Re: [PATCH v2 2/3] lib/vsprintf: Split out sprintf() and friends

From: Andy Shevchenko
Date: Tue Aug 08 2023 - 12:50:39 EST


On Mon, Aug 07, 2023 at 10:24:55PM -0400, Steven Rostedt wrote:
> On Mon, 7 Aug 2023 18:09:54 +0300
> Andy Shevchenko <andriy.shevchenko@xxxxxxxxxxxxxxx> wrote:
> > On Mon, Aug 07, 2023 at 05:03:19PM +0200, Petr Mladek wrote:
> > > On Sat 2023-08-05 20:50:26, Andy Shevchenko wrote:
> > > > kernel.h is being used as a dump for all kinds of stuff for a long time.
> > > > sprintf() and friends are used in many drivers without need of the full
> > > > kernel.h dependency train with it.
> > > >
> > > > Here is the attempt on cleaning it up by splitting out sprintf() and
> > > > friends.

...

> > > I agree that kernel.h is not the right place. But are there any
> > > numbers how much separate sprintf.h might safe?
> > > Maybe, we should not reinvent the wheel and get inspired by
> > > userspace.
> > >
> > > sprintf() and friends are basic functions which most people know
> > > from userspace. And it is pretty handy that the kernel variants
> > > are are mostly compatible as well.
> > >
> > > IMHO, it might be handful when they are also included similar way
> > > as in userspace. From my POV printk.h is like stdio.h. And we already
> > > have include/linux/stdarg.h where the v*print*() function might
> > > fit nicely.
> > >
> > > How does this sound, please?
> >
> > Not every user (especially _header_) wants to have printk.h included just for
> > sprintf.h that may have nothing to do with real output. So, same reasoning
> > from me as keeping that in kernel.h, i.e. printk.h no better.
>
> If you separate out the sprintf() into its own header and still include
> that in kernel.h, then for what you said in the other email:
>
> > What to do with _headers_ that include kernel.h for no reason other than
> > sprintf.h (as an example)? Your suggestion, please?
>
> It can include sprintf.h (or printk.h or stdio.h, whatever) instead of kernel.h.
>
> What's the issue?

The issue is the same, printk.h brings a lot more than just s*printf().
Why should I include it for a, let's say, single sprintf() call?

--
With Best Regards,
Andy Shevchenko