeda@kernel.org
[ Removed `feature(core_ffi_c)` from `uapi` ]
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
herrnst pushed a commit to herrnst/linux-asahi that referenced this issue Aug 9, 2023
`Arc<T>::init` refers to `Arc<T>::pin_init` via an intra-doc link
using the text `pin_init`, rather than more explicitly, which makes
`rustdoc` point it to the `pin_init!` macro instead.

This is required for the compiler upgrade since the newer `rustdoc`
would trigger the `broken_intra_doc_links` lint [1], but in this case
the macro was not the intended target to begin with, and so the actual
fix is to make it point to the right place, regardless of the upgrade.

Thus make it more explicit.

Fixes: 92c4a1e ("rust: init/sync: add `InPlaceInit` trait to pin-initialize smart pointers")
Link: rust-lang/rust#106142 [1]
Reviewed-by: Gary Guo <gary@garyguo.net>
Reviewed-by: Benno Lossin <benno.lossin@proton.me>
Reviewed-by: Martin Rodriguez Reboredo <yakoyoku@gmail.com>
Reviewed-by: Björn Roy Baron <bjorn3_gh@protonmail.com>
Tested-by: Ariel Miculas <amiculas@cisco.com>
Tested-by: David Gow <davidgow@google.com>
Tested-by: Boqun Feng <boqun.feng@gmail.com>
Link: https://lore.kernel.org/r/20230418214347.324156-3-ojeda@kernel.org
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
herrnst pushed a commit to herrnst/linux-asahi that referenced this issue Aug 9, 2023
This is the first upgrade to the Rust toolchain since the initial Rust
merge, from 1.62.0 to 1.68.2 (i.e. the latest).

# Context

The kernel currently supports only a single Rust version [1] (rather
than a minimum) given our usage of some "unstable" Rust features [2]
which do not promise backwards compatibility.

The goal is to reach a point where we can declare a minimum version for
the toolchain. For instance, by waiting for some of the features to be
stabilized. Therefore, the first minimum Rust version that the kernel
will support is "in the future".

# Upgrade policy

Given we will eventually need to reach that minimum version, it would be
ideal to upgrade the compiler from time to time to be as close as
possible to that goal and find any issues sooner. In the extreme, we
could upgrade as soon as a new Rust release is out. Of course, upgrading
so often is in stark contrast to what one normally would need for GCC
and LLVM, especially given the release schedule: 6 weeks for Rust vs.
half a year for LLVM and a year for GCC.

Having said that, there is no particular advantage to updating slowly
either: kernel developers in "stable" distributions are unlikely to be
able to use their distribution-provided Rust toolchain for the kernel
anyway [3]. Instead, by routinely upgrading to the latest instead,
kernel developers using Linux distributions that track the latest Rust
release may be able to use those rather than Rust-provided ones,
especially if their package manager allows to pin / hold back /
downgrade the version for some days during windows where the version may
not match. For instance, Arch, Fedora, Gentoo and openSUSE all provide
and track the latest version of Rust as they get released every 6 weeks.

Then, when the minimum version is reached, we will stop upgrading and
decide how wide the window of support will be. For instance, a year of
Rust versions. We will probably want to start small, and then widen it
over time, just like the kernel did originally for LLVM, see commit
3519c4d ("Documentation: add minimum clang/llvm version").

# Unstable features stabilized

This upgrade allows us to remove the following unstable features since
they were stabilized:

  - `feature(explicit_generic_args_with_impl_trait)` (1.63).
  - `feature(core_ffi_c)` (1.64).
  - `feature(generic_associated_types)` (1.65).
  - `feature(const_ptr_offset_from)` (1.65, *).
  - `feature(bench_black_box)` (1.66, *).
  - `feature(pin_macro)` (1.68).

The ones marked with `*` apply only to our old `rust` branch, not
mainline yet, i.e. only for code that we may potentially upstream.

With this patch applied, the only unstable feature allowed to be used
outside the `kernel` crate is `new_uninit`, though other code to be
upstreamed may increase the list.

Please see [2] for details.

# Other required changes

Since 1.63, `rustdoc` triggers the `broken_intra_doc_links` lint for
links pointing to exported (`#[macro_export]`) `macro_rules`. An issue
was opened upstream [4], but it turns out it is intended behavior. For
the moment, just add an explicit reference for each link. Later we can
revisit this if `rustdoc` removes the compatibility measure.

Nevertheless, this was helpful to discover a link that was pointing to
the wrong place unintentionally. Since that one was actually wrong, it
is fixed in a previous commit independently.

Another change was the addition of `cfg(no_rc)` and `cfg(no_sync)` in
upstream [5], thus remove our original changes for that.

Similarly, upstream now tests that it compiles successfully with
`#[cfg(not(no_global_oom_handling))]` [6], which allow us to get rid
of some changes, such as an `#[allow(dead_code)]`.

In addition, remove another `#[allow(dead_code)]` due to new uses
within the standard library.

Finally, add `try_extend_trusted` and move the code in `spec_extend.rs`
since upstream moved it for the infallible version.

# `alloc` upgrade and reviewing

There are a large amount of changes, but the vast majority of them are
due to our `alloc` fork being upgraded at once.

There are two kinds of changes to be aware of: the ones coming from
upstream, which we should follow as closely as possible, and the updates
needed in our added fallible APIs to keep them matching the newer
infallible APIs coming from upstream.

Instead of taking a look at the diff of this patch, an alternative
approach is reviewing a diff of the changes between upstream `alloc` and
the kernel's. This allows to easily inspect the kernel additions only,
especially to check if the fallible methods we already have still match
the infallible ones in the new version coming from upstream.

Another approach is reviewing the changes introduced in the additions in
the kernel fork between the two versions. This is useful to spot
potentially unintended changes to our additions.

To apply these approaches, one may follow steps similar to the following
to generate a pair of patches that show the differences between upstream
Rust and the kernel (for the subset of `alloc` we use) before and after
applying this patch:

    # Get the difference with respect to the old version.
    git -C rust checkout $(linux/scripts/min-tool-version.sh rustc)
    git -C linux ls-tree -r --name-only HEAD -- rust/alloc |
        cut -d/ -f3- |
        grep -Fv README.md |
        xargs -IPATH cp rust/library/alloc/src/PATH linux/rust/alloc/PATH
    git -C linux diff --patch-with-stat --summary -R > old.patch
    git -C linux restore rust/alloc

    # Apply this patch.
    git -C linux am rust-upgrade.patch

    # Get the difference with respect to the new version.
    git -C rust checkout $(linux/scripts/min-tool-version.sh rustc)
    git -C linux ls-tree -r --name-only HEAD -- rust/alloc |
        cut -d/ -f3- |
        grep -Fv README.md |
        xargs -IPATH cp rust/library/alloc/src/PATH linux/rust/alloc/PATH
    git -C linux diff --patch-with-stat --summary -R > new.patch
    git -C linux restore rust/alloc

Now one may check the `new.patch` to take a look at the additions (first
approach) or at the difference between those two patches (second
approach). For the latter, a side-by-side tool is recommended.

Link: https://rust-for-linux.com/rust-version-policy [1]
Link: Rust-for-Linux/linux#2 [2]
Link: https://lore.kernel.org/rust-for-linux/CANiq72mT3bVDKdHgaea-6WiZazd8Mvurqmqegbe5JZxVyLR8Yg@mail.gmail.com/ [3]
Link: rust-lang/rust#106142 [4]
Link: rust-lang/rust#89891 [5]
Link: rust-lang/rust#98652 [6]
Reviewed-by: Björn Roy Baron <bjorn3_gh@protonmail.com>
Reviewed-by: Gary Guo <gary@garyguo.net>
Reviewed-By: Martin Rodriguez Reboredo <yakoyoku@gmail.com>
Tested-by: Ariel Miculas <amiculas@cisco.com>
Tested-by: David Gow <davidgow@google.com>
Tested-by: Boqun Feng <boqun.feng@gmail.com>
Link: https://lore.kernel.org/r/20230418214347.324156-4-ojeda@kernel.org
[ Removed `feature(core_ffi_c)` from `uapi` ]
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
herrnst pushed a commit to herrnst/linux-asahi that referenced this issue Aug 12, 2023
`Arc<T>::init` refers to `Arc<T>::pin_init` via an intra-doc link
using the text `pin_init`, rather than more explicitly, which makes
`rustdoc` point it to the `pin_init!` macro instead.

This is required for the compiler upgrade since the newer `rustdoc`
would trigger the `broken_intra_doc_links` lint [1], but in this case
the macro was not the intended target to begin with, and so the actual
fix is to make it point to the right place, regardless of the upgrade.

Thus make it more explicit.

Fixes: 92c4a1e ("rust: init/sync: add `InPlaceInit` trait to pin-initialize smart pointers")
Link: rust-lang/rust#106142 [1]
Reviewed-by: Gary Guo <gary@garyguo.net>
Reviewed-by: Benno Lossin <benno.lossin@proton.me>
Reviewed-by: Martin Rodriguez Reboredo <yakoyoku@gmail.com>
Reviewed-by: Björn Roy Baron <bjorn3_gh@protonmail.com>
Tested-by: Ariel Miculas <amiculas@cisco.com>
Tested-by: David Gow <davidgow@google.com>
Tested-by: Boqun Feng <boqun.feng@gmail.com>
Link: https://lore.kernel.org/r/20230418214347.324156-3-ojeda@kernel.org
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
herrnst pushed a commit to herrnst/linux-asahi that referenced this issue Aug 12, 2023
This is the first upgrade to the Rust toolchain since the initial Rust
merge, from 1.62.0 to 1.68.2 (i.e. the latest).

# Context

The kernel currently supports only a single Rust version [1] (rather
than a minimum) given our usage of some "unstable" Rust features [2]
which do not promise backwards compatibility.

The goal is to reach a point where we can declare a minimum version for
the toolchain. For instance, by waiting for some of the features to be
stabilized. Therefore, the first minimum Rust version that the kernel
will support is "in the future".

# Upgrade policy

Given we will eventually need to reach that minimum version, it would be
ideal to upgrade the compiler from time to time to be as close as
possible to that goal and find any issues sooner. In the extreme, we
could upgrade as soon as a new Rust release is out. Of course, upgrading
so often is in stark contrast to what one normally would need for GCC
and LLVM, especially given the release schedule: 6 weeks for Rust vs.
half a year for LLVM and a year for GCC.

Having said that, there is no particular advantage to updating slowly
either: kernel developers in "stable" distributions are unlikely to be
able to use their distribution-provided Rust toolchain for the kernel
anyway [3]. Instead, by routinely upgrading to the latest instead,
kernel developers using Linux distributions that track the latest Rust
release may be able to use those rather than Rust-provided ones,
especially if their package manager allows to pin / hold back /
downgrade the version for some days during windows where the version may
not match. For instance, Arch, Fedora, Gentoo and openSUSE all provide
and track the latest version of Rust as they get released every 6 weeks.

Then, when the minimum version is reached, we will stop upgrading and
decide how wide the window of support will be. For instance, a year of
Rust versions. We will probably want to start small, and then widen it
over time, just like the kernel did originally for LLVM, see commit
3519c4d ("Documentation: add minimum clang/llvm version").

# Unstable features stabilized

This upgrade allows us to remove the following unstable features since
they were stabilized:

  - `feature(explicit_generic_args_with_impl_trait)` (1.63).
  - `feature(core_ffi_c)` (1.64).
  - `feature(generic_associated_types)` (1.65).
  - `feature(const_ptr_offset_from)` (1.65, *).
  - `feature(bench_black_box)` (1.66, *).
  - `feature(pin_macro)` (1.68).

