On 1/8/24 12:22, Yueh-Shun Li wrote: > In section "18) Don't re-invent the kernel macros" in "Linux kernel > coding style": > > Recommend reusing macros from headers inside include/linux, instead of > the obsolete include/linux/kernel.h > > Change wording > > - "The header file contains macros" -> "the header files provide macros" > Some macros are intended to use inside the header file only, or are > considered the implementation detail of other facilities. Developers > are expected to determine if a macro is meant to be used outside the > header file. > > Signed-off-by: Yueh-Shun Li <shamrocklee@xxxxxxxxxx> Acked-by: Randy Dunlap <rdunlap@xxxxxxxxxxxxx> Thanks. > --- > Documentation/process/coding-style.rst | 24 +++++++++++++----------- > 1 file changed, 13 insertions(+), 11 deletions(-) > > diff --git a/Documentation/process/coding-style.rst b/Documentation/process/coding-style.rst > index 6db37a46d305..2a5c4f4c568c 100644 > --- a/Documentation/process/coding-style.rst > +++ b/Documentation/process/coding-style.rst > @@ -1048,27 +1048,29 @@ readable alternative if the call-sites have naked true/false constants. > Otherwise limited use of bool in structures and arguments can improve > readability. > > + > 18) Don't re-invent the kernel macros > ------------------------------------- > > -The header file include/linux/kernel.h contains a number of macros that > -you should use, rather than explicitly coding some variant of them yourself. > +The header files in the ``include/linux`` directory provide a number of macros > +that you should use, rather than explicitly coding some variant of them > +yourself. > + > For example, if you need to calculate the length of an array, take advantage > -of the macro > +of the macro ``ARRAY_SIZE()`` from ``include/linux/array_size.h`` by > > .. code-block:: c > > - #define ARRAY_SIZE(x) (sizeof(x) / sizeof((x)[0])) > + #include <linux/array_size.h> > + ARRAY_SIZE(x) // The size of array x > > Similarly, if you need to calculate the size of some structure member, use > +``sizeof_field()`` from ``include/linux/stddef.h``. > > -.. code-block:: c > - > - #define sizeof_field(t, f) (sizeof(((t*)0)->f)) > - > -There are also min() and max() macros that do strict type checking if you > -need them. Feel free to peruse that header file to see what else is already > -defined that you shouldn't reproduce in your code. > +There are also ``min()`` and ``max()`` macros in ``include/linux/minmax.h`` > +that do strict type checking if you need them. Feel free to search across and > +peruse the header files to see what else is already defined that you shouldn't > +reproduce in your code. > > > 19) Editor modelines and other cruft -- #Randy
