All the error message types now have a verbose description.
Also there are two new groups of message types:
- Macros, Attributes and Symbols
- Functions and Variables
Rearrange the message types to fit these new groups as needed.
Reviewed-by: Lukas Bulwahn <lukas.bulwahn@xxxxxxxxx>
Signed-off-by: Dwaipayan Ray <dwaipayanray1@xxxxxxxxx>
---
Changes in v4:
- Use lore.kernel.org links
- modify explanation for DEFINE_ARCH_HAS
Changes in v3:
- Add more explanation for LOCKDEP
- Minor grammar fixes
Changes in v2:
- Replace 4.10 kernel doc links by latest
Documentation/dev-tools/checkpatch.rst | 318 ++++++++++++++++++++++---
1 file changed, 280 insertions(+), 38 deletions(-)
diff --git a/Documentation/dev-tools/checkpatch.rst b/Documentation/dev-tools/checkpatch.rst
index 2671e54c8320..51fed1bd72ec 100644
--- a/Documentation/dev-tools/checkpatch.rst
+++ b/Documentation/dev-tools/checkpatch.rst
@@ -280,43 +280,12 @@ API usage
However this is not always the case (See signal.h).
This message type is emitted only for includes from arch/.
- **ARRAY_SIZE**
- The ARRAY_SIZE(foo) macro should be preferred over
- sizeof(foo)/sizeof(foo[0]) for finding number of elements in an
- array.
-
- The macro is defined in include/linux/kernel.h::
-
- #define ARRAY_SIZE(x) (sizeof(x) / sizeof((x)[0]))
-
**AVOID_BUG**
BUG() or BUG_ON() should be avoided totally.
Use WARN() and WARN_ON() instead, and handle the "impossible"
error condition as gracefully as possible.
See: https://www.kernel.org/doc/html/latest/process/deprecated.html#bug-and-bug-on
- **AVOID_EXTERNS**
- Function prototypes don't need to be declared extern in .h
- files. It's assumed by the compiler and is unnecessary.
-
- **AVOID_L_PREFIX**
- Local symbol names that are prefixed with `.L` should be avoided,
- as this has special meaning for the assembler; a symbol entry will
- not be emitted into the symbol table. This can prevent `objtool`
- from generating correct unwind info.
-
- Symbols with STB_LOCAL binding may still be used, and `.L` prefixed
- local symbol names are still generally usable within a function,
- but `.L` prefixed local symbol names should not be used to denote
- the beginning or end of code regions via
- `SYM_CODE_START_LOCAL`/`SYM_CODE_END`
-
- **BIT_MACRO**
- Defines like: 1 << <digit> could be BIT(digit).
- The BIT() macro is defined in include/linux/bitops.h::
-
- #define BIT(nr) (1UL << (nr))
-
**CONSIDER_KSTRTO**
The simple_strtol(), simple_strtoll(), simple_strtoul(), and
simple_strtoull() functions explicitly ignore overflows, which
@@ -325,6 +294,25 @@ API usage
correct replacements.
See: https://www.kernel.org/doc/html/latest/process/deprecated.html#simple-strtol-simple-strtoll-simple-strtoul-simple-strtoull
+ **LOCKDEP**
+ The lockdep_no_validate class was added as a temporary measure to
+ prevent warnings on conversion of device->sem to device->mutex.
+ It should not be used for any other purpose.
+ See: https://lore.kernel.org/lkml/1268959062.9440.467.camel@laptop/
+
+ **MALFORMED_INCLUDE**
+ The #include statement has a malformed path. This has happened
+ because the author has included a double slash "//" in the pathname
+ accidentally.
+
+ **USE_LOCKDEP**
+ lockdep_assert_held() annotations should be preferred over
+ assertions based on spin_is_locked()
+ See: https://www.kernel.org/doc/html/latest/locking/lockdep-design.html#annotations
+
+ **UAPI_INCLUDE**
+ No #include statements in include/uapi should use a uapi/ path.
+
Comment style
-------------
@@ -353,7 +341,6 @@ Comment style
See: https://www.kernel.org/doc/html/latest/process/coding-style.html#commenting
-
Commit message
--------------
@@ -397,6 +384,35 @@ Commit message
source patch.
See: https://www.kernel.org/doc/html/latest/process/submitting-patches.html#sign-your-work-the-developer-s-certificate-of-origin
+ **DIFF_IN_COMMIT_MSG**
+ Avoid having diff content in commit message.
+ This causes problems when one tries to apply a file containing both
+ the changelog and the diff because patch(1) tries to apply the diff
+ which it found in the changelog.
+ See: https://lore.kernel.org/lkml/20150611134006.9df79a893e3636019ad2759e@xxxxxxxxxxxxxxxxxxxx/
+
+ **GERRIT_CHANGE_ID**
+ To be picked up by gerrit, the footer of the commit message might
+ have a Change-Id like::
+
+ Change-Id: Ic8aaa0728a43936cd4c6e1ed590e01ba8f0fbf5b
+ Signed-off-by: A. U. Thor <author@xxxxxxxxxxx>
+
+ The Change-Id line must be removed before submitting.