The ones marked with `*` apply only to our old `rust` branch, not
mainline yet, i.e. only for code that we may potentially upstream.

With this patch applied, the only unstable feature allowed to be used
outside the `kernel` crate is `new_uninit`, though other code to be
upstreamed may increase the list.

Please see [2] for details.

# Other required changes

Since 1.63, `rustdoc` triggers the `broken_intra_doc_links` lint for
links pointing to exported (`#[macro_export]`) `macro_rules`. An issue
was opened upstream [4], but it turns out it is intended behavior. For
the moment, just add an explicit reference for each link. Later we can
revisit this if `rustdoc` removes the compatibility measure.

Nevertheless, this was helpful to discover a link that was pointing to
the wrong place unintentionally. Since that one was actually wrong, it
is fixed in a previous commit independently.

Another change was the addition of `cfg(no_rc)` and `cfg(no_sync)` in
upstream [5], thus remove our original changes for that.

Similarly, upstream now tests that it compiles successfully with
`#[cfg(not(no_global_oom_handling))]` [6], which allow us to get rid
of some changes, such as an `#[allow(dead_code)]`.

In addition, remove another `#[allow(dead_code)]` due to new uses
within the standard library.

Finally, add `try_extend_trusted` and move the code in `spec_extend.rs`
since upstream moved it for the infallible version.

# `alloc` upgrade and reviewing

There are a large amount of changes, but the vast majority of them are
due to our `alloc` fork being upgraded at once.

There are two kinds of changes to be aware of: the ones coming from
upstream, which we should follow as closely as possible, and the updates
needed in our added fallible APIs to keep them matching the newer
infallible APIs coming from upstream.

Instead of taking a look at the diff of this patch, an alternative
approach is reviewing a diff of the changes between upstream `alloc` and
the kernel's. This allows to easily inspect the kernel additions only,
especially to check if the fallible methods we already have still match
the infallible ones in the new version coming from upstream.

Another approach is reviewing the changes introduced in the additions in
the kernel fork between the two versions. This is useful to spot
potentially unintended changes to our additions.

To apply these approaches, one may follow steps similar to the following
to generate a pair of patches that show the differences between upstream
Rust and the kernel (for the subset of `alloc` we use) before and after
applying this patch:

    # Get the difference with respect to the old version.
    git -C rust checkout $(linux/scripts/min-tool-version.sh rustc)
    git -C linux ls-tree -r --name-only HEAD -- rust/alloc |
        cut -d/ -f3- |
        grep -Fv README.md |
        xargs -IPATH cp rust/library/alloc/src/PATH linux/rust/alloc/PATH
    git -C linux diff --patch-with-stat --summary -R > old.patch
    git -C linux restore rust/alloc

    # Apply this patch.
    git -C linux am rust-upgrade.patch

    # Get the difference with respect to the new version.
    git -C rust checkout $(linux/scripts/min-tool-version.sh rustc)
    git -C linux ls-tree -r --name-only HEAD -- rust/alloc |
        cut -d/ -f3- |
        grep -Fv README.md |
        xargs -IPATH cp rust/library/alloc/src/PATH linux/rust/alloc/PATH
    git -C linux diff --patch-with-stat --summary -R > new.patch
    git -C linux restore rust/alloc

Now one may check the `new.patch` to take a look at the additions (first
approach) or at the difference between those two patches (second
approach). For the latter, a side-by-side tool is recommended.

Link: https://rust-for-linux.com/rust-version-policy [1]
Link: Rust-for-Linux/linux#2 [2]
Link: https://lore.kernel.org/rust-for-linux/CANiq72mT3bVDKdHgaea-6WiZazd8Mvurqmqegbe5JZxVyLR8Yg@mail.gmail.com/ [3]
Link: rust-lang/rust#106142 [4]
Link: rust-lang/rust#89891 [5]
Link: rust-lang/rust#98652 [6]
Reviewed-by: Björn Roy Baron <bjorn3_gh@protonmail.com>
Reviewed-by: Gary Guo <gary@garyguo.net>
Reviewed-By: Martin Rodriguez Reboredo <yakoyoku@gmail.com>
Tested-by: Ariel Miculas <amiculas@cisco.com>
Tested-by: David Gow <davidgow@google.com>
Tested-by: Boqun Feng <boqun.feng@gmail.com>
Link: https://lore.kernel.org/r/20230418214347.324156-4-ojeda@kernel.org
[ Removed `feature(core_ffi_c)` from `uapi` ]
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
herrnst pushed a commit to herrnst/linux-asahi that referenced this issue Aug 12, 2023
`Arc<T>::init` refers to `Arc<T>::pin_init` via an intra-doc link
using the text `pin_init`, rather than more explicitly, which makes
`rustdoc` point it to the `pin_init!` macro instead.

This is required for the compiler upgrade since the newer `rustdoc`
would trigger the `broken_intra_doc_links` lint [1], but in this case
the macro was not the intended target to begin with, and so the actual
fix is to make it point to the right place, regardless of the upgrade.

Thus make it more explicit.

Fixes: 92c4a1e ("rust: init/sync: add `InPlaceInit` trait to pin-initialize smart pointers")
Link: rust-lang/rust#106142 [1]
Reviewed-by: Gary Guo <gary@garyguo.net>
Reviewed-by: Benno Lossin <benno.lossin@proton.me>
Reviewed-by: Martin Rodriguez Reboredo <yakoyoku@gmail.com>
Reviewed-by: Björn Roy Baron <bjorn3_gh@protonmail.com>
Tested-by: Ariel Miculas <amiculas@cisco.com>
Tested-by: David Gow <davidgow@google.com>
Tested-by: Boqun Feng <boqun.feng@gmail.com>
Link: https://lore.kernel.org/r/20230418214347.324156-3-ojeda@kernel.org
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
herrnst pushed a commit to herrnst/linux-asahi that referenced this issue Aug 12, 2023
This is the first upgrade to the Rust toolchain since the initial Rust
merge, from 1.62.0 to 1.68.2 (i.e. the latest).

# Context

The kernel currently supports only a single Rust version [1] (rather
than a minimum) given our usage of some "unstable" Rust features [2]
which do not promise backwards compatibility.

The goal is to reach a point where we can declare a minimum version for
the toolchain. For instance, by waiting for some of the features to be
stabilized. Therefore, the first minimum Rust version that the kernel
will support is "in the future".

# Upgrade policy

Given we will eventually need to reach that minimum version, it would be
ideal to upgrade the compiler from time to time to be as close as
possible to that goal and find any issues sooner. In the extreme, we
could upgrade as soon as a new Rust release is out. Of course, upgrading
so often is in stark contrast to what one normally would need for GCC
and LLVM, especially given the release schedule: 6 weeks for Rust vs.
half a year for LLVM and a year for GCC.

Having said that, there is no particular advantage to updating slowly
either: kernel developers in "stable" distributions are unlikely to be
able to use their distribution-provided Rust toolchain for the kernel
anyway [3]. Instead, by routinely upgrading to the latest instead,
kernel developers using Linux distributions that track the latest Rust
release may be able to use those rather than Rust-provided ones,
especially if their package manager allows to pin / hold back /
downgrade the version for some days during windows where the version may
not match. For instance, Arch, Fedora, Gentoo and openSUSE all provide
and track the latest version of Rust as they get released every 6 weeks.

Then, when the minimum version is reached, we will stop upgrading and
decide how wide the window of support will be. For instance, a year of
Rust versions. We will probably want to start small, and then widen it
over time, just like the kernel did originally for LLVM, see commit
3519c4d ("Documentation: add minimum clang/llvm version").

# Unstable features stabilized

This upgrade allows us to remove the following unstable features since
they were stabilized:

  - `feature(explicit_generic_args_with_impl_trait)` (1.63).
  - `feature(core_ffi_c)` (1.64).
  - `feature(generic_associated_types)` (1.65).
  - `feature(const_ptr_offset_from)` (1.65, *).
  - `feature(bench_black_box)` (1.66, *).
  - `feature(pin_macro)` (1.68).

The ones marked with `*` apply only to our old `rust` branch, not
mainline yet, i.e. only for code that we may potentially upstream.

With this patch applied, the only unstable feature allowed to be used
outside the `kernel` crate is `new_uninit`, though other code to be
upstreamed may increase the list.

Please see [2] for details.

# Other required changes

Since 1.63, `rustdoc` triggers the `broken_intra_doc_links` lint for
links pointing to exported (`#[macro_export]`) `macro_rules`. An issue
was opened upstream [4], but it turns out it is intended behavior. For
the moment, just add an explicit reference for each link. Later we can
revisit this if `rustdoc` removes the compatibility measure.

Nevertheless, this was helpful to discover a link that was pointing to
the wrong place unintentionally. Since that one was actually wrong, it
is fixed in a previous commit independently.

Another change was the addition of `cfg(no_rc)` and `cfg(no_sync)` in
upstream [5], thus remove our original changes for that.

Similarly, upstream now tests that it compiles successfully with
`#[cfg(not(no_global_oom_handling))]` [6], which allow us to get rid
of some changes, such as an `#[allow(dead_code)]`.

In addition, remove another `#[allow(dead_code)]` due to new uses
within the standard library.

Finally, add `try_extend_trusted` and move the code in `spec_extend.rs`
since upstream moved it for the infallible version.

# `alloc` upgrade and reviewing

There are a large amount of changes, but the vast majority of them are
due to our `alloc` fork being upgraded at once.

There are two kinds of changes to be aware of: the ones coming from
upstream, which we should follow as closely as possible, and the updates
needed in our added fallible APIs to keep them matching the newer
infallible APIs coming from upstream.

Instead of taking a look at the diff of this patch, an alternative
approach is reviewing a diff of the changes between upstream `alloc` and
the kernel's. This allows to easily inspect the kernel additions only,
especially to check if the fallible methods we already have still match
the infallible ones in the new version coming from upstream.

Another approach is reviewing the changes introduced in the additions in
the kernel fork between the two versions. This is useful to spot
potentially unintended changes to our additions.

To apply these approaches, one may follow steps similar to the following
to generate a pair of patches that show the differences between upstream
Rust and the kernel (for the subset of `alloc` we use) before and after
applying this patch:

    # Get the difference with respect to the old version.
    git -C rust checkout $(linux/scripts/min-tool-version.sh rustc)
    git -C linux ls-tree -r --name-only HEAD -- rust/alloc |
        cut -d/ -f3- |
        grep -Fv README.md |
        xargs -IPATH cp rust/library/alloc/src/PATH linux/rust/alloc/PATH
    git -C linux diff --patch-with-stat --summary -R > old.patch
    git -C linux restore rust/alloc

    # Apply this patch.
    git -C linux am rust-upgrade.patch

    # Get the difference with respect to the new version.
    git -C rust checkout $(linux/scripts/min-tool-version.sh rustc)
    git -C linux ls-tree -r --name-only HEAD -- rust/alloc |
        cut -d/ -f3- |
        grep -Fv README.md |
        xargs -IPATH cp rust/library/alloc/src/PATH linux/rust/alloc/PATH
    git -C linux diff --patch-with-stat --summary -R > new.patch
    git -C linux restore rust/alloc

Now one may check the `new.patch` to take a look at the additions (first
approach) or at the difference between those two patches (second
approach). For the latter, a side-by-side tool is recommended.

