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. 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").
I would not want to change any of the other platform's functions unless the rsp platform maintainers ask me to.
Best regards Thomas
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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