Re: [PATCH net] docs: netdev: Document guidance on inline functions

[Simon Horman <horms@kernel.org>]

On Mon, Feb 03, 2025 at 08:50:39PM +0100, Mauro Carvalho Chehab wrote:
> Em Mon, 03 Feb 2025 08:00:56 -0700
> Jonathan Corbet <corbet@lwn.net> escreveu:
> 
> > Simon Horman <horms@kernel.org> writes:
> > 
> > > Document preference for non inline functions in .c files.
> > > This has been the preference for as long as I can recall
> > > and I was recently surprised to discover that it is undocumented.
> > >
> > > Reported-by: Alexandre Ferrieux <alexandre.ferrieux@gmail.com>
> > > Closes: https://lore.kernel.org/all/9662e6fe-cc91-4258-aba1-ab5b016a041a@orange.com/
> > > Signed-off-by: Simon Horman <horms@kernel.org>
> > > ---
> > >  Documentation/process/maintainer-netdev.rst | 11 +++++++++++
> > >  1 file changed, 11 insertions(+)
> > >
> > > diff --git a/Documentation/process/maintainer-netdev.rst b/Documentation/process/maintainer-netdev.rst
> > > index e497729525d5..1fbb8178b8cd 100644
> > > --- a/Documentation/process/maintainer-netdev.rst
> > > +++ b/Documentation/process/maintainer-netdev.rst
> > > @@ -408,6 +408,17 @@ at a greater cost than the value of such clean-ups.
> > >  
> > >  Conversely, spelling and grammar fixes are not discouraged.
> > >  
> > > +Inline functions
> > > +----------------
> > > +
> > > +The use of static inline functions in .c file is strongly discouraged

As suggested by Andrew Lunn elsewhere in this thread I will drop
"static" from the line above.

> > > +unless there is a demonstrable reason for them, usually performance
> > > +related. Rather, it is preferred to omit the inline keyword and allow the
> > > +compiler to inline them as it sees fit.
> 
> You should probably point to chapter (12) of Documentation/process/coding-style.rst
> where it mentions that inline for function prototypes and as a way to
>static  replace macros are OK.

Thanks, perhaps something like this would help:

  Using inline in .h files is fine and is encouraged in place of macros
  [reference section 12].

> 
> > > +
> > > +This is a stricter requirement than that of the general Linux Kernel
> > > +:ref:`Coding Style<codingstyle>`  
> > 
> > I have no objection to this change, but I do wonder if it does indeed
> > belong in the central coding-style document.  I don't think anybody
> > encourages use of "inline" these days...?
> 
> Indeed IMO this belongs to the coding style. I would place it close
> to chapter (12) at Documentation/process/coding-style.rst.

Sure, thanks to you and Jonathan for the positive feedback there.
I will prepare a revised patch that updates coding-style.rst instead.