This document is almost compliant with ReST notation, but some small adjustments are needed to make it parse properly by Sphinx (mostly, add blank lines where needed). Signed-off-by: Mauro Carvalho Chehab <mchehab@xxxxxxxxxxxxxxxx> --- Documentation/HOWTO | 53 +++++++++++++++++++++++++++++++++++++++++++++++++---- 1 file changed, 49 insertions(+), 4 deletions(-) diff --git a/Documentation/HOWTO b/Documentation/HOWTO index 1f345da28ec5..5a85e3a8112b 100644 --- a/Documentation/HOWTO +++ b/Documentation/HOWTO @@ -1,5 +1,5 @@ HOWTO do Linux kernel development ---------------------------------- +================================= This is the be-all, end-all document on this topic. It contains instructions on how to become a Linux kernel developer and how to learn @@ -28,6 +28,7 @@ kernel development. Assembly (any architecture) is not required unless you plan to do low-level development for that architecture. Though they are not a good substitute for a solid C education and/or years of experience, the following books are good for, if anything, reference: + - "The C Programming Language" by Kernighan and Ritchie [Prentice Hall] - "Practical C Programming" by Steve Oualline [O'Reilly] - "C: A Reference Manual" by Harbison and Steele [Prentice Hall] @@ -64,6 +65,7 @@ people on the mailing lists are not lawyers, and you should not rely on their statements on legal matters. For common questions and answers about the GPL, please see: + http://www.gnu.org/licenses/gpl-faq.html @@ -82,6 +84,7 @@ linux-api@xxxxxxxxxxxxxxx. Here is a list of files that are in the kernel source tree that are required reading: + README This file gives a short background on the Linux kernel and describes what is necessary to do to configure and build the kernel. People @@ -99,30 +102,37 @@ required reading: patches if these rules are followed, and many people will only review code if it is in the proper style. - Documentation/SubmittingPatches - Documentation/SubmittingDrivers + Documentation/SubmittingPatches and Documentation/SubmittingDrivers These files describe in explicit detail how to successfully create and send a patch, including (but not limited to): + - Email contents - Email format - Who to send it to + Following these rules will not guarantee success (as all patches are subject to scrutiny for content and style), but not following them will almost always prevent it. Other excellent descriptions of how to create patches properly are: + "The Perfect Patch" + http://www.ozlabs.org/~akpm/stuff/tpp.txt + "Linux kernel patch submission format" + http://linux.yyz.us/patch-format.html Documentation/stable_api_nonsense.txt This file describes the rationale behind the conscious decision to not have a stable API within the kernel, including things like: + - Subsystem shim-layers (for compatibility?) - Driver portability between Operating Systems. - Mitigating rapid change within the kernel source tree (or preventing rapid change) + This document is crucial for understanding the Linux development philosophy and is very important for people moving to Linux from development on other Operating Systems. @@ -159,10 +169,14 @@ full description of the in-kernel API, and rules on how to handle locking properly. The documents will be created in the Documentation/DocBook/ directory and can be generated as PDF, Postscript, HTML, and man pages by running: + +:: + make pdfdocs make psdocs make htmldocs make mandocs + respectively from the main kernel source directory. @@ -171,7 +185,9 @@ Becoming A Kernel Developer If you do not know anything about Linux kernel development, you should look at the Linux KernelNewbies project: + http://kernelnewbies.org + It consists of a helpful mailing list where you can ask almost any type of basic kernel development question (make sure to search the archives first, before asking something that has already been answered in the @@ -187,7 +203,9 @@ apply a patch. If you do not know where you want to start, but you want to look for some task to start doing to join into the kernel development community, go to the Linux Kernel Janitor's project: + http://kernelnewbies.org/KernelJanitors + It is a great place to start. It describes a list of relatively simple problems that need to be cleaned up and fixed within the Linux kernel source tree. Working with the developers in charge of this project, you @@ -199,6 +217,7 @@ If you already have a chunk of code that you want to put into the kernel tree, but need some help getting it in the proper form, the kernel-mentors project was created to help you out with this. It is a mailing list, and can be found at: + http://selenic.com/mailman/listinfo/kernel-mentors Before making any actual modifications to the Linux kernel code, it is @@ -209,6 +228,7 @@ tools. One such tool that is particularly recommended is the Linux Cross-Reference project, which is able to present source code in a self-referential, indexed webpage format. An excellent up-to-date repository of the kernel code may be found at: + http://lxr.free-electrons.com/ @@ -218,6 +238,7 @@ The development process Linux kernel development process currently consists of a few different main kernel "branches" and lots of different subsystem-specific kernel branches. These different branches are: + - main 4.x kernel tree - 4.x.y -stable kernel tree - 4.x -git kernel patches @@ -229,6 +250,7 @@ branches. These different branches are: 4.x kernels