diff options
Diffstat (limited to 'Documentation/process')
| -rw-r--r-- | Documentation/process/4.Coding.rst | 8 | ||||
| -rw-r--r-- | Documentation/process/5.Posting.rst | 2 | ||||
| -rw-r--r-- | Documentation/process/changes.rst | 4 | ||||
| -rw-r--r-- | Documentation/process/clang-format.rst | 184 | ||||
| -rw-r--r-- | Documentation/process/coding-style.rst | 17 | ||||
| -rw-r--r-- | Documentation/process/howto.rst | 15 | ||||
| -rw-r--r-- | Documentation/process/kernel-driver-statement.rst | 1 | ||||
| -rw-r--r-- | Documentation/process/license-rules.rst | 20 | ||||
| -rw-r--r-- | Documentation/process/magic-number.rst | 2 | ||||
| -rw-r--r-- | Documentation/process/submitting-patches.rst | 9 |
10 files changed, 232 insertions, 30 deletions
diff --git a/Documentation/process/4.Coding.rst b/Documentation/process/4.Coding.rst index 26b106071364..eb4b185d168c 100644 --- a/Documentation/process/4.Coding.rst +++ b/Documentation/process/4.Coding.rst @@ -58,6 +58,14 @@ can never be transgressed. If there is a good reason to go against the style (a line which becomes far less readable if split to fit within the 80-column limit, for example), just do it. +Note that you can also use the ``clang-format`` tool to help you with +these rules, to quickly re-format parts of your code automatically, +and to review full files in order to spot coding style mistakes, +typos and possible improvements. It is also handy for sorting ``#includes``, +for aligning variables/macros, for reflowing text and other similar tasks. +See the file :ref:`Documentation/process/clang-format.rst <clangformat>` +for more details. + Abstraction layers ****************** diff --git a/Documentation/process/5.Posting.rst b/Documentation/process/5.Posting.rst index 645fa9c7388a..c209d70da66f 100644 --- a/Documentation/process/5.Posting.rst +++ b/Documentation/process/5.Posting.rst @@ -213,7 +213,7 @@ The tags in common use are: which can be found in Documentation/process/submitting-patches.rst. Code without a proper signoff cannot be merged into the mainline. - - Co-Developed-by: states that the patch was also created by another developer + - Co-developed-by: states that the patch was also created by another developer along with the original author. This is useful at times when multiple people work on a single patch. Note, this person also needs to have a Signed-off-by: line in the patch as well. diff --git a/Documentation/process/changes.rst b/Documentation/process/changes.rst index 81cdb528ad46..ddc029734b25 100644 --- a/Documentation/process/changes.rst +++ b/Documentation/process/changes.rst @@ -78,7 +78,7 @@ Binutils -------- The build system has, as of 4.13, switched to using thin archives (`ar T`) -rather than incremental linking (`ld -r`) for built-in.o intermediate steps. +rather than incremental linking (`ld -r`) for built-in.a intermediate steps. This requires binutils 2.20 or newer. Flex @@ -430,7 +430,7 @@ udev FUSE ---- -- <http://sourceforge.net/projects/fuse> +- <https://github.com/libfuse/libfuse/releases> mcelog ------ diff --git a/Documentation/process/clang-format.rst b/Documentation/process/clang-format.rst new file mode 100644 index 000000000000..6710c0707721 --- /dev/null +++ b/Documentation/process/clang-format.rst @@ -0,0 +1,184 @@ +.. _clangformat: + +clang-format +============ + +``clang-format`` is a tool to format C/C++/... code according to +a set of rules and heuristics. Like most tools, it is not perfect +nor covers every single case, but it is good enough to be helpful. + +``clang-format`` can be used for several purposes: + + - Quickly reformat a block of code to the kernel style. Specially useful + when moving code around and aligning/sorting. See clangformatreformat_. + + - Spot style mistakes, typos and possible improvements in files + you maintain, patches you review, diffs, etc. See clangformatreview_. + + - Help you follow the coding style rules, specially useful for those + new to kernel development or working at the same time in several + projects with different coding styles. + +Its configuration file is ``.clang-format`` in the root of the kernel tree. +The rules contained there try to approximate the most common kernel +coding style. They also try to follow :ref:`Documentation/process/coding-style.rst <codingstyle>` +as much as possible. Since not all the kernel follows the same style, +it is possible that you may want to tweak the defaults for a particular +subsystem or folder. To do so, you can override the defaults by writing +another ``.clang-format`` file in a subfolder. + +The tool itself has already been included in the repositories of popular +Linux distributions for a long time. Search for ``clang-format`` in +your repositories. Otherwise, you can either download pre-built +LLVM/clang binaries or build the source code from: + + http://releases.llvm.org/download.html + +See more information about the tool at: + + https://clang.llvm.org/docs/ClangFormat.html + + https://clang.llvm.org/docs/ClangFormatStyleOptions.html + + +.. _clangformatreview: + +Review files and patches for coding style +----------------------------------------- + +By running the tool in its inline mode, you can review full subsystems, +folders or individual files for code style mistakes, typos or improvements. + +To do so, you can run something like:: + + # Make sure your working directory is clean! + clang-format -i kernel/*.