Commit 747bda7b authored by Thomas Zimmermann's avatar Thomas Zimmermann
Browse files

fbdev/deferred-io: Provide get_page hook in struct fb_deferred_io 



Add a callback for drivers to provide framebuffer pages to fbdev's
deferred-I/O helpers. Implementations need to acquire a reference on
the page before returning it. Returning NULL generates a SIGBUS
signal.

This will be useful for DRM's fbdev emulation with GEM-shmem buffer
objects.

v2:
- fix typo in commit message (Javier)

Signed-off-by: default avatarThomas Zimmermann <tzimmermann@suse.de>
Reviewed-by: default avatarJavier Martinez Canillas <javierm@redhat.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20240419083331.7761-8-tzimmermann@suse.de
parent 1ecbc7dd

drivers/video/fbdev/core/fb_defio.c

+4 −0
Original line number Diff line number Diff line
@@ -25,9 +25,13 @@ 


static struct page *fb_deferred_io_get_page(struct fb_info *info, unsigned long offs)

{

	struct fb_deferred_io *fbdefio = info->fbdefio;

	const void *screen_buffer = info->screen_buffer;

	struct page *page = NULL;



	if (fbdefio->get_page)

		return fbdefio->get_page(info, offs);



	if (is_vmalloc_addr(screen_buffer + offs))

		page = vmalloc_to_page(screen_buffer + offs);

	else if (info->fix.smem_start)

include/linux/fb.h

+1 −0
Original line number Diff line number Diff line
@@ -225,6 +225,7 @@ struct fb_deferred_io { 
	struct mutex lock; /* mutex that protects the pageref list */

	struct list_head pagereflist; /* list of pagerefs for touched pages */

	/* callback */

	struct page *(*get_page)(struct fb_info *info, unsigned long offset);

	void (*deferred_io)(struct fb_info *info, struct list_head *pagelist);

};

#endif