diff options
author | Ralf Baechle <ralf@linux-mips.org> | 2001-01-10 05:27:25 +0000 |
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committer | Ralf Baechle <ralf@linux-mips.org> | 2001-01-10 05:27:25 +0000 |
commit | c9c06167e7933d93a6e396174c68abf242294abb (patch) | |
tree | d9a8bb30663e9a3405a1ef37ffb62bc14b9f019f /Documentation/SubmittingPatches | |
parent | f79e8cc3c34e4192a3e5ef4cc9c6542fdef703c0 (diff) |
Merge with Linux 2.4.0-test12.
Diffstat (limited to 'Documentation/SubmittingPatches')
-rw-r--r-- | Documentation/SubmittingPatches | 286 |
1 files changed, 286 insertions, 0 deletions
diff --git a/Documentation/SubmittingPatches b/Documentation/SubmittingPatches new file mode 100644 index 000000000..4f48032c7 --- /dev/null +++ b/Documentation/SubmittingPatches @@ -0,0 +1,286 @@ + + 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 -u" +------------ + +Use "diff -u" or "diff -urN" 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). +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= /devel/linux-2.4 + MYFILE= drivers/net/mydriver.c + + cd $SRCTREE + cp $MYFILE $MYFILE.orig + vi $MYFILE # make your change + diff -u $MYFILE.orig $MYFILE > /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 -urN -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. + + +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@transmeta.com. 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. + + + +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. + + + +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 40Kb 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. + + + +----------------------------------- +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 = init_etherdev (NULL, 0); + 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 = init_etherdev (NULL, 0); + 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" + + + |