Link: https://rust-for-linux.com/rust-version-policy [1]
Link: Rust-for-Linux/linux#2 [2]
Link: https://lore.kernel.org/rust-for-linux/CANiq72mT3bVDKdHgaea-6WiZazd8Mvurqmqegbe5JZxVyLR8Yg@mail.gmail.com/ [3]
Link: rust-lang/rust#106142 [4]
Link: rust-lang/rust#89891 [5]
Link: rust-lang/rust#98652 [6]
Reviewed-by: Björn Roy Baron <bjorn3_gh@protonmail.com>
Reviewed-by: Gary Guo <gary@garyguo.net>
Reviewed-By: Martin Rodriguez Reboredo <yakoyoku@gmail.com>
Tested-by: Ariel Miculas <amiculas@cisco.com>
Tested-by: David Gow <davidgow@google.com>
Tested-by: Boqun Feng <boqun.feng@gmail.com>
Link: https://lore.kernel.org/r/20230418214347.324156-4-ojeda@kernel.org
[ Removed `feature(core_ffi_c)` from `uapi` ]
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
herrnst pushed a commit to herrnst/linux-asahi that referenced this issue Aug 16, 2023
`Arc<T>::init` refers to `Arc<T>::pin_init` via an intra-doc link
using the text `pin_init`, rather than more explicitly, which makes
`rustdoc` point it to the `pin_init!` macro instead.

This is required for the compiler upgrade since the newer `rustdoc`
would trigger the `broken_intra_doc_links` lint [1], but in this case
the macro was not the intended target to begin with, and so the actual
fix is to make it point to the right place, regardless of the upgrade.

Thus make it more explicit.

Fixes: 92c4a1e ("rust: init/sync: add `InPlaceInit` trait to pin-initialize smart pointers")
Link: rust-lang/rust#106142 [1]
Reviewed-by: Gary Guo <gary@garyguo.net>
Reviewed-by: Benno Lossin <benno.lossin@proton.me>
Reviewed-by: Martin Rodriguez Reboredo <yakoyoku@gmail.com>
Reviewed-by: Björn Roy Baron <bjorn3_gh@protonmail.com>
Tested-by: Ariel Miculas <amiculas@cisco.com>
Tested-by: David Gow <davidgow@google.com>
Tested-by: Boqun Feng <boqun.feng@gmail.com>
Link: https://lore.kernel.org/r/20230418214347.324156-3-ojeda@kernel.org
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
herrnst pushed a commit to herrnst/linux-asahi that referenced this issue Aug 16, 2023
This is the first upgrade to the Rust toolchain since the initial Rust
merge, from 1.62.0 to 1.68.2 (i.e. the latest).

# Context

The kernel currently supports only a single Rust version [1] (rather
than a minimum) given our usage of some "unstable" Rust features [2]
which do not promise backwards compatibility.

The goal is to reach a point where we can declare a minimum version for
the toolchain. For instance, by waiting for some of the features to be
stabilized. Therefore, the first minimum Rust version that the kernel
will support is "in the future".

# Upgrade policy

Given we will eventually need to reach that minimum version, it would be
ideal to upgrade the compiler from time to time to be as close as
possible to that goal and find any issues sooner. In the extreme, we
could upgrade as soon as a new Rust release is out. Of course, upgrading
so often is in stark contrast to what one normally would need for GCC
and LLVM, especially given the release schedule: 6 weeks for Rust vs.
half a year for LLVM and a year for GCC.

Having said that, there is no particular advantage to updating slowly
either: kernel developers in "stable" distributions are unlikely to be
able to use their distribution-provided Rust toolchain for the kernel
anyway [3]. Instead, by routinely upgrading to the latest instead,
kernel developers using Linux distributions that track the latest Rust
release may be able to use those rather than Rust-provided ones,
especially if their package manager allows to pin / hold back /
downgrade the version for some days during windows where the version may
not match. For instance, Arch, Fedora, Gentoo and openSUSE all provide
and track the latest version of Rust as they get released every 6 weeks.

Then, when the minimum version is reached, we will stop upgrading and
decide how wide the window of support will be. For instance, a year of
Rust versions. We will probably want to start small, and then widen it
over time, just like the kernel did originally for LLVM, see commit
3519c4d ("Documentation: add minimum clang/llvm version").

# Unstable features stabilized

This upgrade allows us to remove the following unstable features since
they were stabilized:

  - `feature(explicit_generic_args_with_impl_trait)` (1.63).
  - `feature(core_ffi_c)` (1.64).
  - `feature(generic_associated_types)` (1.65).
  - `feature(const_ptr_offset_from)` (1.65, *).
  - `feature(bench_black_box)` (1.66, *).
  - `feature(pin_macro)` (1.68).

The ones marked with `*` apply only to our old `rust` branch, not
mainline yet, i.e. only for code that we may potentially upstream.

With this patch applied, the only unstable feature allowed to be used
outside the `kernel` crate is `new_uninit`, though other code to be
upstreamed may increase the list.

Please see [2] for details.

# Other required changes

Since 1.63, `rustdoc` triggers the `broken_intra_doc_links` lint for
links pointing to exported (`#[macro_export]`) `macro_rules`. An issue
was opened upstream [4], but it turns out it is intended behavior. For
the moment, just add an explicit reference for each link. Later we can
revisit this if `rustdoc` removes the compatibility measure.

Nevertheless, this was helpful to discover a link that was pointing to
the wrong place unintentionally. Since that one was actually wrong, it
is fixed in a previous commit independently.

Another change was the addition of `cfg(no_rc)` and `cfg(no_sync)` in
upstream [5], thus remove our original changes for that.

Similarly, upstream now tests that it compiles successfully with
`#[cfg(not(no_global_oom_handling))]` [6], which allow us to get rid
of some changes, such as an `#[allow(dead_code)]`.

In addition, remove another `#[allow(dead_code)]` due to new uses
within the standard library.

Finally, add `try_extend_trusted` and move the code in `spec_extend.rs`
since upstream moved it for the infallible version.

# `alloc` upgrade and reviewing

There are a large amount of changes, but the vast majority of them are
due to our `alloc` fork being upgraded at once.

There are two kinds of changes to be aware of: the ones coming from
upstream, which we should follow as closely as possible, and the updates
needed in our added fallible APIs to keep them matching the newer
infallible APIs coming from upstream.

Instead of taking a look at the diff of this patch, an alternative
approach is reviewing a diff of the changes between upstream `alloc` and
the kernel's. This allows to easily inspect the kernel additions only,
especially to check if the fallible methods we already have still match
the infallible ones in the new version coming from upstream.

Another approach is reviewing the changes introduced in the additions in
the kernel fork between the two versions. This is useful to spot
potentially unintended changes to our additions.

To apply these approaches, one may follow steps similar to the following
to generate a pair of patches that show the differences between upstream
Rust and the kernel (for the subset of `alloc` we use) before and after
applying this patch:

    # Get the difference with respect to the old version.
    git -C rust checkout $(linux/scripts/min-tool-version.sh rustc)
    git -C linux ls-tree -r --name-only HEAD -- rust/alloc |
        cut -d/ -f3- |
        grep -Fv README.md |
        xargs -IPATH cp rust/library/alloc/src/PATH linux/rust/alloc/PATH
    git -C linux diff --patch-with-stat --summary -R > old.patch
    git -C linux restore rust/alloc

    # Apply this patch.
    git -C linux am rust-upgrade.patch

    # Get the difference with respect to the new version.
    git -C rust checkout $(linux/scripts/min-tool-version.sh rustc)
    git -C linux ls-tree -r --name-only HEAD -- rust/alloc |
        cut -d/ -f3- |
        grep -Fv README.md |
        xargs -IPATH cp rust/library/alloc/src/PATH linux/rust/alloc/PATH
    git -C linux diff --patch-with-stat --summary -R > new.patch
    git -C linux restore rust/alloc

Now one may check the `new.patch` to take a look at the additions (first
approach) or at the difference between those two patches (second
approach). For the latter, a side-by-side tool is recommended.

Link: https://rust-for-linux.com/rust-version-policy [1]
Link: Rust-for-Linux/linux#2 [2]
Link: https://lore.kernel.org/rust-for-linux/CANiq72mT3bVDKdHgaea-6WiZazd8Mvurqmqegbe5JZxVyLR8Yg@mail.gmail.com/ [3]
Link: rust-lang/rust#106142 [4]
Link: rust-lang/rust#89891 [5]
Link: rust-lang/rust#98652 [6]
Reviewed-by: Björn Roy Baron <bjorn3_gh@protonmail.com>
Reviewed-by: Gary Guo <gary@garyguo.net>
Reviewed-By: Martin Rodriguez Reboredo <yakoyoku@gmail.com>
Tested-by: Ariel Miculas <amiculas@cisco.com>
Tested-by: David Gow <davidgow@google.com>
Tested-by: Boqun Feng <boqun.feng@gmail.com>
Link: https://lore.kernel.org/r/20230418214347.324156-4-ojeda@kernel.org
[ Removed `feature(core_ffi_c)` from `uapi` ]
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
herrnst pushed a commit to herrnst/linux-asahi that referenced this issue Aug 16, 2023
`Arc<T>::init` refers to `Arc<T>::pin_init` via an intra-doc link
using the text `pin_init`, rather than more explicitly, which makes
`rustdoc` point it to the `pin_init!` macro instead.

This is required for the compiler upgrade since the newer `rustdoc`
would trigger the `broken_intra_doc_links` lint [1], but in this case
the macro was not the intended target to begin with, and so the actual
fix is to make it point to the right place, regardless of the upgrade.

Thus make it more explicit.

Fixes: 92c4a1e ("rust: init/sync: add `InPlaceInit` trait to pin-initialize smart pointers")
Link: rust-lang/rust#106142 [1]
Reviewed-by: Gary Guo <gary@garyguo.net>
Reviewed-by: Benno Lossin <benno.lossin@proton.me>
Reviewed-by: Martin Rodriguez Reboredo <yakoyoku@gmail.com>
Reviewed-by: Björn Roy Baron <bjorn3_gh@protonmail.com>
Tested-by: Ariel Miculas <amiculas@cisco.com>
Tested-by: David Gow <davidgow@google.com>
Tested-by: Boqun Feng <boqun.feng@gmail.com>
Link: https://lore.kernel.org/r/20230418214347.324156-3-ojeda@kernel.org
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
herrnst pushed a commit to herrnst/linux-asahi that referenced this issue Aug 16, 2023
This is the first upgrade to the Rust toolchain since the initial Rust
merge, from 1.62.0 to 1.68.2 (i.e. the latest).

# Context

The kernel currently supports only a single Rust version [1] (rather
than a minimum) given our usage of some "unstable" Rust features [2]
which do not promise backwards compatibility.

The goal is to reach a point where we can declare a minimum version for
the toolchain. For instance, by waiting for some of the features to be
stabilized. Therefore, the first minimum Rust version that the kernel
will support is "in the future".

# Upgrade policy

Given we will eventually need to reach that minimum version, it would be
ideal to upgrade the compiler from time to time to be as close as
possible to that goal and find any issues sooner. In the extreme, we
could upgrade as soon as a new Rust release is out. Of course, upgrading
so often is in stark contrast to what one normally would need for GCC
and LLVM, especially given the release schedule: 6 weeks for Rust vs.
half a year for LLVM and a year for GCC.

