Hi Geert Am 11.04.23 um 10:08 schrieb Geert Uytterhoeven:
Hi Thomas, On Thu, Apr 6, 2023 at 4:30 PM Thomas Zimmermann <tzimmermann@xxxxxxx> 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. The default mode set by fb_pgprotect() is now writecombine, which is what most platforms want. 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>. v2: * use writecombine mappings by default (Arnd) Signed-off-by: Thomas Zimmermann <tzimmermann@xxxxxxx>Thanks for your patch!--- a/include/asm-generic/fb.h +++ b/include/asm-generic/fb.h @@ -1,13 +1,32 @@ /* SPDX-License-Identifier: GPL-2.0 */ + #ifndef __ASM_GENERIC_FB_H_ #define __ASM_GENERIC_FB_H_ -#include <linux/fb.h> -#define fb_pgprotect(...) do {} while (0) +/* + * Only include this header file from your architecture's <asm/fb.h>. + */ + +#include <asm/page.h> + +struct fb_info; +struct file; + +#ifndef fb_pgprotect +#define fb_pgprotect fb_pgprotect +static inline void fb_pgprotect(struct file *file, struct vm_area_struct *vma, + unsigned long off)Does this affect any noMMU platforms that relied on fb_pgprotect() doing nothing before? Perhaps the body below should be protected by "#ifdef CONFIG_MMU"?
I cannot conclusively answer this question, but I did some grep'ing ('git grep ndef | grep CONFIG_MMU'):
Only the architectures in this patchset provide <asm/fb.h> but nothing anywhere uses <asm-generic/fb.h> yet. And of those architectures, only arm and m68k have !CONFIG_MMU cases. Those are handled in the rsp patches. I think we're good.
+{ + vma->vm_page_prot = pgprot_writecombine(vma->vm_page_prot);Shouldn't this use the pgprot_val() wrapper?
No, I think. Grep'ing for vm_page_prot, I'm not seeing it being used in such assignments.
Best regards Thomas
+} +#endifGr{oetje,eeting}s, Geert
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