+
+ **GIT_COMMIT_ID**
+ The proper way to reference a commit id is:
+ commit <12+ chars of sha1> ("<title line>")
+
+ An example may be::
+
+ Commit e21d2170f36602ae2708 ("video: remove unnecessary
+ platform_set_drvdata()") removed the unnecessary
+ platform_set_drvdata(), but left the variable "dev" unused,
+ delete it.
+
+ See: https://www.kernel.org/doc/html/latest/process/submitting-patches.html#describe-your-changes
+
Comparison style
----------------
@@ -426,6 +442,147 @@ Comparison style
side of the test should be avoided.
+Macros, Attributes and Symbols
+------------------------------
+
+ **ARRAY_SIZE**
+ The ARRAY_SIZE(foo) macro should be preferred over
+ sizeof(foo)/sizeof(foo[0]) for finding number of elements in an
+ array.
+
+ The macro is defined in include/linux/kernel.h::
+
+ #define ARRAY_SIZE(x) (sizeof(x) / sizeof((x)[0]))
+
+ **AVOID_EXTERNS**
+ Function prototypes don't need to be declared extern in .h
+ files. It's assumed by the compiler and is unnecessary.
+
+ **AVOID_L_PREFIX**
+ Local symbol names that are prefixed with `.L` should be avoided,
+ as this has special meaning for the assembler; a symbol entry will
+ not be emitted into the symbol table. This can prevent `objtool`
+ from generating correct unwind info.
+
+ Symbols with STB_LOCAL binding may still be used, and `.L` prefixed
+ local symbol names are still generally usable within a function,
+ but `.L` prefixed local symbol names should not be used to denote
+ the beginning or end of code regions via
+ `SYM_CODE_START_LOCAL`/`SYM_CODE_END`
+
+ **BIT_MACRO**
+ Defines like: 1 << <digit> could be BIT(digit).
+ The BIT() macro is defined in include/linux/bitops.h::
+
+ #define BIT(nr) (1UL << (nr))
+
+ **CONST_READ_MOSTLY**
+ When a variable is tagged with the __read_mostly annotation, it is a
+ signal to the compiler that accesses to the variable will be mostly
+ reads and rarely(but NOT never) a write.
+
+ const __read_mostly does not make any sense as const data is already
+ read-only. The __read_mostly annotation thus should be removed.
+
+ **DATE_TIME**
+ It is generally desirable that building the same source code with
+ the same set of tools is reproducible, i.e. the output is always
+ exactly the same.
+
+ The kernel does *not* use the ``__DATE__`` and ``__TIME__`` macros,
+ and enables warnings if they are used as they can lead to
+ non-deterministic builds.
+ See: https://www.kernel.org/doc/html/latest/kbuild/reproducible-builds.html#timestamps
+
+ **DEFINE_ARCH_HAS**
+ The ARCH_HAS_xyz and ARCH_HAVE_xyz patterns are wrong.
+
+ For big conceptual features use Kconfig symbols instead. And for
+ smaller things where we have compatibility fallback functions but
+ want architectures able to override them with optimized ones, we
+ should either use weak functions (appropriate for some cases), or
+ the symbol that protects them should be the same symbol we use.
+ See: https://lore.kernel.org/lkml/CA+55aFycQ9XJvEOsiM3txHL5bjUc8CeKWJNR_H+MiicaddB42Q@xxxxxxxxxxxxxx/
+
+ **INIT_ATTRIBUTE**
+ Const init definitions should use __initconst instead of
+ __initdata.
+
+ Similarly init definitions without const require a separate
+ use of const.
+
+ **INLINE_LOCATION**
+ The inline keyword should sit between storage class and type.
+
+ For example, the following segment::
+
+ inline static int example_function(void)
+ {
+ ...
+ }
+
+ should be::
+
+ static inline int example_function(void)
+ {
+ ...
+ }
+
+ **MULTISTATEMENT_MACRO_USE_DO_WHILE**
+ Macros with multiple statements should be enclosed in a
+ do - while block. Same should also be the case for macros
+ starting with `if` to avoid logic defects::
+
+ #define macrofun(a, b, c) \
+ do { \
+ if (a == 5) \
+ do_this(b, c); \
+ } while (0)
+
+ See: https://www.kernel.org/doc/html/latest/process/coding-style.html#macros-enums-and-rtl
+
+ **WEAK_DECLARATION**
+ Using weak declarations like __attribute__((weak)) or __weak
+ can have unintended link defects. Avoid using them.
+
+
+Functions and Variables
+-----------------------
+
+ **CAMELCASE**
+ Avoid CamelCase Identifiers.