Having said that, there is no particular advantage to updating slowly
either: kernel developers in "stable" distributions are unlikely to be
able to use their distribution-provided Rust toolchain for the kernel
anyway [3]. Instead, by routinely upgrading to the latest instead,
kernel developers using Linux distributions that track the latest Rust
release may be able to use those rather than Rust-provided ones,
especially if their package manager allows to pin / hold back /
downgrade the version for some days during windows where the version may
not match. For instance, Arch, Fedora, Gentoo and openSUSE all provide
and track the latest version of Rust as they get released every 6 weeks.

Then, when the minimum version is reached, we will stop upgrading and
decide how wide the window of support will be. For instance, a year of
Rust versions. We will probably want to start small, and then widen it
over time, just like the kernel did originally for LLVM, see commit
3519c4d ("Documentation: add minimum clang/llvm version").

# Unstable features stabilized

This upgrade allows us to remove the following unstable features since
they were stabilized:

  - `feature(explicit_generic_args_with_impl_trait)` (1.63).
  - `feature(core_ffi_c)` (1.64).
  - `feature(generic_associated_types)` (1.65).
  - `feature(const_ptr_offset_from)` (1.65, *).
  - `feature(bench_black_box)` (1.66, *).
  - `feature(pin_macro)` (1.68).

The ones marked with `*` apply only to our old `rust` branch, not
mainline yet, i.e. only for code that we may potentially upstream.

With this patch applied, the only unstable feature allowed to be used
outside the `kernel` crate is `new_uninit`, though other code to be
upstreamed may increase the list.

Please see [2] for details.

# Other required changes

Since 1.63, `rustdoc` triggers the `broken_intra_doc_links` lint for
links pointing to exported (`#[macro_export]`) `macro_rules`. An issue
was opened upstream [4], but it turns out it is intended behavior. For
the moment, just add an explicit reference for each link. Later we can
revisit this if `rustdoc` removes the compatibility measure.

Nevertheless, this was helpful to discover a link that was pointing to
the wrong place unintentionally. Since that one was actually wrong, it
is fixed in a previous commit independently.

Another change was the addition of `cfg(no_rc)` and `cfg(no_sync)` in
upstream [5], thus remove our original changes for that.

Similarly, upstream now tests that it compiles successfully with
`#[cfg(not(no_global_oom_handling))]` [6], which allow us to get rid
of some changes, such as an `#[allow(dead_code)]`.

In addition, remove another `#[allow(dead_code)]` due to new uses
within the standard library.

Finally, add `try_extend_trusted` and move the code in `spec_extend.rs`
since upstream moved it for the infallible version.

# `alloc` upgrade and reviewing

There are a large amount of changes, but the vast majority of them are
due to our `alloc` fork being upgraded at once.

There are two kinds of changes to be aware of: the ones coming from
upstream, which we should follow as closely as possible, and the updates
needed in our added fallible APIs to keep them matching the newer
infallible APIs coming from upstream.

Instead of taking a look at the diff of this patch, an alternative
approach is reviewing a diff of the changes between upstream `alloc` and
the kernel's. This allows to easily inspect the kernel additions only,
especially to check if the fallible methods we already have still match
the infallible ones in the new version coming from upstream.

Another approach is reviewing the changes introduced in the additions in
the kernel fork between the two versions. This is useful to spot
potentially unintended changes to our additions.

To apply these approaches, one may follow steps similar to the following
to generate a pair of patches that show the differences between upstream
Rust and the kernel (for the subset of `alloc` we use) before and after
applying this patch:

    # Get the difference with respect to the old version.
    git -C rust checkout $(linux/scripts/min-tool-version.sh rustc)
    git -C linux ls-tree -r --name-only HEAD -- rust/alloc |
        cut -d/ -f3- |
        grep -Fv README.md |
        xargs -IPATH cp rust/library/alloc/src/PATH linux/rust/alloc/PATH
    git -C linux diff --patch-with-stat --summary -R > old.patch
    git -C linux restore rust/alloc

    # Apply this patch.
    git -C linux am rust-upgrade.patch

    # Get the difference with respect to the new version.
    git -C rust checkout $(linux/scripts/min-tool-version.sh rustc)
    git -C linux ls-tree -r --name-only HEAD -- rust/alloc |
        cut -d/ -f3- |
        grep -Fv README.md |
        xargs -IPATH cp rust/library/alloc/src/PATH linux/rust/alloc/PATH
    git -C linux diff --patch-with-stat --summary -R > new.patch
    git -C linux restore rust/alloc

Now one may check the `new.patch` to take a look at the additions (first
approach) or at the difference between those two patches (second
approach). For the latter, a side-by-side tool is recommended.

Link: https://rust-for-linux.com/rust-version-policy [1]
Link: Rust-for-Linux/linux#2 [2]
Link: https://lore.kernel.org/rust-for-linux/CANiq72mT3bVDKdHgaea-6WiZazd8Mvurqmqegbe5JZxVyLR8Yg@mail.gmail.com/ [3]
Link: rust-lang/rust#106142 [4]
Link: rust-lang/rust#89891 [5]
Link: rust-lang/rust#98652 [6]
Reviewed-by: Björn Roy Baron <bjorn3_gh@protonmail.com>
Reviewed-by: Gary Guo <gary@garyguo.net>
Reviewed-By: Martin Rodriguez Reboredo <yakoyoku@gmail.com>
Tested-by: Ariel Miculas <amiculas@cisco.com>
Tested-by: David Gow <davidgow@google.com>
Tested-by: Boqun Feng <boqun.feng@gmail.com>
Link: https://lore.kernel.org/r/20230418214347.324156-4-ojeda@kernel.org
[ Removed `feature(core_ffi_c)` from `uapi` ]
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
herrnst pushed a commit to herrnst/linux-asahi that referenced this issue Aug 17, 2023
`Arc<T>::init` refers to `Arc<T>::pin_init` via an intra-doc link
using the text `pin_init`, rather than more explicitly, which makes
`rustdoc` point it to the `pin_init!` macro instead.

This is required for the compiler upgrade since the newer `rustdoc`
would trigger the `broken_intra_doc_links` lint [1], but in this case
the macro was not the intended target to begin with, and so the actual
fix is to make it point to the right place, regardless of the upgrade.

Thus make it more explicit.

Fixes: 92c4a1e ("rust: init/sync: add `InPlaceInit` trait to pin-initialize smart pointers")
Link: rust-lang/rust#106142 [1]
Reviewed-by: Gary Guo <gary@garyguo.net>
Reviewed-by: Benno Lossin <benno.lossin@proton.me>
Reviewed-by: Martin Rodriguez Reboredo <yakoyoku@gmail.com>
Reviewed-by: Björn Roy Baron <bjorn3_gh@protonmail.com>
Tested-by: Ariel Miculas <amiculas@cisco.com>
Tested-by: David Gow <davidgow@google.com>
Tested-by: Boqun Feng <boqun.feng@gmail.com>
Link: https://lore.kernel.org/r/20230418214347.324156-3-ojeda@kernel.org
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
herrnst pushed a commit to herrnst/linux-asahi that referenced this issue Aug 17, 2023
This is the first upgrade to the Rust toolchain since the initial Rust
merge, from 1.62.0 to 1.68.2 (i.e. the latest).

# Context

The kernel currently supports only a single Rust version [1] (rather
than a minimum) given our usage of some "unstable" Rust features [2]
which do not promise backwards compatibility.

The goal is to reach a point where we can declare a minimum version for
the toolchain. For instance, by waiting for some of the features to be
stabilized. Therefore, the first minimum Rust version that the kernel
will support is "in the future".

# Upgrade policy

Given we will eventually need to reach that minimum version, it would be
ideal to upgrade the compiler from time to time to be as close as
possible to that goal and find any issues sooner. In the extreme, we
could upgrade as soon as a new Rust release is out. Of course, upgrading
so often is in stark contrast to what one normally would need for GCC
and LLVM, especially given the release schedule: 6 weeks for Rust vs.
half a year for LLVM and a year for GCC.

Having said that, there is no particular advantage to updating slowly
either: kernel developers in "stable" distributions are unlikely to be
able to use their distribution-provided Rust toolchain for the kernel
anyway [3]. Instead, by routinely upgrading to the latest instead,
kernel developers using Linux distributions that track the latest Rust
release may be able to use those rather than Rust-provided ones,
especially if their package manager allows to pin / hold back /
downgrade the version for some days during windows where the version may
not match. For instance, Arch, Fedora, Gentoo and openSUSE all provide
and track the latest version of Rust as they get released every 6 weeks.

Then, when the minimum version is reached, we will stop upgrading and
decide how wide the window of support will be. For instance, a year of
Rust versions. We will probably want to start small, and then widen it
over time, just like the kernel did originally for LLVM, see commit
3519c4d ("Documentation: add minimum clang/llvm version").

# Unstable features stabilized

This upgrade allows us to remove the following unstable features since
they were stabilized:

  - `feature(explicit_generic_args_with_impl_trait)` (1.63).
  - `feature(core_ffi_c)` (1.64).
  - `feature(generic_associated_types)` (1.65).
  - `feature(const_ptr_offset_from)` (1.65, *).
  - `feature(bench_black_box)` (1.66, *).
  - `feature(pin_macro)` (1.68).

The ones marked with `*` apply only to our old `rust` branch, not
mainline yet, i.e. only for code that we may potentially upstream.

With this patch applied, the only unstable feature allowed to be used
outside the `kernel` crate is `new_uninit`, though other code to be
upstreamed may increase the list.

Please see [2] for details.

# Other required changes

Since 1.63, `rustdoc` triggers the `broken_intra_doc_links` lint for
links pointing to exported (`#[macro_export]`) `macro_rules`. An issue
was opened upstream [4], but it turns out it is intended behavior. For
the moment, just add an explicit reference for each link. Later we can
revisit this if `rustdoc` removes the compatibility measure.

Nevertheless, this was helpful to discover a link that was pointing to
the wrong place unintentionally. Since that one was actually wrong, it
is fixed in a previous commit independently.

Another change was the addition of `cfg(no_rc)` and `cfg(no_sync)` in
upstream [5], thus remove our original changes for that.

Similarly, upstream now tests that it compiles successfully with
`#[cfg(not(no_global_oom_handling))]` [6], which allow us to get rid
of some changes, such as an `#[allow(dead_code)]`.

In addition, remove another `#[allow(dead_code)]` due to new uses
within the standard library.

Finally, add `try_extend_trusted` and move the code in `spec_extend.rs`
since upstream moved it for the infallible version.

# `alloc` upgrade and reviewing

There are a large amount of changes, but the vast majority of them are
due to our `alloc` fork being upgraded at once.

There are two kinds of changes to be aware of: the ones coming from
upstream, which we should follow as closely as possible, and the updates
needed in our added fallible APIs to keep them matching the newer
infallible APIs coming from upstream.

Instead of taking a look at the diff of this patch, an alternative
approach is reviewing a diff of the changes between upstream `alloc` and
the kernel's. This allows to easily inspect the kernel additions only,
especially to check if the fallible methods we already have still match
the infallible ones in the new version coming from upstream.

Another approach is reviewing the changes introduced in the additions in
the kernel fork between the two versions. This is useful to spot
potentially unintended changes to our additions.

