performance fix

[ghost]

change for -> while

[KernelPRBot]

Hi @parduscix!

Thanks for your contribution to the Linux kernel!

Linux kernel development happens on mailing lists, rather than on GitHub - this GitHub repository is a read-only mirror that isn't used for accepting contributions. So that your change can become part of Linux, please email it to us as a patch.

Sending patches isn't quite as simple as sending a pull request, but fortunately it is a well documented process.

Here's what to do:

• Format your contribution according to kernel requirements
• Decide who to send your contribution to
• Set up your system to send your contribution as an email
• Send your contribution and wait for feedback

How do I format my contribution?

The Linux kernel community is notoriously picky about how contributions are formatted and sent. Fortunately, they have documented their expectations.

Firstly, all contributions need to be formatted as patches. A patch is a plain text document showing the change you want to make to the code, and documenting why it is a good idea.

You can create patches with git format-patch.

Secondly, patches need 'commit messages', which is the human-friendly documentation explaining what the change is and why it's necessary.

Thirdly, changes have some technical requirements. There is a Linux kernel coding style, and there are licensing requirements you need to comply with.

Both of these are documented in the Submitting Patches documentation that is part of the kernel.

Note that you will almost certainly have to modify your existing git commits to satisfy these requirements. Don't worry: there are many guides on the internet for doing this.

Who do I send my contribution to?

The Linux kernel is composed of a number of subsystems. These subsystems are maintained by different people, and have different mailing lists where they discuss proposed changes.

If you don't already know what subsystem your change belongs to, the get_maintainer.pl script in the kernel source can help you.

get_maintainer.pl will take the patch or patches you created in the previous step, and tell you who is responsible for them, and what mailing lists are used. You can also take a look at the MAINTAINERS file by hand.

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It's not usually necessary to subscribe to the mailing list before you send the patches, but if you're interested in kernel development, subscribing to a subsystem mailing list is a good idea. (At this point, you probably don't need to subscribe to LKML - it is a very high traffic list with about a thousand messages per day, which is often not useful for beginners.)

How do I send my contribution?

Use git send-email, which will ensure that your patches are formatted in the standard manner. In order to use git send-email, you'll need to configure git to use your SMTP email server.

For more information about using git send-email, look at the Git documentation or type git help send-email. There are a number of useful guides and tutorials about git send-email that can be found on the internet.

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If you can't find an answer, there are a few places you can turn:

• Kernel Newbies - this website contains a lot of useful resources for new kernel developers.
• If you'd like a step-by-step, challenge-based introduction to kernel development, the Eudyptula Challenge would be an excellent start.
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I sent my patch - now what?

You wait.

You can check that your email has been received by checking the mailing list archives for the mailing list you sent your patch to. Messages may not be received instantly, so be patient. Kernel developers are generally very busy people, so it may take a few weeks before your patch is looked at.

Then, you keep waiting. Three things may happen:

• You might get a response to your email. Often these will be comments, which may require you to make changes to your patch, or explain why your way is the best way. You should respond to these comments, and you may need to submit another revision of your patch to address the issues raised.
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• Your patch might be ignored completely. This happens sometimes - don't take it personally. Here's what to do:
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  • Try again later. When you resend it, don't add angry commentary, as that will get your patch ignored. It might also get you silently blacklisted.

Further information

• Working with the kernel development community - the official documentation for new kernel contributors

Happy hacking!

This message was posted by a bot - if you have any questions or suggestions, please talk to my owners, @ajdlinux and @daxtens, or raise an issue at https://github.com/ajdlinux/KernelPRBot.

[siyiwolf]

why change while

[zwang001]

Any special gain?

[kalman5]

Also on first iteration i = 1 not 0 as it is with the for

[klingtnet]

Now I know why the kernel development happens in mailing lists, this performance fix is a joke, right?

[mrnirva]

I agree with you

[alexozer]

What the debate about, this seems pretty serious to me? It's a simple change for a simple improvement.

[KamilaBorowska]

This skips i = 0, I believe.