Re: [PATCH] fbdev: fbmem: mark get_fb_unmapped_area() static

[Helge Deller <deller@xxxxxx>]

On 5/19/23 16:44, Geert Uytterhoeven wrote:
> Hi Helge,
>
> On Fri, May 19, 2023 at 4:37 PM Helge Deller <deller@xxxxxx> wrote:
> > * Geert Uytterhoeven <geert@xxxxxxxxxxxxxx>:
> > > On Tue, May 16, 2023 at 10:23 PM Arnd Bergmann <arnd@xxxxxxxxxx> wrote:
> > > > From: Arnd Bergmann <arnd@xxxxxxxx>
> > > >
> > > > There is a global function with this name on sparc, but no
> > > > global declaration:
> > > >
> > > > drivers/video/fbdev/core/fbmem.c:1469:15: error: no previous prototype for 'get_fb_unmapped_area'
> > > >
> > > > Make the generic definition static to avoid this warning. On
> > > > sparc, this is never seen.
> > > >
> > > > Signed-off-by: Arnd Bergmann <arnd@xxxxxxxx>
> > >
> > > > --- a/drivers/video/fbdev/core/fbmem.c
> > > > +++ b/drivers/video/fbdev/core/fbmem.c
> > > > @@ -1468,7 +1468,7 @@ __releases(&info->lock)
> > > >   }
> > > >
> > > >   #if defined(CONFIG_FB_PROVIDE_GET_FB_UNMAPPED_AREA) && !defined(CONFIG_MMU)
> > > > -unsigned long get_fb_unmapped_area(struct file *filp,
> > > > +static unsigned long get_fb_unmapped_area(struct file *filp,
> > > >                                     unsigned long addr, unsigned long len,
> > > >                                     unsigned long pgoff, unsigned long flags)
> > > >   {
> > >
> > > LGTM, as this is unrelated to the SPARC function, and SPARC does
> > > not support nommu (yet? ;-)
> > >
> > > drivers/video/fbdev/Kconfig:config FB_PROVIDE_GET_FB_UNMAPPED_AREA
> > > drivers/video/fbdev/Kconfig-    bool
> > > drivers/video/fbdev/Kconfig-    depends on FB
> > > drivers/video/fbdev/Kconfig-    help
> > > drivers/video/fbdev/Kconfig-      Allow generic frame-buffer to
> > > provide get_fb_unmapped_area
> > > drivers/video/fbdev/Kconfig-      function.
> > >
> > > Probably you want to update this help text, too. E.g.
> > > "to provide shareable character device support on nommu"?
> >
> > I've added Geerts suggestions and made it dependend on !MMU.
> >
> > Applied to fbdev git tree as below.
> >
> > Thanks!
> > Helge
> >
> >
> >  From 9adfa68ca0ddd63007cdce60a8ffcb493bb30d97 Mon Sep 17 00:00:00 2001
> > From: Arnd Bergmann <arnd@xxxxxxxx>
> > Subject: [PATCH] fbdev: fbmem: mark get_fb_unmapped_area() static
> >
> > There is a global function with this name on sparc, but no
> > global declaration:
> >
> > drivers/video/fbdev/core/fbmem.c:1469:15: error: no previous prototype for 'get_fb_unmapped_area'
> >
> > Make the generic definition static to avoid this warning. On
> > sparc, this is never seen.
> >
> > Edit by Helge:
> > Update Kconfig text as suggested by Geert Uytterhoeven and make it dependend on
> > !MMU.
> >
> > Signed-off-by: Arnd Bergmann <arnd@xxxxxxxx>
> > Signed-off-by: Helge Deller <deller@xxxxxx>
> >
> > diff --git a/drivers/video/fbdev/Kconfig b/drivers/video/fbdev/Kconfig
> > index 96e91570cdd3..1688875a07de 100644
> > --- a/drivers/video/fbdev/Kconfig
> > +++ b/drivers/video/fbdev/Kconfig
> > @@ -121,10 +121,10 @@ config FB_SYS_IMAGEBLIT
> >
> >   config FB_PROVIDE_GET_FB_UNMAPPED_AREA
> >          bool
> > -       depends on FB
> > +       depends on FB && !MMU
>
> I expect this to cause a Kconfig warning when enabling DRM_STM
> with MMU=y (e.g. multi_v7_defconfig).
> ARCH_STM32 seems to support both MMU=y and MMU=n.

yes, probably.

I revert that part again, as it's the least invasive change.

Thanks.
Helge