One of the biggest—and the fastest moving—open source projects, the Linux kernel, is composed of about 53,600 files and nearly 20-million lines of code. With more than 15,600 programmers contributing to the project worldwide, the Linux kernel follows a maintainer model for collaboration.
In this article, I'll provide a quick checklist of steps involved with making your first kernel contribution, and look at what you should know before submitting a patch. For a more in-depth look at the submission process for contributing your first patch, read the [KernelNewbies First Kernel Patch tutorial][1].
### Contributing to the kernel
#### Step 1: Prepare your system.
Steps in this article assume you have the following tools on your system:
+ Text editor
+ Email client
+ Version control system (e.g., git)
#### Step 2: Download the Linux kernel code repository`:`
The subject consists of the path to the file name separated by colons, followed by what the patch does in the imperative tense. After a blank line comes the description of the patch and the mandatory signed off tag and, lastly, a diff of your patch.
### What to know before submitting your first patch
* [Greg Kroah-Hartman][3]'s [staging tree][4] is a good place to submit your [first patch][1] as he accepts easy patches from new contributors. When you get familiar with the patch-sending process, you could send subsystem-specific patches with increased complexity.
* You also could start with correcting coding style issues in the code. To learn more, read the [Linux kernel coding style documentation][5].
* The script [checkpatch.pl][6] detects coding style errors for you. For example, run:
```
perl scripts/checkpatch.pl -f drivers/staging/android/* | less
```
* You could complete TODOs left incomplete by developers:
```
find drivers/staging -name TODO
```
* [Coccinelle][7] is a helpful tool for pattern matching.
* Read the [kernel mailing archives][8].
* Go through the [linux.git log][9] to see commits by previous authors for inspiration.
* Note: Do not top-post to communicate with the reviewer of your patch! Here's an example:
**Wrong way:**
Chris,
_Yes let’s schedule the meeting tomorrow, on the second floor._
> On Fri, Apr 26, 2013 at 9:25 AM, Chris wrote:
> Hey John, I had some questions:
> 1\. Do you want to schedule the meeting tomorrow?
> 2\. On which floor in the office?
> 3\. What time is suitable to you?
(Notice that the last question was unintentionally left unanswered in the reply.)
**Correct way:**
Chris,
See my answers below...
> On Fri, Apr 26, 2013 at 9:25 AM, Chris wrote:
> Hey John, I had some questions:
> 1\. Do you want to schedule the meeting tomorrow?
_Yes tomorrow is fine._
> 2\. On which floor in the office?
_Let's keep it on the second floor._
> 3\. What time is suitable to you?
_09:00 am would be alright._
(All questions were answered, and this way saves reading time.)
* The [Eudyptula challenge][10] is a great way to learn kernel basics.
To learn more, read the [KernelNewbies First Kernel Patch tutorial][1]. After that, if you still have any questions, ask on the [kernelnewbies mailing list][12] or in the [#kernelnewbies IRC channel][13].