To apply these approaches, one may follow steps similar to the following
to generate a pair of patches that show the differences between upstream
Rust and the kernel (for the subset of `alloc` we use) before and after
applying this patch:

    # Get the difference with respect to the old version.
    git -C rust checkout $(linux/scripts/min-tool-version.sh rustc)
    git -C linux ls-tree -r --name-only HEAD -- rust/alloc |
        cut -d/ -f3- |
        grep -Fv README.md |
        xargs -IPATH cp rust/library/alloc/src/PATH linux/rust/alloc/PATH
    git -C linux diff --patch-with-stat --summary -R > old.patch
    git -C linux restore rust/alloc

    # Apply this patch.
    git -C linux am rust-upgrade.patch

    # Get the difference with respect to the new version.
    git -C rust checkout $(linux/scripts/min-tool-version.sh rustc)
    git -C linux ls-tree -r --name-only HEAD -- rust/alloc |
        cut -d/ -f3- |
        grep -Fv README.md |
        xargs -IPATH cp rust/library/alloc/src/PATH linux/rust/alloc/PATH
    git -C linux diff --patch-with-stat --summary -R > new.patch
    git -C linux restore rust/alloc

Now one may check the `new.patch` to take a look at the additions (first
approach) or at the difference between those two patches (second
approach). For the latter, a side-by-side tool is recommended.

Link: https://rust-for-linux.com/rust-version-policy [1]
Link: Rust-for-Linux/linux#2 [2]
Link: https://lore.kernel.org/rust-for-linux/CANiq72mT3bVDKdHgaea-6WiZazd8Mvurqmqegbe5JZxVyLR8Yg@mail.gmail.com/ [3]
Link: rust-lang/rust#106142 [4]
Link: rust-lang/rust#89891 [5]
Link: rust-lang/rust#98652 [6]
Reviewed-by: Björn Roy Baron <bjorn3_gh@protonmail.com>
Reviewed-by: Gary Guo <gary@garyguo.net>
Reviewed-By: Martin Rodriguez Reboredo <yakoyoku@gmail.com>
Tested-by: Ariel Miculas <amiculas@cisco.com>
Tested-by: David Gow <davidgow@google.com>
Tested-by: Boqun Feng <boqun.feng@gmail.com>
Link: https://lore.kernel.org/r/20230418214347.324156-4-ojeda@kernel.org
[ Removed `feature(core_ffi_c)` from `uapi` ]
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
herrnst pushed a commit to herrnst/linux-asahi that referenced this issue Aug 23, 2023
`Arc<T>::init` refers to `Arc<T>::pin_init` via an intra-doc link
using the text `pin_init`, rather than more explicitly, which makes
`rustdoc` point it to the `pin_init!` macro instead.

This is required for the compiler upgrade since the newer `rustdoc`
would trigger the `broken_intra_doc_links` lint [1], but in this case
the macro was not the intended target to begin with, and so the actual
fix is to make it point to the right place, regardless of the upgrade.

Thus make it more explicit.

Fixes: 92c4a1e ("rust: init/sync: add `InPlaceInit` trait to pin-initialize smart pointers")
Link: rust-lang/rust#106142 [1]
Reviewed-by: Gary Guo <gary@garyguo.net>
Reviewed-by: Benno Lossin <benno.lossin@proton.me>
Reviewed-by: Martin Rodriguez Reboredo <yakoyoku@gmail.com>
Reviewed-by: Björn Roy Baron <bjorn3_gh@protonmail.com>
Tested-by: Ariel Miculas <amiculas@cisco.com>
Tested-by: David Gow <davidgow@google.com>
Tested-by: Boqun Feng <boqun.feng@gmail.com>
Link: https://lore.kernel.org/r/20230418214347.324156-3-ojeda@kernel.org
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
herrnst pushed a commit to herrnst/linux-asahi that referenced this issue Aug 23, 2023
This is the first upgrade to the Rust toolchain since the initial Rust
merge, from 1.62.0 to 1.68.2 (i.e. the latest).

# Context

The kernel currently supports only a single Rust version [1] (rather
than a minimum) given our usage of some "unstable" Rust features [2]
which do not promise backwards compatibility.

The goal is to reach a point where we can declare a minimum version for
the toolchain. For instance, by waiting for some of the features to be
stabilized. Therefore, the first minimum Rust version that the kernel
will support is "in the future".

# Upgrade policy

Given we will eventually need to reach that minimum version, it would be
ideal to upgrade the compiler from time to time to be as close as
possible to that goal and find any issues sooner. In the extreme, we
could upgrade as soon as a new Rust release is out. Of course, upgrading
so often is in stark contrast to what one normally would need for GCC
and LLVM, especially given the release schedule: 6 weeks for Rust vs.
half a year for LLVM and a year for GCC.

Having said that, there is no particular advantage to updating slowly
either: kernel developers in "stable" distributions are unlikely to be
able to use their distribution-provided Rust toolchain for the kernel
anyway [3]. Instead, by routinely upgrading to the latest instead,
kernel developers using Linux distributions that track the latest Rust
release may be able to use those rather than Rust-provided ones,
especially if their package manager allows to pin / hold back /
downgrade the version for some days during windows where the version may
not match. For instance, Arch, Fedora, Gentoo and openSUSE all provide
and track the latest version of Rust as they get released every 6 weeks.

Then, when the minimum version is reached, we will stop upgrading and
decide how wide the window of support will be. For instance, a year of
Rust versions. We will probably want to start small, and then widen it
over time, just like the kernel did originally for LLVM, see commit
3519c4d ("Documentation: add minimum clang/llvm version").

# Unstable features stabilized

This upgrade allows us to remove the following unstable features since
they were stabilized:

  - `feature(explicit_generic_args_with_impl_trait)` (1.63).
  - `feature(core_ffi_c)` (1.64).
  - `feature(generic_associated_types)` (1.65).
  - `feature(const_ptr_offset_from)` (1.65, *).
  - `feature(bench_black_box)` (1.66, *).
  - `feature(pin_macro)` (1.68).

The ones marked with `*` apply only to our old `rust` branch, not
mainline yet, i.e. only for code that we may potentially upstream.

With this patch applied, the only unstable feature allowed to be used
outside the `kernel` crate is `new_uninit`, though other code to be
upstreamed may increase the list.

Please see [2] for details.

# Other required changes

Since 1.63, `rustdoc` triggers the `broken_intra_doc_links` lint for
links pointing to exported (`#[macro_export]`) `macro_rules`. An issue
was opened upstream [4], but it turns out it is intended behavior. For
the moment, just add an explicit reference for each link. Later we can
revisit this if `rustdoc` removes the compatibility measure.

Nevertheless, this was helpful to discover a link that was pointing to
the wrong place unintentionally. Since that one was actually wrong, it
is fixed in a previous commit independently.

Another change was the addition of `cfg(no_rc)` and `cfg(no_sync)` in
upstream [5], thus remove our original changes for that.

Similarly, upstream now tests that it compiles successfully with
`#[cfg(not(no_global_oom_handling))]` [6], which allow us to get rid
of some changes, such as an `#[allow(dead_code)]`.

In addition, remove another `#[allow(dead_code)]` due to new uses
within the standard library.

Finally, add `try_extend_trusted` and move the code in `spec_extend.rs`
since upstream moved it for the infallible version.

# `alloc` upgrade and reviewing

There are a large amount of changes, but the vast majority of them are
due to our `alloc` fork being upgraded at once.

There are two kinds of changes to be aware of: the ones coming from
upstream, which we should follow as closely as possible, and the updates
needed in our added fallible APIs to keep them matching the newer
infallible APIs coming from upstream.

Instead of taking a look at the diff of this patch, an alternative
approach is reviewing a diff of the changes between upstream `alloc` and
the kernel's. This allows to easily inspect the kernel additions only,
especially to check if the fallible methods we already have still match
the infallible ones in the new version coming from upstream.

Another approach is reviewing the changes introduced in the additions in
the kernel fork between the two versions. This is useful to spot
potentially unintended changes to our additions.

To apply these approaches, one may follow steps similar to the following
to generate a pair of patches that show the differences between upstream
Rust and the kernel (for the subset of `alloc` we use) before and after
applying this patch:

    # Get the difference with respect to the old version.
    git -C rust checkout $(linux/scripts/min-tool-version.sh rustc)
    git -C linux ls-tree -r --name-only HEAD -- rust/alloc |
        cut -d/ -f3- |
        grep -Fv README.md |
        xargs -IPATH cp rust/library/alloc/src/PATH linux/rust/alloc/PATH
    git -C linux diff --patch-with-stat --summary -R > old.patch
    git -C linux restore rust/alloc

    # Apply this patch.
    git -C linux am rust-upgrade.patch

    # Get the difference with respect to the new version.
    git -C rust checkout $(linux/scripts/min-tool-version.sh rustc)
    git -C linux ls-tree -r --name-only HEAD -- rust/alloc |
        cut -d/ -f3- |
        grep -Fv README.md |
        xargs -IPATH cp rust/library/alloc/src/PATH linux/rust/alloc/PATH
    git -C linux diff --patch-with-stat --summary -R > new.patch
    git -C linux restore rust/alloc

Now one may check the `new.patch` to take a look at the additions (first
approach) or at the difference between those two patches (second
approach). For the latter, a side-by-side tool is recommended.

Link: https://rust-for-linux.com/rust-version-policy [1]
Link: Rust-for-Linux/linux#2 [2]
Link: https://lore.kernel.org/rust-for-linux/CANiq72mT3bVDKdHgaea-6WiZazd8Mvurqmqegbe5JZxVyLR8Yg@mail.gmail.com/ [3]
Link: rust-lang/rust#106142 [4]
Link: rust-lang/rust#89891 [5]
Link: rust-lang/rust#98652 [6]
Reviewed-by: Björn Roy Baron <bjorn3_gh@protonmail.com>
Reviewed-by: Gary Guo <gary@garyguo.net>
Reviewed-By: Martin Rodriguez Reboredo <yakoyoku@gmail.com>
Tested-by: Ariel Miculas <amiculas@cisco.com>
Tested-by: David Gow <davidgow@google.com>
Tested-by: Boqun Feng <boqun.feng@gmail.com>
Link: https://lore.kernel.org/r/20230418214347.324156-4-ojeda@kernel.org
[ Removed `feature(core_ffi_c)` from `uapi` ]
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
herrnst pushed a commit to herrnst/linux-asahi that referenced this issue Aug 31, 2023
`Arc<T>::init` refers to `Arc<T>::pin_init` via an intra-doc link
using the text `pin_init`, rather than more explicitly, which makes
`rustdoc` point it to the `pin_init!` macro instead.

This is required for the compiler upgrade since the newer `rustdoc`
would trigger the `broken_intra_doc_links` lint [1], but in this case
the macro was not the intended target to begin with, and so the actual
fix is to make it point to the right place, regardless of the upgrade.

Thus make it more explicit.

Fixes: 92c4a1e ("rust: init/sync: add `InPlaceInit` trait to pin-initialize smart pointers")
Link: rust-lang/rust#106142 [1]
Reviewed-by: Gary Guo <gary@garyguo.net>
Reviewed-by: Benno Lossin <benno.lossin@proton.me>
Reviewed-by: Martin Rodriguez Reboredo <yakoyoku@gmail.com>
Reviewed-by: Björn Roy Baron <bjorn3_gh@protonmail.com>
Tested-by: Ariel Miculas <amiculas@cisco.com>
Tested-by: David Gow <davidgow@google.com>
Tested-by: Boqun Feng <boqun.feng@gmail.com>
Link: https://lore.kernel.org/r/20230418214347.324156-3-ojeda@kernel.org
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
herrnst pushed a commit to herrnst/linux-asahi that referenced this issue Aug 31, 2023
This is the first upgrade to the Rust toolchain since the initial Rust
merge, from 1.62.0 to 1.68.2 (i.e. the latest).

