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

[Helge Deller <deller@gmx.de>]

On 5/19/23 16:44, Geert Uytterhoeven wrote:
> Hi Helge,
>
> On Fri, May 19, 2023 at 4:37 PM Helge Deller <deller@gmx.de> wrote:
>> * Geert Uytterhoeven <geert@linux-m68k.org>:
>>> On Tue, May 16, 2023 at 10:23 PM Arnd Bergmann <arnd@kernel.org> wrote:
>>>> From: Arnd Bergmann <arnd@arndb.de>
>>>>
>>>> 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@arndb.de>
>>>
>>>> --- 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@arndb.de>
>> 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@arndb.de>
>> Signed-off-by: Helge Deller <deller@gmx.de>
>>
>> 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