aboutsummaryrefslogtreecommitdiff
path: root/Documentation/SubmittingPatches
diff options
context:
space:
mode:
authorLinus Torvalds <torvalds@ppc970.osdl.org>2005-04-16 15:20:36 -0700
committerLinus Torvalds <torvalds@ppc970.osdl.org>2005-04-16 15:20:36 -0700
commit1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 (patch)
tree0bba044c4ce775e45a88a51686b5d9f90697ea9d /Documentation/SubmittingPatches
downloadlinux-linaro-stable-1da177e4c3f41524e886b7f1b8a0c1fc7321cac2.tar.gz
Linux-2.6.12-rc2v2.6.12-rc2
Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
Diffstat (limited to 'Documentation/SubmittingPatches')
-rw-r--r--Documentation/SubmittingPatches374
1 files changed, 374 insertions, 0 deletions
diff --git a/Documentation/SubmittingPatches b/Documentation/SubmittingPatches
new file mode 100644
index 000000000000..9838d32b2fe7
--- /dev/null
+++ b/Documentation/SubmittingPatches
@@ -0,0 +1,374 @@
+
+ How to Get Your Change Into the Linux Kernel
+ or
+ Care And Operation Of Your Linus Torvalds
+
+
+
+For a person or company who wishes to submit a change to the Linux
+kernel, the process can sometimes be daunting if you're not familiar
+with "the system." This text is a collection of suggestions which
+can greatly increase the chances of your change being accepted.
+
+If you are submitting a driver, also read Documentation/SubmittingDrivers.
+
+
+
+--------------------------------------------
+SECTION 1 - CREATING AND SENDING YOUR CHANGE
+--------------------------------------------
+
+
+
+1) "diff -up"
+------------
+
+Use "diff -up" or "diff -uprN" to create patches.
+
+All changes to the Linux kernel occur in the form of patches, as
+generated by diff(1). When creating your patch, make sure to create it
+in "unified diff" format, as supplied by the '-u' argument to diff(1).
+Also, please use the '-p' argument which shows which C function each
+change is in - that makes the resultant diff a lot easier to read.
+Patches should be based in the root kernel source directory,
+not in any lower subdirectory.
+
+To create a patch for a single file, it is often sufficient to do:
+
+ SRCTREE= linux-2.4
+ MYFILE= drivers/net/mydriver.c
+
+ cd $SRCTREE
+ cp $MYFILE $MYFILE.orig
+ vi $MYFILE # make your change
+ cd ..
+ diff -up $SRCTREE/$MYFILE{.orig,} > /tmp/patch
+
+To create a patch for multiple files, you should unpack a "vanilla",
+or unmodified kernel source tree, and generate a diff against your
+own source tree. For example:
+
+ MYSRC= /devel/linux-2.4
+
+ tar xvfz linux-2.4.0-test11.tar.gz
+ mv linux linux-vanilla
+ wget http://www.moses.uklinux.net/patches/dontdiff
+ diff -uprN -X dontdiff linux-vanilla $MYSRC > /tmp/patch
+ rm -f dontdiff
+
+"dontdiff" is a list of files which are generated by the kernel during
+the build process, and should be ignored in any diff(1)-generated
+patch. dontdiff is maintained by Tigran Aivazian <tigran@veritas.com>
+
+Make sure your patch does not include any extra files which do not
+belong in a patch submission. Make sure to review your patch -after-
+generated it with diff(1), to ensure accuracy.
+
+If your changes produce a lot of deltas, you may want to look into
+splitting them into individual patches which modify things in
+logical stages, this will facilitate easier reviewing by other
+kernel developers, very important if you want your patch accepted.
+There are a number of scripts which can aid in this;
+
+Quilt:
+http://savannah.nongnu.org/projects/quilt
+
+Randy Dunlap's patch scripts:
+http://developer.osdl.org/rddunlap/scripts/patching-scripts.tgz
+
+Andrew Morton's patch scripts:
+http://www.zip.com.au/~akpm/linux/patches/patch-scripts-0.16
+
+2) Describe your changes.
+
+Describe the technical detail of the change(s) your patch includes.
+
+Be as specific as possible. The WORST descriptions possible include
+things like "update driver X", "bug fix for driver X", or "this patch
+includes updates for subsystem X. Please apply."
+
+If your description starts to get long, that's a sign that you probably
+need to split up your patch. See #3, next.
+
+
+
+3) Separate your changes.
+
+Separate each logical change into its own patch.
+
+For example, if your changes include both bug fixes and performance
+enhancements for a single driver, separate those changes into two
+or more patches. If your changes include an API update, and a new
+driver which uses that new API, separate those into two patches.
+
+On the other hand, if you make a single change to numerous files,
+group those changes into a single patch. Thus a single logical change
+is contained within a single patch.
