From 134fede4eecfcbe7900e789f625fa6f9c3a8cd0e Mon Sep 17 00:00:00 2001 From: Martin KaFai Lau Date: Thu, 27 Aug 2020 18:18:13 -0700 Subject: [PATCH] bpf: Relax max_entries check for most of the inner map types Most of the maps do not use max_entries during verification time. Thus, those map_meta_equal() do not need to enforce max_entries when it is inserted as an inner map during runtime. The max_entries check is removed from the default implementation bpf_map_meta_equal(). The prog_array_map and xsk_map are exception. Its map_gen_lookup uses max_entries to generate inline lookup code. Thus, they will implement its own map_meta_equal() to enforce max_entries. Since there are only two cases now, the max_entries check is not refactored and stays in its own .c file. Signed-off-by: Martin KaFai Lau Signed-off-by: Daniel Borkmann Link: https://lore.kernel.org/bpf/20200828011813.1970516-1-kafai@fb.com --- kernel/bpf/arraymap.c | 9 ++++++++- kernel/bpf/map_in_map.c | 3 +-- net/xdp/xskmap.c | 9 ++++++++- 3 files changed, 17 insertions(+), 4 deletions(-) diff --git a/kernel/bpf/arraymap.c b/kernel/bpf/arraymap.c index 40d1f7f94307..d851ebbcf302 100644 --- a/kernel/bpf/arraymap.c +++ b/kernel/bpf/arraymap.c @@ -487,6 +487,13 @@ static int array_map_mmap(struct bpf_map *map, struct vm_area_struct *vma) vma->vm_pgoff + pgoff); } +static bool array_map_meta_equal(const struct bpf_map *meta0, + const struct bpf_map *meta1) +{ + return meta0->max_entries == meta1->max_entries && + bpf_map_meta_equal(meta0, meta1); +} + struct bpf_iter_seq_array_map_info { struct bpf_map *map; void *percpu_value_buf; @@ -625,7 +632,7 @@ static const struct bpf_iter_seq_info iter_seq_info = { static int array_map_btf_id; const struct bpf_map_ops array_map_ops = { - .map_meta_equal = bpf_map_meta_equal, + .map_meta_equal = array_map_meta_equal, .map_alloc_check = array_map_alloc_check, .map_alloc = array_map_alloc, .map_free = array_map_free, diff --git a/kernel/bpf/map_in_map.c b/kernel/bpf/map_in_map.c index e97a22dd3232..39ab0b68cade 100644 --- a/kernel/bpf/map_in_map.c +++ b/kernel/bpf/map_in_map.c @@ -75,8 +75,7 @@ bool bpf_map_meta_equal(const struct bpf_map *meta0, return meta0->map_type == meta1->map_type && meta0->key_size == meta1->key_size && meta0->value_size == meta1->value_size && - meta0->map_flags == meta1->map_flags && - meta0->max_entries == meta1->max_entries; + meta0->map_flags == meta1->map_flags; } void *bpf_map_fd_get_ptr(struct bpf_map *map, diff --git a/net/xdp/xskmap.c b/net/xdp/xskmap.c index f45f29f04151..2a4fd6677155 100644 --- a/net/xdp/xskmap.c +++ b/net/xdp/xskmap.c @@ -254,9 +254,16 @@ void xsk_map_try_sock_delete(struct xsk_map *map, struct xdp_sock *xs, spin_unlock_bh(&map->lock); } +static bool xsk_map_meta_equal(const struct bpf_map *meta0, + const struct bpf_map *meta1) +{ + return meta0->max_entries == meta1->max_entries && + bpf_map_meta_equal(meta0, meta1); +} + static int xsk_map_btf_id; const struct bpf_map_ops xsk_map_ops = { - .map_meta_equal = bpf_map_meta_equal, + .map_meta_equal = xsk_map_meta_equal, .map_alloc = xsk_map_alloc, .map_free = xsk_map_free, .map_get_next_key = xsk_map_get_next_key,