are maintained by Linus Torvalds, and can be found on kernel.org in the pub/linux/kernel/v4.x/ directory. Its development process is as follows: + - As soon as a new kernel is released a two weeks window is open, during this period of time maintainers can submit big diffs to Linus, usually the patches that have already been included in the @@ -253,6 +275,9 @@ process is as follows: It is worth mentioning what Andrew Morton wrote on the linux-kernel mailing list about kernel releases: + +:: + "Nobody knows when a kernel will be released, because it's released according to perceived bug status, not according to a preconceived timeline." @@ -318,6 +343,7 @@ Before updates from subsystem trees are merged into the mainline 4.x tree, they need to be integration-tested. For this purpose, a special testing repository exists into which virtually all subsystem trees are pulled on an almost daily basis: + http://git.kernel.org/?p=linux/kernel/git/next/linux-next.git This way, the -next kernel gives a summary outlook onto what will be @@ -331,6 +357,7 @@ Bug Reporting bugzilla.kernel.org is where the Linux kernel developers track kernel bugs. Users are encouraged to report all bugs that they find in this tool. For details on how to use the kernel bugzilla, please see: + http://bugzilla.kernel.org/page.cgi?id=faq.html The file REPORTING-BUGS in the main kernel source directory has a good @@ -365,10 +392,14 @@ Mailing lists As some of the above documents describe, the majority of the core kernel developers participate on the Linux Kernel Mailing list. Details on how to subscribe and unsubscribe from the list can be found at: + http://vger.kernel.org/vger-lists.html#linux-kernel + There are archives of the mailing list on the web in many different places. Use a search engine to find these archives. For example: + http://dir.gmane.org/gmane.linux.kernel + It is highly recommended that you search the archives about the topic you want to bring up, before you post it to the list. A lot of things already discussed in detail are only recorded at the mailing list @@ -381,11 +412,13 @@ groups. Many of the lists are hosted on kernel.org. Information on them can be found at: + http://vger.kernel.org/vger-lists.html Please remember to follow good behavioral habits when using the lists. Though a bit cheesy, the following URL has some simple guidelines for interacting with the list (or any list): + http://www.albion.com/netiquette/ If multiple people respond to your mail, the CC: list of recipients may @@ -418,6 +451,7 @@ The goal of the kernel community is to provide the best possible kernel there is. When you submit a patch for acceptance, it will be reviewed on its technical merits and those alone. So, what should you be expecting? + - criticism - comments - requests for change @@ -432,6 +466,7 @@ If there are no responses to your posting, wait a few days and try again, sometimes things get lost in the huge volume. What should you not do? + - expect your patch to be accepted without question - become defensive - ignore comments @@ -457,7 +492,9 @@ Differences between the kernel community and corporate structures The kernel community works differently than most traditional corporate development environments. Here are a list of things that you can try to do to avoid problems: + Good things to say regarding your proposed changes: + - "This solves multiple problems." - "This deletes 2000 lines of code." - "Here is a patch that explains what I am trying to describe." @@ -466,6 +503,7 @@ do to avoid problems: - "This increases performance on typical machines..." Bad things you should avoid saying: + - "We did it this way in AIX/ptx/Solaris, so therefore it must be good..." - "I've being doing this for 20 years, so..." @@ -527,12 +565,15 @@ The reasons for breaking things up are the following: and simplify (or simply re-order) patches before submitting them. Here is an analogy from kernel developer Al Viro: + +:: + "Think of a teacher grading homework from a math student. The teacher does not want to see the student's trials and errors before they came up with the solution. They want to see the cleanest, most elegant answer. A good student knows this, and would never submit her intermediate work before the final - solution." + solution. The same is true of kernel development. The maintainers and reviewers do not want to see the thought process behind the @@ -565,6 +606,7 @@ When sending in your patches, pay special attention to what you say in the text in your email. This information will become the ChangeLog information for the patch, and will be preserved for everyone to see for all time. It should describe the patch completely, containing: + - why the change is necessary - the overall design approach in the patch - implementation details @@ -572,7 +614,9 @@ all time. It should describe the patch completely, containing: For more details on what this should all look like, please see the ChangeLog section of the document: + "The Perfect Patch" + http://www.ozlabs.org/~akpm/stuff/tpp.txt @@ -588,6 +632,7 @@ start exactly where you are now. ---------- + Thanks to Paolo Ciarrocchi who allowed the "Development Process" (http://lwn.net/Articles/94386/) section to be based on text he had written, and to Randy Dunlap and Gerrit -- 2.7.4 -- To unsubscribe from this list: send the line "unsubscribe linux-doc" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