+
+If one patch depends on another patch in order for a change to be
+complete, that is OK. Simply note "this patch depends on patch X"
+in your patch description.
+
+
+4) Select e-mail destination.
+
+Look through the MAINTAINERS file and the source code, and determine
+if your change applies to a specific subsystem of the kernel, with
+an assigned maintainer. If so, e-mail that person.
+
+If no maintainer is listed, or the maintainer does not respond, send
+your patch to the primary Linux kernel developer's mailing list,
+linux-kernel@vger.kernel.org. Most kernel developers monitor this
+e-mail list, and can comment on your changes.
+
+Linus Torvalds is the final arbiter of all changes accepted into the
+Linux kernel. His e-mail address is <torvalds@osdl.org>. He gets
+a lot of e-mail, so typically you should do your best to -avoid- sending
+him e-mail.
+
+Patches which are bug fixes, are "obvious" changes, or similarly
+require little discussion should be sent or CC'd to Linus. Patches
+which require discussion or do not have a clear advantage should
+usually be sent first to linux-kernel. Only after the patch is
+discussed should the patch then be submitted to Linus.
+
+For small patches you may want to CC the Trivial Patch Monkey
+trivial@rustcorp.com.au set up by Rusty Russell; which collects "trivial"
+patches. Trivial patches must qualify for one of the following rules:
+ Spelling fixes in documentation
+ Spelling fixes which could break grep(1).
+ Warning fixes (cluttering with useless warnings is bad)
+ Compilation fixes (only if they are actually correct)
+ Runtime fixes (only if they actually fix things)
+ Removing use of deprecated functions/macros (eg. check_region).
+ Contact detail and documentation fixes
+ Non-portable code replaced by portable code (even in arch-specific,
+ since people copy, as long as it's trivial)
+ Any fix by the author/maintainer of the file. (ie. patch monkey
+ in re-transmission mode)
+
+
+
+5) Select your CC (e-mail carbon copy) list.
+
+Unless you have a reason NOT to do so, CC linux-kernel@vger.kernel.org.
+
+Other kernel developers besides Linus need to be aware of your change,
+so that they may comment on it and offer code review and suggestions.
+linux-kernel is the primary Linux kernel developer mailing list.
+Other mailing lists are available for specific subsystems, such as
+USB, framebuffer devices, the VFS, the SCSI subsystem, etc. See the
+MAINTAINERS file for a mailing list that relates specifically to
+your change.
+
+Even if the maintainer did not respond in step #4, make sure to ALWAYS
+copy the maintainer when you change their code.
+
+For small patches you may want to CC the Trivial Patch Monkey
+trivial@rustcorp.com.au set up by Rusty Russell; which collects "trivial"
+patches. Trivial patches must qualify for one of the following rules:
+ Spelling fixes in documentation
+ Spelling fixes which could break grep(1).
+ Warning fixes (cluttering with useless warnings is bad)
+ Compilation fixes (only if they are actually correct)
+ Runtime fixes (only if they actually fix things)
+ Removing use of deprecated functions/macros (eg. check_region).
+ Contact detail and documentation fixes
+ Non-portable code replaced by portable code (even in arch-specific,
+ since people copy, as long as it's trivial)
+ Any fix by the author/maintainer of the file. (ie. patch monkey
+ in re-transmission mode)
+
+
+
+6) No MIME, no links, no compression, no attachments. Just plain text.
+
+Linus and other kernel developers need to be able to read and comment
+on the changes you are submitting. It is important for a kernel
+developer to be able to "quote" your changes, using standard e-mail
+tools, so that they may comment on specific portions of your code.
+
+For this reason, all patches should be submitting e-mail "inline".
+WARNING: Be wary of your editor's word-wrap corrupting your patch,
+if you choose to cut-n-paste your patch.
+
+Do not attach the patch as a MIME attachment, compressed or not.
+Many popular e-mail applications will not always transmit a MIME
+attachment as plain text, making it impossible to comment on your
+code. A MIME attachment also takes Linus a bit more time to process,
+decreasing the likelihood of your MIME-attached change being accepted.
+
+Exception: If your mailer is mangling patches then someone may ask
+you to re-send them using MIME.
+
+
+
+7) E-mail size.
+
+When sending patches to Linus, always follow step #6.
+
+Large changes are not appropriate for mailing lists, and some
+maintainers. If your patch, uncompressed, exceeds 40 kB in size,
+it is preferred that you store your patch on an Internet-accessible
+server, and provide instead a URL (link) pointing to your patch.
+
+
+
+8) Name your kernel version.
+
+It is important to note, either in the subject line or in the patch
+description, the kernel version to which this patch applies.