+ See: https://www.kernel.org/doc/html/latest/process/coding-style.html#naming
+
+ **FUNCTION_WITHOUT_ARGS**
+ Function declarations without arguments like::
+
+ int foo()
+
+ should be::
+
+ int foo(void)
+
+ **GLOBAL_INITIALISERS**
+ Global variables should not be initialized explicitly to
+ 0 (or NULL, false, etc.). Your compiler (or rather your
+ loader, which is responsible for zeroing out the relevant
+ sections) automatically does it for you.
+
+ **INITIALISED_STATIC**
+ Static variables should not be initialized explicitly to zero.
+ Your compiler (or rather your loader) automatically does
+ it for you.
+
+ **RETURN_PARENTHESES**
+ return is not a function and as such doesn't need parentheses::
+
+ return (bar);
+
+ can simply be::
+
+ return bar;
+
+
Spacing and Brackets
--------------------
@@ -439,7 +596,7 @@ Spacing and Brackets
and put the closing brace first::
if (x is true) {
- we do y
+ we do y
}
This applies for all non-functional blocks.
@@ -448,7 +605,7 @@ Spacing and Brackets
int function(int x)
{
- body of function
+ body of function
}
See: https://www.kernel.org/doc/html/latest/process/coding-style.html#placing-braces-and-spaces
@@ -485,29 +642,114 @@ Spacing and Brackets
printk(KERN_INFO "bar");
+ **ELSE_AFTER_BRACE**
+ `else {` should follow the closing block `}` on the same line.
+ See: https://www.kernel.org/doc/html/latest/process/coding-style.html#placing-braces-and-spaces
+
**LINE_SPACING**
Vertical space is wasted given the limited number of lines an
editor window can display when multiple blank lines are used.
See: https://www.kernel.org/doc/html/latest/process/coding-style.html#spaces
+ **OPEN_BRACE**
+ The opening brace should be following the function definitions on the
+ next line. For any non-functional block it should be on the same line
+ as the last construct.
+ See: https://www.kernel.org/doc/html/latest/process/coding-style.html#placing-braces-and-spaces
+
+ **POINTER_LOCATION**
+ When using pointer data or a function that returns a pointer type,
+ the preferred use of * is adjacent to the data name or function name
+ and not adjacent to the type name.
+ Examples::
+
+ char *linux_banner;
+ unsigned long long memparse(char *ptr, char **retptr);
+ char *match_strdup(substring_t *s);
+
+ See: https://www.kernel.org/doc/html/latest/process/coding-style.html#spaces
+
**SPACING**
Whitespace style used in the kernel sources is described in kernel docs.
See: https://www.kernel.org/doc/html/latest/process/coding-style.html#spaces
+ **SWITCH_CASE_INDENT_LEVEL**
+ switch should be at the same indent as case.
+ Example::
+
+ switch (suffix) {
+ case 'G':
+ case 'g':
+ mem <<= 30;
+ break;
+ case 'M':
+ case 'm':
+ mem <<= 20;
+ break;
+ case 'K':
+ case 'k':
+ mem <<= 10;
+ /* fall through */
+ default:
+ break;
+ }
+
+ See: https://www.kernel.org/doc/html/latest/process/coding-style.html#indentation
+
**TRAILING_WHITESPACE**
Trailing whitespace should always be removed.
Some editors highlight the trailing whitespace and cause visual
distractions when editing files.
See: https://www.kernel.org/doc/html/latest/process/coding-style.html#spaces
+ **WHILE_AFTER_BRACE**
+ while should follow the closing bracket on the same line::
+
+ do {
+ ...
+ } while(something);
+
+ See: https://www.kernel.org/doc/html/latest/process/coding-style.html#placing-braces-and-spaces
+
Others
------
- **CAMELCASE**
- Avoid CamelCase Identifiers.
- See: https://www.kernel.org/doc/html/latest/process/coding-style.html#naming
-
**CONFIG_DESCRIPTION**
Kconfig symbols should have a help text which fully describes
it.
+
+ **CORRUPTED_PATCH**
+ The patch seems to be corrupted or lines are wrapped.
+ Please regenerate the patch file before sending it to the maintainer.
+
+ **DOS_LINE_ENDINGS**
+ For DOS-formatted patches, there are extra ^M symbols at the end of
+ the line. These should be removed.
+
+ **EXECUTE_PERMISSIONS**
+ There is no reason for source files to be executable. The executable
+ bit can be removed safely.
+
+ **NON_OCTAL_PERMISSIONS**
+ Permission bits should use 4 digit octal permissions (like 0700 or 0444).
+ Avoid using any other base like decimal.
+
+ **NOT_UNIFIED_DIFF**
+ The patch file does not appear to be in unified-diff format. Please
+ regenerate the patch file before sending it to the maintainer.
+
+ **PRINTF_0XDECIMAL**
+ Prefixing 0x with decimal output is defective and should be corrected.
+
+ **TRAILING_STATEMENTS**
+ Trailing statements (for example after any conditional) should be
+ on the next line.
+ Like::
+
+ if (x == y) break;
+
+ should be::
+
+ if (x == y)
+ break;
--
2.30.0