# Context

The kernel currently supports only a single Rust version [1] (rather
than a minimum) given our usage of some "unstable" Rust features [2]
which do not promise backwards compatibility.

The goal is to reach a point where we can declare a minimum version for
the toolchain. For instance, by waiting for some of the features to be
stabilized. Therefore, the first minimum Rust version that the kernel
will support is "in the future".

# Upgrade policy

Given we will eventually need to reach that minimum version, it would be
ideal to upgrade the compiler from time to time to be as close as
possible to that goal and find any issues sooner. In the extreme, we
could upgrade as soon as a new Rust release is out. Of course, upgrading
so often is in stark contrast to what one normally would need for GCC
and LLVM, especially given the release schedule: 6 weeks for Rust vs.
half a year for LLVM and a year for GCC.

Having said that, there is no particular advantage to updating slowly
either: kernel developers in "stable" distributions are unlikely to be
able to use their distribution-provided Rust toolchain for the kernel
anyway [3]. Instead, by routinely upgrading to the latest instead,
kernel developers using Linux distributions that track the latest Rust
release may be able to use those rather than Rust-provided ones,
especially if their package manager allows to pin / hold back /
downgrade the version for some days during windows where the version may
not match. For instance, Arch, Fedora, Gentoo and openSUSE all provide
and track the latest version of Rust as they get released every 6 weeks.

Then, when the minimum version is reached, we will stop upgrading and
decide how wide the window of support will be. For instance, a year of
Rust versions. We will probably want to start small, and then widen it
over time, just like the kernel did originally for LLVM, see commit
3519c4d ("Documentation: add minimum clang/llvm version").

# Unstable features stabilized

This upgrade allows us to remove the following unstable features since
they were stabilized:

  - `feature(explicit_generic_args_with_impl_trait)` (1.63).
  - `feature(core_ffi_c)` (1.64).
  - `feature(generic_associated_types)` (1.65).
  - `feature(const_ptr_offset_from)` (1.65, *).
  - `feature(bench_black_box)` (1.66, *).
  - `feature(pin_macro)` (1.68).

The ones marked with `*` apply only to our old `rust` branch, not
mainline yet, i.e. only for code that we may potentially upstream.

With this patch applied, the only unstable feature allowed to be used
outside the `kernel` crate is `new_uninit`, though other code to be
upstreamed may increase the list.

Please see [2] for details.

# Other required changes

Since 1.63, `rustdoc` triggers the `broken_intra_doc_links` lint for
links pointing to exported (`#[macro_export]`) `macro_rules`. An issue
was opened upstream [4], but it turns out it is intended behavior. For
the moment, just add an explicit reference for each link. Later we can
revisit this if `rustdoc` removes the compatibility measure.

Nevertheless, this was helpful to discover a link that was pointing to
the wrong place unintentionally. Since that one was actually wrong, it
is fixed in a previous commit independently.

Another change was the addition of `cfg(no_rc)` and `cfg(no_sync)` in
upstream [5], thus remove our original changes for that.

Similarly, upstream now tests that it compiles successfully with
`#[cfg(not(no_global_oom_handling))]` [6], which allow us to get rid
of some changes, such as an `#[allow(dead_code)]`.

In addition, remove another `#[allow(dead_code)]` due to new uses
within the standard library.

Finally, add `try_extend_trusted` and move the code in `spec_extend.rs`
since upstream moved it for the infallible version.

# `alloc` upgrade and reviewing

There are a large amount of changes, but the vast majority of them are
due to our `alloc` fork being upgraded at once.

There are two kinds of changes to be aware of: the ones coming from
upstream, which we should follow as closely as possible, and the updates
needed in our added fallible APIs to keep them matching the newer
infallible APIs coming from upstream.

Instead of taking a look at the diff of this patch, an alternative
approach is reviewing a diff of the changes between upstream `alloc` and
the kernel's. This allows to easily inspect the kernel additions only,
especially to check if the fallible methods we already have still match
the infallible ones in the new version coming from upstream.

Another approach is reviewing the changes introduced in the additions in
the kernel fork between the two versions. This is useful to spot
potentially unintended changes to our additions.

To apply these approaches, one may follow steps similar to the following
to generate a pair of patches that show the differences between upstream
Rust and the kernel (for the subset of `alloc` we use) before and after
applying this patch:

    # Get the difference with respect to the old version.
    git -C rust checkout $(linux/scripts/min-tool-version.sh rustc)
    git -C linux ls-tree -r --name-only HEAD -- rust/alloc |
        cut -d/ -f3- |
        grep -Fv README.md |
        xargs -IPATH cp rust/library/alloc/src/PATH linux/rust/alloc/PATH
    git -C linux diff --patch-with-stat --summary -R > old.patch
    git -C linux restore rust/alloc

    # Apply this patch.
    git -C linux am rust-upgrade.patch

    # Get the difference with respect to the new version.
    git -C rust checkout $(linux/scripts/min-tool-version.sh rustc)
    git -C linux ls-tree -r --name-only HEAD -- rust/alloc |
        cut -d/ -f3- |
        grep -Fv README.md |
        xargs -IPATH cp rust/library/alloc/src/PATH linux/rust/alloc/PATH
    git -C linux diff --patch-with-stat --summary -R > new.patch
    git -C linux restore rust/alloc

Now one may check the `new.patch` to take a look at the additions (first
approach) or at the difference between those two patches (second
approach). For the latter, a side-by-side tool is recommended.

Link: https://rust-for-linux.com/rust-version-policy [1]
Link: Rust-for-Linux/linux#2 [2]
Link: https://lore.kernel.org/rust-for-linux/CANiq72mT3bVDKdHgaea-6WiZazd8Mvurqmqegbe5JZxVyLR8Yg@mail.gmail.com/ [3]
Link: rust-lang/rust#106142 [4]
Link: rust-lang/rust#89891 [5]
Link: rust-lang/rust#98652 [6]
Reviewed-by: Björn Roy Baron <bjorn3_gh@protonmail.com>
Reviewed-by: Gary Guo <gary@garyguo.net>
Reviewed-By: Martin Rodriguez Reboredo <yakoyoku@gmail.com>
Tested-by: Ariel Miculas <amiculas@cisco.com>
Tested-by: David Gow <davidgow@google.com>
Tested-by: Boqun Feng <boqun.feng@gmail.com>
Link: https://lore.kernel.org/r/20230418214347.324156-4-ojeda@kernel.org
[ Removed `feature(core_ffi_c)` from `uapi` ]
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
herrnst pushed a commit to herrnst/linux-asahi that referenced this issue Sep 2, 2023
`Arc<T>::init` refers to `Arc<T>::pin_init` via an intra-doc link
using the text `pin_init`, rather than more explicitly, which makes
`rustdoc` point it to the `pin_init!` macro instead.

This is required for the compiler upgrade since the newer `rustdoc`
would trigger the `broken_intra_doc_links` lint [1], but in this case
the macro was not the intended target to begin with, and so the actual
fix is to make it point to the right place, regardless of the upgrade.

Thus make it more explicit.

Fixes: 92c4a1e ("rust: init/sync: add `InPlaceInit` trait to pin-initialize smart pointers")
Link: rust-lang/rust#106142 [1]
Reviewed-by: Gary Guo <gary@garyguo.net>
Reviewed-by: Benno Lossin <benno.lossin@proton.me>
Reviewed-by: Martin Rodriguez Reboredo <yakoyoku@gmail.com>
Reviewed-by: Björn Roy Baron <bjorn3_gh@protonmail.com>
Tested-by: Ariel Miculas <amiculas@cisco.com>
Tested-by: David Gow <davidgow@google.com>
Tested-by: Boqun Feng <boqun.feng@gmail.com>
Link: https://lore.kernel.org/r/20230418214347.324156-3-ojeda@kernel.org
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
herrnst pushed a commit to herrnst/linux-asahi that referenced this issue Sep 2, 2023
This is the first upgrade to the Rust toolchain since the initial Rust
merge, from 1.62.0 to 1.68.2 (i.e. the latest).

# Context

The kernel currently supports only a single Rust version [1] (rather
than a minimum) given our usage of some "unstable" Rust features [2]
which do not promise backwards compatibility.

The goal is to reach a point where we can declare a minimum version for
the toolchain. For instance, by waiting for some of the features to be
stabilized. Therefore, the first minimum Rust version that the kernel
will support is "in the future".

# Upgrade policy

Given we will eventually need to reach that minimum version, it would be
ideal to upgrade the compiler from time to time to be as close as
possible to that goal and find any issues sooner. In the extreme, we
could upgrade as soon as a new Rust release is out. Of course, upgrading
so often is in stark contrast to what one normally would need for GCC
and LLVM, especially given the release schedule: 6 weeks for Rust vs.
half a year for LLVM and a year for GCC.

Having said that, there is no particular advantage to updating slowly
either: kernel developers in "stable" distributions are unlikely to be
able to use their distribution-provided Rust toolchain for the kernel
anyway [3]. Instead, by routinely upgrading to the latest instead,
kernel developers using Linux distributions that track the latest Rust
release may be able to use those rather than Rust-provided ones,
especially if their package manager allows to pin / hold back /
downgrade the version for some days during windows where the version may
not match. For instance, Arch, Fedora, Gentoo and openSUSE all provide
and track the latest version of Rust as they get released every 6 weeks.

Then, when the minimum version is reached, we will stop upgrading and
decide how wide the window of support will be. For instance, a year of
Rust versions. We will probably want to start small, and then widen it
over time, just like the kernel did originally for LLVM, see commit
3519c4d ("Documentation: add minimum clang/llvm version").

# Unstable features stabilized

This upgrade allows us to remove the following unstable features since
they were stabilized:

  - `feature(explicit_generic_args_with_impl_trait)` (1.63).
  - `feature(core_ffi_c)` (1.64).
  - `feature(generic_associated_types)` (1.65).
  - `feature(const_ptr_offset_from)` (1.65, *).
  - `feature(bench_black_box)` (1.66, *).
  - `feature(pin_macro)` (1.68).

The ones marked with `*` apply only to our old `rust` branch, not
mainline yet, i.e. only for code that we may potentially upstream.

With this patch applied, the only unstable feature allowed to be used
outside the `kernel` crate is `new_uninit`, though other code to be
upstreamed may increase the list.

Please see [2] for details.

# Other required changes

Since 1.63, `rustdoc` triggers the `broken_intra_doc_links` lint for
links pointing to exported (`#[macro_export]`) `macro_rules`. An issue
was opened upstream [4], but it turns out it is intended behavior. For
the moment, just add an explicit reference for each link. Later we can
revisit this if `rustdoc` removes the compatibility measure.

Nevertheless, this was helpful to discover a link that was pointing to
the wrong place unintentionally. Since that one was actually wrong, it
is fixed in a previous commit independently.

Another change was the addition of `cfg(no_rc)` and `cfg(no_sync)` in
upstream [5], thus remove our original changes for that.

Similarly, upstream now tests that it compiles successfully with
`#[cfg(not(no_global_oom_handling))]` [6], which allow us to get rid
of some changes, such as an `#[allow(dead_code)]`.

In addition, remove another `#[allow(dead_code)]` due to new uses
within the standard library.

Finally, add `try_extend_trusted` and move the code in `spec_extend.rs`
since upstream moved it for the infallible version.

