[PATCH v4 1/5] fbdev: Avoid file argument in fb_pgprotect()

Thomas Zimmermann tzimmermann at suse.de
Fri Sep 22 17:40:55 AEST 2023

Hi Javier

Am 20.09.23 um 10:01 schrieb Javier Martinez Canillas:
> Thomas Zimmermann <tzimmermann at suse.de> writes:
> Hello Thomas,
>> Only PowerPC's fb_pgprotect() needs the file argument, although
>> the implementation does not use it. Pass NULL to the internal
> Can you please mention the function that's the implementation for


> PowerPC ? If I'm looking at the code correctly, that function is
> phys_mem_access_prot() defined in the arch/powerpc/mm/mem.c file:
> pgprot_t phys_mem_access_prot(struct file *file, unsigned long pfn,
> 			      unsigned long size, pgprot_t vma_prot)
> {
> 	if (ppc_md.phys_mem_access_prot)
> 		return ppc_md.phys_mem_access_prot(file, pfn, size, vma_prot);
> 	if (!page_is_ram(pfn))
> 		vma_prot = pgprot_noncached(vma_prot);
> 	return vma_prot;
> }
> and if set, ppc_md.phys_mem_access_prot is pci_phys_mem_access_prot()
> that is defined in the arch/powerpc/kernel/pci-common.c source file:
> https://elixir.bootlin.com/linux/v6.6-rc2/source/arch/powerpc/kernel/pci-common.c#L524

Yes, that's correct. The only value for that function pointer appears to 
be pci_phys_mem_access_prot()

> That function indeed doesn't use the file argument. So your patch looks
> correct to me.
> Reviewed-by: Javier Martinez Canillas <javierm at redhat.com>


Best regards


Thomas Zimmermann
Graphics Driver Developer
SUSE Software Solutions Germany GmbH
Frankenstrasse 146, 90461 Nuernberg, Germany
GF: Ivo Totev, Andrew Myers, Andrew McDonald, Boudien Moerman
HRB 36809 (AG Nuernberg)
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