+
+If the patch does not apply cleanly to the latest kernel version,
+Linus will not apply it.
+
+
+
+9) Don't get discouraged. Re-submit.
+
+After you have submitted your change, be patient and wait. If Linus
+likes your change and applies it, it will appear in the next version
+of the kernel that he releases.
+
+However, if your change doesn't appear in the next version of the
+kernel, there could be any number of reasons. It's YOUR job to
+narrow down those reasons, correct what was wrong, and submit your
+updated change.
+
+It is quite common for Linus to "drop" your patch without comment.
+That's the nature of the system. If he drops your patch, it could be
+due to
+* Your patch did not apply cleanly to the latest kernel version
+* Your patch was not sufficiently discussed on linux-kernel.
+* A style issue (see section 2),
+* An e-mail formatting issue (re-read this section)
+* A technical problem with your change
+* He gets tons of e-mail, and yours got lost in the shuffle
+* You are being annoying (See Figure 1)
+
+When in doubt, solicit comments on linux-kernel mailing list.
+
+
+
+10) Include PATCH in the subject
+
+Due to high e-mail traffic to Linus, and to linux-kernel, it is common
+convention to prefix your subject line with [PATCH]. This lets Linus
+and other kernel developers more easily distinguish patches from other
+e-mail discussions.
+
+
+
+11) Sign your work
+
+To improve tracking of who did what, especially with patches that can
+percolate to their final resting place in the kernel through several
+layers of maintainers, we've introduced a "sign-off" procedure on
+patches that are being emailed around.
+
+The sign-off is a simple line at the end of the explanation for the
+patch, which certifies that you wrote it or otherwise have the right to
+pass it on as a open-source patch. The rules are pretty simple: if you
+can certify the below:
+
+ Developer's Certificate of Origin 1.0
+
+ By making a contribution to this project, I certify that:
+
+ (a) The contribution was created in whole or in part by me and I
+ have the right to submit it under the open source license
+ indicated in the file; or
+
+ (b) The contribution is based upon previous work that, to the best
+ of my knowledge, is covered under an appropriate open source
+ license and I have the right under that license to submit that
+ work with modifications, whether created in whole or in part
+ by me, under the same open source license (unless I am
+ permitted to submit under a different license), as indicated
+ in the file; or
+
+ (c) The contribution was provided directly to me by some other
+ person who certified (a), (b) or (c) and I have not modified
+ it.
+
+then you just add a line saying
+
+ Signed-off-by: Random J Developer <random@developer.org>
+
+Some people also put extra tags at the end. They'll just be ignored for
+now, but you can do this to mark internal company procedures or just
+point out some special detail about the sign-off.
+
+
+-----------------------------------
+SECTION 2 - HINTS, TIPS, AND TRICKS
+-----------------------------------
+
+This section lists many of the common "rules" associated with code
+submitted to the kernel. There are always exceptions... but you must
+have a really good reason for doing so. You could probably call this
+section Linus Computer Science 101.
+
+
+
+1) Read Documentation/CodingStyle
+
+Nuff said. If your code deviates too much from this, it is likely
+to be rejected without further review, and without comment.
+
+
+
+2) #ifdefs are ugly
+
+Code cluttered with ifdefs is difficult to read and maintain. Don't do
+it. Instead, put your ifdefs in a header, and conditionally define
+'static inline' functions, or macros, which are used in the code.
+Let the compiler optimize away the "no-op" case.
+
+Simple example, of poor code:
+
+ dev = alloc_etherdev (sizeof(struct funky_private));
+ if (!dev)
+ return -ENODEV;
+ #ifdef CONFIG_NET_FUNKINESS
+ init_funky_net(dev);
+ #endif
+
+Cleaned-up example:
+
+(in header)
+ #ifndef CONFIG_NET_FUNKINESS
+ static inline void init_funky_net (struct net_device *d) {}
+ #endif
+
+(in the code itself)
+ dev = alloc_etherdev (sizeof(struct funky_private));
+ if (!dev)
+ return -ENODEV;
+ init_funky_net(dev);
+
+
+
+3) 'static inline' is better than a macro
+
+Static inline functions are greatly preferred over macros.
+They provide type safety, have no length limitations, no formatting
+limitations, and under gcc they are as cheap as macros.
+
+Macros should only be used for cases where a static inline is clearly
+suboptimal [there a few, isolated cases of this in fast paths],
+or where it is impossible to use a static inline function [such as
+string-izing].
+
+'static inline' is preferred over 'static __inline__', 'extern inline',
+and 'extern __inline__'.
+
+
+
+4) Don't over-design.
+
+Don't try to anticipate nebulous future cases which may or may not
+be useful: "Make it as simple as you can, and no simpler"
+
+
+