# `alloc` upgrade and reviewing

There are a large amount of changes, but the vast majority of them are
due to our `alloc` fork being upgraded at once.

There are two kinds of changes to be aware of: the ones coming from
upstream, which we should follow as closely as possible, and the updates
needed in our added fallible APIs to keep them matching the newer
infallible APIs coming from upstream.

Instead of taking a look at the diff of this patch, an alternative
approach is reviewing a diff of the changes between upstream `alloc` and
the kernel's. This allows to easily inspect the kernel additions only,
especially to check if the fallible methods we already have still match
the infallible ones in the new version coming from upstream.

Another approach is reviewing the changes introduced in the additions in
the kernel fork between the two versions. This is useful to spot
potentially unintended changes to our additions.

To apply these approaches, one may follow steps similar to the following
to generate a pair of patches that show the differences between upstream
Rust and the kernel (for the subset of `alloc` we use) before and after
applying this patch:

    # Get the difference with respect to the old version.
    git -C rust checkout $(linux/scripts/min-tool-version.sh rustc)
    git -C linux ls-tree -r --name-only HEAD -- rust/alloc |
        cut -d/ -f3- |
        grep -Fv README.md |
        xargs -IPATH cp rust/library/alloc/src/PATH linux/rust/alloc/PATH
    git -C linux diff --patch-with-stat --summary -R > old.patch
    git -C linux restore rust/alloc

    # Apply this patch.
    git -C linux am rust-upgrade.patch

    # Get the difference with respect to the new version.
    git -C rust checkout $(linux/scripts/min-tool-version.sh rustc)
    git -C linux ls-tree -r --name-only HEAD -- rust/alloc |
        cut -d/ -f3- |
        grep -Fv README.md |
        xargs -IPATH cp rust/library/alloc/src/PATH linux/rust/alloc/PATH
    git -C linux diff --patch-with-stat --summary -R > new.patch
    git -C linux restore rust/alloc

Now one may check the `new.patch` to take a look at the additions (first
approach) or at the difference between those two patches (second
approach). For the latter, a side-by-side tool is recommended.

Link: https://rust-for-linux.com/rust-version-policy [1]
Link: Rust-for-Linux/linux#2 [2]
Link: https://lore.kernel.org/rust-for-linux/CANiq72mT3bVDKdHgaea-6WiZazd8Mvurqmqegbe5JZxVyLR8Yg@mail.gmail.com/ [3]
Link: rust-lang/rust#106142 [4]
Link: rust-lang/rust#89891 [5]
Link: rust-lang/rust#98652 [6]
Reviewed-by: Björn Roy Baron <bjorn3_gh@protonmail.com>
Reviewed-by: Gary Guo <gary@garyguo.net>
Reviewed-By: Martin Rodriguez Reboredo <yakoyoku@gmail.com>
Tested-by: Ariel Miculas <amiculas@cisco.com>
Tested-by: David Gow <davidgow@google.com>
Tested-by: Boqun Feng <boqun.feng@gmail.com>
Link: https://lore.kernel.org/r/20230418214347.324156-4-ojeda@kernel.org
[ Removed `feature(core_ffi_c)` from `uapi` ]
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
herrnst pushed a commit to herrnst/linux-asahi that referenced this issue Sep 7, 2023
`Arc<T>::init` refers to `Arc<T>::pin_init` via an intra-doc link
using the text `pin_init`, rather than more explicitly, which makes
`rustdoc` point it to the `pin_init!` macro instead.

This is required for the compiler upgrade since the newer `rustdoc`
would trigger the `broken_intra_doc_links` lint [1], but in this case
the macro was not the intended target to begin with, and so the actual
fix is to make it point to the right place, regardless of the upgrade.

Thus make it more explicit.

Fixes: 92c4a1e ("rust: init/sync: add `InPlaceInit` trait to pin-initialize smart pointers")
Link: rust-lang/rust#106142 [1]
Reviewed-by: Gary Guo <gary@garyguo.net>
Reviewed-by: Benno Lossin <benno.lossin@proton.me>
Reviewed-by: Martin Rodriguez Reboredo <yakoyoku@gmail.com>
Reviewed-by: Björn Roy Baron <bjorn3_gh@protonmail.com>
Tested-by: Ariel Miculas <amiculas@cisco.com>
Tested-by: David Gow <davidgow@google.com>
Tested-by: Boqun Feng <boqun.feng@gmail.com>
Link: https://lore.kernel.org/r/20230418214347.324156-3-ojeda@kernel.org
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
herrnst pushed a commit to herrnst/linux-asahi that referenced this issue Sep 7, 2023
This is the first upgrade to the Rust toolchain since the initial Rust
merge, from 1.62.0 to 1.68.2 (i.e. the latest).

# Context

The kernel currently supports only a single Rust version [1] (rather
than a minimum) given our usage of some "unstable" Rust features [2]
which do not promise backwards compatibility.

The goal is to reach a point where we can declare a minimum version for
the toolchain. For instance, by waiting for some of the features to be
stabilized. Therefore, the first minimum Rust version that the kernel
will support is "in the future".

# Upgrade policy

Given we will eventually need to reach that minimum version, it would be
ideal to upgrade the compiler from time to time to be as close as
possible to that goal and find any issues sooner. In the extreme, we
could upgrade as soon as a new Rust release is out. Of course, upgrading
so often is in stark contrast to what one normally would need for GCC
and LLVM, especially given the release schedule: 6 weeks for Rust vs.
half a year for LLVM and a year for GCC.

Having said that, there is no particular advantage to updating slowly
either: kernel developers in "stable" distributions are unlikely to be
able to use their distribution-provided Rust toolchain for the kernel
anyway [3]. Instead, by routinely upgrading to the latest instead,
kernel developers using Linux distributions that track the latest Rust
release may be able to use those rather than Rust-provided ones,
especially if their package manager allows to pin / hold back /
downgrade the version for some days during windows where the version may
not match. For instance, Arch, Fedora, Gentoo and openSUSE all provide
and track the latest version of Rust as they get released every 6 weeks.

Then, when the minimum version is reached, we will stop upgrading and
decide how wide the window of support will be. For instance, a year of
Rust versions. We will probably want to start small, and then widen it
over time, just like the kernel did originally for LLVM, see commit
3519c4d ("Documentation: add minimum clang/llvm version").

# Unstable features stabilized

This upgrade allows us to remove the following unstable features since
they were stabilized:

  - `feature(explicit_generic_args_with_impl_trait)` (1.63).
  - `feature(core_ffi_c)` (1.64).
  - `feature(generic_associated_types)` (1.65).
  - `feature(const_ptr_offset_from)` (1.65, *).
  - `feature(bench_black_box)` (1.66, *).
  - `feature(pin_macro)` (1.68).

The ones marked with `*` apply only to our old `rust` branch, not
mainline yet, i.e. only for code that we may potentially upstream.

With this patch applied, the only unstable feature allowed to be used
outside the `kernel` crate is `new_uninit`, though other code to be
upstreamed may increase the list.

Please see [2] for details.

# Other required changes

Since 1.63, `rustdoc` triggers the `broken_intra_doc_links` lint for
links pointing to exported (`#[macro_export]`) `macro_rules`. An issue
was opened upstream [4], but it turns out it is intended behavior. For
the moment, just add an explicit reference for each link. Later we can
revisit this if `rustdoc` removes the compatibility measure.

Nevertheless, this was helpful to discover a link that was pointing to
the wrong place unintentionally. Since that one was actually wrong, it
is fixed in a previous commit independently.

Another change was the addition of `cfg(no_rc)` and `cfg(no_sync)` in
upstream [5], thus remove our original changes for that.

Similarly, upstream now tests that it compiles successfully with
`#[cfg(not(no_global_oom_handling))]` [6], which allow us to get rid
of some changes, such as an `#[allow(dead_code)]`.

In addition, remove another `#[allow(dead_code)]` due to new uses
within the standard library.

Finally, add `try_extend_trusted` and move the code in `spec_extend.rs`
since upstream moved it for the infallible version.

# `alloc` upgrade and reviewing

There are a large amount of changes, but the vast majority of them are
due to our `alloc` fork being upgraded at once.

There are two kinds of changes to be aware of: the ones coming from
upstream, which we should follow as closely as possible, and the updates
needed in our added fallible APIs to keep them matching the newer
infallible APIs coming from upstream.

Instead of taking a look at the diff of this patch, an alternative
approach is reviewing a diff of the changes between upstream `alloc` and
the kernel's. This allows to easily inspect the kernel additions only,
especially to check if the fallible methods we already have still match
the infallible ones in the new version coming from upstream.

Another approach is reviewing the changes introduced in the additions in
the kernel fork between the two versions. This is useful to spot
potentially unintended changes to our additions.

To apply these approaches, one may follow steps similar to the following
to generate a pair of patches that show the differences between upstream
Rust and the kernel (for the subset of `alloc` we use) before and after
applying this patch:

    # Get the difference with respect to the old version.
    git -C rust checkout $(linux/scripts/min-tool-version.sh rustc)
    git -C linux ls-tree -r --name-only HEAD -- rust/alloc |
        cut -d/ -f3- |
        grep -Fv README.md |
        xargs -IPATH cp rust/library/alloc/src/PATH linux/rust/alloc/PATH
    git -C linux diff --patch-with-stat --summary -R > old.patch
    git -C linux restore rust/alloc

    # Apply this patch.
    git -C linux am rust-upgrade.patch

    # Get the difference with respect to the new version.
    git -C rust checkout $(linux/scripts/min-tool-version.sh rustc)
    git -C linux ls-tree -r --name-only HEAD -- rust/alloc |
        cut -d/ -f3- |
        grep -Fv README.md |
        xargs -IPATH cp rust/library/alloc/src/PATH linux/rust/alloc/PATH
    git -C linux diff --patch-with-stat --summary -R > new.patch
    git -C linux restore rust/alloc

Now one may check the `new.patch` to take a look at the additions (first
approach) or at the difference between those two patches (second
approach). For the latter, a side-by-side tool is recommended.

Link: https://rust-for-linux.com/rust-version-policy [1]
Link: Rust-for-Linux/linux#2 [2]
Link: https://lore.kernel.org/rust-for-linux/CANiq72mT3bVDKdHgaea-6WiZazd8Mvurqmqegbe5JZxVyLR8Yg@mail.gmail.com/ [3]
Link: rust-lang/rust#106142 [4]
Link: rust-lang/rust#89891 [5]
Link: rust-lang/rust#98652 [6]
Reviewed-by: Björn Roy Baron <bjorn3_gh@protonmail.com>
Reviewed-by: Gary Guo <gary@garyguo.net>
Reviewed-By: Martin Rodriguez Reboredo <yakoyoku@gmail.com>
Tested-by: Ariel Miculas <amiculas@cisco.com>
Tested-by: David Gow <davidgow@google.com>
Tested-by: Boqun Feng <boqun.feng@gmail.com>
Link: https://lore.kernel.org/r/20230418214347.324156-4-ojeda@kernel.org
[ Removed `feature(core_ffi_c)` from `uapi` ]
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
herrnst pushed a commit to herrnst/linux-asahi that referenced this issue Sep 14, 2023
`Arc<T>::init` refers to `Arc<T>::pin_init` via an intra-doc link
using the text `pin_init`, rather than more explicitly, which makes
`rustdoc` point it to the `pin_init!` macro instead.