[ch] + +And then take a look at the git diff. + +Counting the lines of such a diff is also useful for improving/tweaking +the style options in the configuration file; as well as testing new +``clang-format`` features/versions. + +``clang-format`` also supports reading unified diffs, so you can review +patches and git diffs easily. See the documentation at: + + https://clang.llvm.org/docs/ClangFormat.html#script-for-patch-reformatting + +To avoid ``clang-format`` formatting some portion of a file, you can do:: + + int formatted_code; + // clang-format off + void unformatted_code ; + // clang-format on + void formatted_code_again; + +While it might be tempting to use this to keep a file always in sync with +``clang-format``, specially if you are writing new files or if you are +a maintainer, please note that people might be running different +``clang-format`` versions or not have it available at all. Therefore, +you should probably refrain yourself from using this in kernel sources; +at least until we see if ``clang-format`` becomes commonplace. + + +.. _clangformatreformat: + +Reformatting blocks of code +--------------------------- + +By using an integration with your text editor, you can reformat arbitrary +blocks (selections) of code with a single keystroke. This is specially +useful when moving code around, for complex code that is deeply intended, +for multi-line macros (and aligning their backslashes), etc. + +Remember that you can always tweak the changes afterwards in those cases +where the tool did not do an optimal job. But as a first approximation, +it can be very useful. + +There are integrations for many popular text editors. For some of them, +like vim, emacs, BBEdit and Visual Studio you can find support built-in. +For instructions, read the appropiate section at: + + https://clang.llvm.org/docs/ClangFormat.html + +For Atom, Eclipse, Sublime Text, Visual Studio Code, XCode and other +editors and IDEs you should be able to find ready-to-use plugins. + +For this use case, consider using a secondary ``.clang-format`` +so that you can tweak a few options. See clangformatextra_. + + +.. _clangformatmissing: + +Missing support +--------------- + +``clang-format`` is missing support for some things that are common +in kernel code. They are easy to remember, so if you use the tool +regularly, you will quickly learn to avoid/ignore those. + +In particular, some very common ones you will notice are: + + - Aligned blocks of one-line ``#defines``, e.g.:: + + #define TRACING_MAP_BITS_DEFAULT 11 + #define TRACING_MAP_BITS_MAX 17 + #define TRACING_MAP_BITS_MIN 7 + + vs.:: + + #define TRACING_MAP_BITS_DEFAULT 11 + #define TRACING_MAP_BITS_MAX 17 + #define TRACING_MAP_BITS_MIN 7 + + - Aligned designated initializers, e.g.:: + + static const struct file_operations uprobe_events_ops = { + .owner = THIS_MODULE, + .open = probes_open, + .read = seq_read, + .llseek = seq_lseek, + .release = seq_release, + .write = probes_write, + }; + + vs.:: + + static const struct file_operations uprobe_events_ops = { + .owner = THIS_MODULE, + .open = probes_open, + .read = seq_read, + .llseek = seq_lseek, + .release = seq_release, + .write = probes_write, + }; + + +.. _clangformatextra: + +Extra features/options +---------------------- + +Some features/style options are not enabled by default in the configuration +file in order to minimize the differences between the output and the current +code. In other words, to make the difference as small as possible, +which makes reviewing full-file style, as well diffs and patches as easy +as possible. + +In other cases (e.g. particular subsystems/folders/files), the kernel style +might be different and enabling some of these options may approximate +better the style there. + +For instance: + + - Aligning assignments (``AlignConsecutiveAssignments``). + + - Aligning declarations (``AlignConsecutiveDeclarations``). + + - Reflowing text in comments (``ReflowComments``). + + - Sorting ``#includes`` (``SortIncludes``). + +They are typically useful for block re-formatting, rather than full-file. +You might want to create another ``.clang-format`` file and use that one +from your editor/IDE instead. diff --git a/Documentation/process/coding-style.rst b/Documentation/process/coding-style.rst index a20b44a40ec4..4e7c0a1c427a 100644 --- a/Documentation/process/coding-style.rst +++ b/Documentation/process/coding-style.rst @@ -200,6 +200,15 @@ statement; in the latter case use braces in both branches: otherwise(); } +Also, use braces when a loop contains more than a single simple statement: + +.. code-block:: c + + while (condition) { + if (test) + do_something(); + } + 3.1) Spaces *********** @@ -622,6 +631,14 @@ options ``-kr -i8`` (stands for ``K&R, 8 character indents``), or use re-formatting you may want to take a look at the man page. But remember: ``indent`` is not a fix for bad programming. +Note that you can also use the ``clang-format`` tool to help you with +these rules, to quickly re-format parts of your code automatically, +and to review full files in order to spot coding style mistakes, +typos and possible improvements. It is also handy for sorting ``#includes``, +for aligning variables/macros, for reflowing text and other similar tasks. +See the file :ref:`Documentation/process/clang-format.rst <clangformat>` +for more details. + 10) Kconfig configuration files ------------------------------- diff --git a/Documentation/process/howto.rst b/Documentation/process/howto.rst index c6875b1db56f..3df55811b916 100644 --- a/Documentation/process/howto.rst +++ b/Documentation/process/howto.rst @@ -213,13 +213,6 @@ will learn the basics of getting your patch into the Linux kernel tree, and possibly be pointed in the direction of what to go work on next, if you do not already have an idea. -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: - - https://selenic.com/mailman/listinfo/kernel-mentors - Before making any actual modifications to the Linux kernel code, it is imperative to understand how the code in question works. For this purpose, nothing is better than reading through it directly (most tricky @@ -381,14 +374,6 @@ bugs is one of the best ways to get merits among other developers, because not many people like wasting time fixing other people's bugs. To work in the already reported bug reports, go to https://bugzilla.kernel.org. -If you want to be advised of the future bug reports, you can subscribe to the -bugme-new mailing list (only new bug reports are mailed here) or to the -bugme-janitor mailing list (every change in the bugzilla is mailed here) - - https://lists.linux-foundation.org/mailman/listinfo/bugme-new - - https://lists.linux-foundation.org/mailman/listinfo/bugme-janitors - Mailing lists diff --git a/Documentation/process/kernel-driver-statement.rst b/Documentation/process/kernel-driver-statement.rst index 60d9d868f300..e78452c2164c 100644 --- a/Documentation/process/kernel-driver-statement.rst +++ b/Documentation/process/kernel-driver-statement.rst @@ -103,6 +103,7 @@ today, have in the past, or will in the future. - Auke Kok - Peter Korsgaard - Jiri Kosina + - Aaro Koskinen - Mariusz Kozlowski - Greg Kroah-Hartman - Michael Krufky diff --git a/Documentation/process/license-rules.rst b/Documentation/process/license-rules.rst index 408f77dc6157..8ea26325fe3f 100644 --- a/Documentation/process/license-rules.rst +++ b/Documentation/process/license-rules.rst @@ -4,15 +4,17 @@ Linux kernel licensing rules ============================ The Linux Kernel is provided under the terms of the GNU General Public -License version 2 only (GPL-2.0), as published by the Free Software -Foundation, and provided in the COPYING file. This documentation file is -not meant to replace the COPYING file, but provides a description of how -each source file should be annotated to make the licensing it is governed -under clear and unambiguous. - -The license in the COPYING file applies to the kernel source as a whole, -though individual source files can have a different license which is -required to be compatible with the GPL-2.0:: +License version 2 only (GPL-2.0), as provided in LICENSES/preferred/GPL-2.0, +with an explicit syscall exception described in +LICENSES/exceptions/Linux-syscall-note, as described in the COPYING file. + +This documentation file provides a description of how each source file +should be annotated to make its license clear and unambiguous. +It doesn't replace the Kernel's license. + +The license described in the COPYING file applies to the kernel source +as a whole, though individual source files can have a different license +which is required to be compatible with the GPL-2.0:: GPL-1.0+ : GNU General Public License v1.0 or later GPL-2.0+ : GNU General Public License v2.0 or later diff --git a/Documentation/process/magic-number.rst b/Documentation/process/magic-number.rst index c74199f60c6c..00cecf1fcba9 100644 --- a/Documentation/process/magic-number.rst +++ b/Documentation/process/magic-number.rst @@ -14,7 +14,7 @@ passing pointers to structures via a void * pointer. The tty code, for example, does this frequently to pass driver-specific and line discipline-specific structures back and forth. -The way to use magic numbers is to declare then at the beginning of +The way to use magic numbers is to declare them at the beginning of the structure, like so:: struct tty_ldisc { diff --git a/Documentation/process/submitting-patches.rst b/Documentation/process/submitting-patches.rst index 1ef19d3a3eee..f7152ed565e5 100644 --- a/Documentation/process/submitting-patches.rst +++ b/Documentation/process/submitting-patches.rst @@ -510,8 +510,8 @@ tracking your trees, and to people trying to troubleshoot bugs in your tree. -12) When to use Acked-by: and Cc: ---------------------------------- +12) When to use Acked-by:, Cc:, and Co-Developed-by: +------------------------------------------------------- The Signed-off-by: tag indicates that the signer was involved in the development of the patch, or that he/she was in the patch's delivery path. @@ -543,6 +543,11 @@ person it names - but it should indicate that this person was copied on the patch. This tag documents that potentially interested parties have been included in the discussion. +A Co-Developed-by: states that the patch was also created by another developer +along with the original author. This is useful at times when multiple people +work on a single patch. Note, this person also needs to have a Signed-off-by: +line in the patch as well. + 13) Using Reported-by:, Tested-by:, Reviewed-by:, Suggested-by: and Fixes: -------------------------------------------------------------------------- |