Hi Am 05.04.23 um 17:53 schrieb Arnd Bergmann:
On Wed, Apr 5, 2023, at 17:05, Thomas Zimmermann wrote:Generic implementations of fb_pgprotect() and fb_is_primary_device() have been in the source code for a long time. Prepare the header file to make use of them. Improve the code by using an inline function for fb_pgprotect() and by removing include statements. Symbols are protected by preprocessor guards. Architectures that provide a symbol need to define a preprocessor token of the same name and value. Otherwise the header file will provide a generic implementation. This pattern has been taken from <asm/io.h>. Signed-off-by: Thomas Zimmermann <tzimmermann@xxxxxxx>Moving this into generic code is good, but I'm not sure about the default for fb_pgprotect():+ +#ifndef fb_pgprotect +#define fb_pgprotect fb_pgprotect +static inline void fb_pgprotect(struct file *file, struct vm_area_struct *vma, + unsigned long off) +{ } +#endifI think most architectures will want the version we have on arc, arm, arm64, loongarch, and sh already: static inline void fb_pgprotect(struct file *file, struct vm_area_struct *vma, unsigned long off) { vma->vm_page_prot = pgprot_writecombine(vma->vm_page_prot); } so I'd suggest making that version the default, and treating the empty ones (m68knommu, sparc32) as architecture specific workarounds.
Make sense, thanks for the feedback. I'll send out an update soon. Best regards Thomas
I see that sparc64 and parisc use pgprot_uncached here, but as
they don't define a custom pgprot_writecombine, this ends up being
the same, and they can use the above definition as well.
mips defines pgprot_writecombine but uses pgprot_noncached
in fb_pgprotect(), which is probably a mistake and should have
been updated as part of commit 4b050ba7a66c ("MIPS: pgtable.h:
Implement the pgprot_writecombine function for MIPS").
Arnd
-- Thomas Zimmermann Graphics Driver Developer SUSE Software Solutions Germany GmbH Maxfeldstr. 5, 90409 Nürnberg, Germany (HRB 36809, AG Nürnberg) Geschäftsführer: Ivo Totev
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