This is required for the compiler upgrade since the newer `rustdoc`
would trigger the `broken_intra_doc_links` lint [1], but in this case
the macro was not the intended target to begin with, and so the actual
fix is to make it point to the right place, regardless of the upgrade.

Thus make it more explicit.

Fixes: 92c4a1e ("rust: init/sync: add `InPlaceInit` trait to pin-initialize smart pointers")
Link: rust-lang/rust#106142 [1]
Reviewed-by: Gary Guo <gary@garyguo.net>
Reviewed-by: Benno Lossin <benno.lossin@proton.me>
Reviewed-by: Martin Rodriguez Reboredo <yakoyoku@gmail.com>
Reviewed-by: Björn Roy Baron <bjorn3_gh@protonmail.com>
Tested-by: Ariel Miculas <amiculas@cisco.com>
Tested-by: David Gow <davidgow@google.com>
Tested-by: Boqun Feng <boqun.feng@gmail.com>
Link: https://lore.kernel.org/r/20230418214347.324156-3-ojeda@kernel.org
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
herrnst pushed a commit to herrnst/linux-asahi that referenced this issue Sep 14, 2023
This is the first upgrade to the Rust toolchain since the initial Rust
merge, from 1.62.0 to 1.68.2 (i.e. the latest).

# Context

The kernel currently supports only a single Rust version [1] (rather
than a minimum) given our usage of some "unstable" Rust features [2]
which do not promise backwards compatibility.

The goal is to reach a point where we can declare a minimum version for
the toolchain. For instance, by waiting for some of the features to be
stabilized. Therefore, the first minimum Rust version that the kernel
will support is "in the future".

# Upgrade policy

Given we will eventually need to reach that minimum version, it would be
ideal to upgrade the compiler from time to time to be as close as
possible to that goal and find any issues sooner. In the extreme, we
could upgrade as soon as a new Rust release is out. Of course, upgrading
so often is in stark contrast to what one normally would need for GCC
and LLVM, especially given the release schedule: 6 weeks for Rust vs.
half a year for LLVM and a year for GCC.

Having said that, there is no particular advantage to updating slowly
either: kernel developers in "stable" distributions are unlikely to be
able to use their distribution-provided Rust toolchain for the kernel
anyway [3]. Instead, by routinely upgrading to the latest instead,
kernel developers using Linux distributions that track the latest Rust
release may be able to use those rather than Rust-provided ones,
especially if their package manager allows to pin / hold back /
downgrade the version for some days during windows where the version may
not match. For instance, Arch, Fedora, Gentoo and openSUSE all provide
and track the latest version of Rust as they get released every 6 weeks.

Then, when the minimum version is reached, we will stop upgrading and
decide how wide the window of support will be. For instance, a year of
Rust versions. We will probably want to start small, and then widen it
over time, just like the kernel did originally for LLVM, see commit
3519c4d ("Documentation: add minimum clang/llvm version").

# Unstable features stabilized

This upgrade allows us to remove the following unstable features since
they were stabilized:

  - `feature(explicit_generic_args_with_impl_trait)` (1.63).
  - `feature(core_ffi_c)` (1.64).
  - `feature(generic_associated_types)` (1.65).
  - `feature(const_ptr_offset_from)` (1.65, *).
  - `feature(bench_black_box)` (1.66, *).
  - `feature(pin_macro)` (1.68).

The ones marked with `*` apply only to our old `rust` branch, not
mainline yet, i.e. only for code that we may potentially upstream.

With this patch applied, the only unstable feature allowed to be used
outside the `kernel` crate is `new_uninit`, though other code to be
upstreamed may increase the list.

Please see [2] for details.

# Other required changes

Since 1.63, `rustdoc` triggers the `broken_intra_doc_links` lint for
links pointing to exported (`#[macro_export]`) `macro_rules`. An issue
was opened upstream [4], but it turns out it is intended behavior. For
the moment, just add an explicit reference for each link. Later we can
revisit this if `rustdoc` removes the compatibility measure.

Nevertheless, this was helpful to discover a link that was pointing to
the wrong place unintentionally. Since that one was actually wrong, it
is fixed in a previous commit independently.

Another change was the addition of `cfg(no_rc)` and `cfg(no_sync)` in
upstream [5], thus remove our original changes for that.

Similarly, upstream now tests that it compiles successfully with
`#[cfg(not(no_global_oom_handling))]` [6], which allow us to get rid
of some changes, such as an `#[allow(dead_code)]`.

In addition, remove another `#[allow(dead_code)]` due to new uses
within the standard library.

Finally, add `try_extend_trusted` and move the code in `spec_extend.rs`
since upstream moved it for the infallible version.

# `alloc` upgrade and reviewing

There are a large amount of changes, but the vast majority of them are
due to our `alloc` fork being upgraded at once.

There are two kinds of changes to be aware of: the ones coming from
upstream, which we should follow as closely as possible, and the updates
needed in our added fallible APIs to keep them matching the newer
infallible APIs coming from upstream.

Instead of taking a look at the diff of this patch, an alternative
approach is reviewing a diff of the changes between upstream `alloc` and
the kernel's. This allows to easily inspect the kernel additions only,
especially to check if the fallible methods we already have still match
the infallible ones in the new version coming from upstream.

Another approach is reviewing the changes introduced in the additions in
the kernel fork between the two versions. This is useful to spot
potentially unintended changes to our additions.

To apply these approaches, one may follow steps similar to the following
to generate a pair of patches that show the differences between upstream
Rust and the kernel (for the subset of `alloc` we use) before and after
applying this patch:

    # Get the difference with respect to the old version.
    git -C rust checkout $(linux/scripts/min-tool-version.sh rustc)
    git -C linux ls-tree -r --name-only HEAD -- rust/alloc |
        cut -d/ -f3- |
        grep -Fv README.md |
        xargs -IPATH cp rust/library/alloc/src/PATH linux/rust/alloc/PATH
    git -C linux diff --patch-with-stat --summary -R > old.patch
    git -C linux restore rust/alloc

    # Apply this patch.
    git -C linux am rust-upgrade.patch

    # Get the difference with respect to the new version.
    git -C rust checkout $(linux/scripts/min-tool-version.sh rustc)
    git -C linux ls-tree -r --name-only HEAD -- rust/alloc |
        cut -d/ -f3- |
        grep -Fv README.md |
        xargs -IPATH cp rust/library/alloc/src/PATH linux/rust/alloc/PATH
    git -C linux diff --patch-with-stat --summary -R > new.patch
    git -C linux restore rust/alloc

Now one may check the `new.patch` to take a look at the additions (first
approach) or at the difference between those two patches (second
approach). For the latter, a side-by-side tool is recommended.

Link: https://rust-for-linux.com/rust-version-policy [1]
Link: Rust-for-Linux/linux#2 [2]
Link: https://lore.kernel.org/rust-for-linux/CANiq72mT3bVDKdHgaea-6WiZazd8Mvurqmqegbe5JZxVyLR8Yg@mail.gmail.com/ [3]
Link: rust-lang/rust#106142 [4]
Link: rust-lang/rust#89891 [5]
Link: rust-lang/rust#98652 [6]
Reviewed-by: Björn Roy Baron <bjorn3_gh@protonmail.com>
Reviewed-by: Gary Guo <gary@garyguo.net>
Reviewed-By: Martin Rodriguez Reboredo <yakoyoku@gmail.com>
Tested-by: Ariel Miculas <amiculas@cisco.com>
Tested-by: David Gow <davidgow@google.com>
Tested-by: Boqun Feng <boqun.feng@gmail.com>
Link: https://lore.kernel.org/r/20230418214347.324156-4-ojeda@kernel.org
[ Removed `feature(core_ffi_c)` from `uapi` ]
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
kkpan11 pushed a commit to kkpan11/AsahiLinux-linux that referenced this issue Feb 3, 2024
Upgrade the Rust version from 1.62.0 to 1.66.0.

The overwhelming majority of the commit is about upgrading our `alloc`
fork to the new version from upstream [1]. License has not changed [2][3]
(there were changes in the `COPYRIGHT` file, but unrelated to `alloc`).

As in the previous version upgrades (done out of tree so far), upgrading
`alloc` requires checking that our small additions (`try_*`) still match
their original (non`-try_*`) versions.

With this version upgrade, the following unstable Rust features were
stabilized: `bench_black_box` (1.66.0), `const_ptr_offset_from` (1.65.0),
`core_ffi_c` (1.64.0) and `generic_associated_types` (1.65.0). Thus
remove them.

This also implies that only two unstable features remain allowed for
non-`rust/` code: `allocator_api` and `const_refs_to_cell`.

There are some new Clippy warnings that we are triggering (i.e.
introduced since 1.62.0), as well as a few others that were not
triggered before, thus allow them in this commit and clean up or
remove them as needed later on:

  - `borrow_deref_ref` (new in 1.63.0).
  - `explicit_auto_deref` (new in 1.64.0).
  - `bool_to_int_with_if` (new in 1.65.0).
  - `needless_borrow`.
  - `type_complexity`.
  - `unnecessary_cast` (allowed only on `CONFIG_ARM`).

Furthermore, `rustdoc` lint `broken_intra_doc_links` is triggering on
links pointing to `macro_export` `macro_rules` defined in the same
module (i.e. appearing in the crate root).

However, even if the warning appears, the link still gets generated
like in previous versions, thus it is a bit confusing. An issue has
been opened upstream [4], and it appears that the link still being
generated was a compatibility measure, thus we will need to adapt
to the new behavior (done in the next patch).

In addition, there is an added `#[const_trait]` attribute in
`RawDeviceId`, due to 1.66.0's PR "Require `#[const_trait]` on `Trait`
for `impl const Trait`") [5].

Finally, the `-Aunused-imports` was added for compiling `core`. This was
fixed upstream for 1.67.0 in PR "Fix warning when libcore is compiled
with no_fp_fmt_parse" [6], and prevented for the future for that `cfg`
in PR "core: ensure `no_fp_fmt_parse builds` are warning-free" [7].

Reviewed-by: Björn Roy Baron <bjorn3_gh@protonmail.com>
Reviewed-by: Martin Rodriguez Reboredo <yakoyoku@gmail.com>
Tested-by: Martin Rodriguez Reboredo <yakoyoku@gmail.com>
Reviewed-by: Gary Guo <gary@garyguo.net>
Reviewed-by: Vincenzo Palazzo <vincenzopalazzodev@gmail.com>
Reviewed-by: Alice Ferrazzi <alice.ferrazzi@miraclelinux.com>
Tested-by: Alice Ferrazzi <alice.ferrazzi@miraclelinux.com>
Reviewed-by: Neal Gompa <neal@gompa.dev>
Tested-by: Neal Gompa <neal@gompa.dev>
Link: Rust-for-Linux/linux#947
Link: https://github.com/rust-lang/rust/tree/1.66.0/library/alloc/src [1]
Link: https://github.com/rust-lang/rust/blob/1.66.0/library/alloc/Cargo.toml#L4 [2]
Link: https://github.com/rust-lang/rust/blob/1.66.0/COPYRIGHT [3]
Link: rust-lang/rust#106142 [4]
Link: rust-lang/rust#100982 [5]
Link: rust-lang/rust#105434 [6]
Link: rust-lang/rust#105811 [7]
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
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A-intra-doc-links Area: Intra-doc links, the ability to link to items in docs by name A-macros Area: All kinds of macros (custom derive, macro_rules!, proc macros, ..) C-bug Category: This is a bug. T-rustdoc Relevant to the rustdoc team, which will review and decide on the PR/issue.
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