Hi Am 26.04.23 um 16:41 schrieb Geert Uytterhoeven:
Hi Thomas, On Tue, Apr 25, 2023 at 4:28 PM Thomas Zimmermann <tzimmermann@xxxxxxx> wrote:Always return the number of bytes read or written within the framebuffer. Only return an errno code if framebuffer memory was not touched. This is the semantics required by POSIX and makes fb_read() and fb_write() compatible with IGT tests. [1] This bug has been fixed for fb_write() long ago by commit 6a2a88668e90 ("[PATCH] fbdev: Fix return error of fb_write"). The code in fb_read() and the corresponding fb_sys_() helpers was forgotten. Signed-off-by: Thomas Zimmermann <tzimmermann@xxxxxxx> Link: https://gitlab.freedesktop.org/drm/igt-gpu-tools/-/blob/master/tests/fbdev.c # 1Thanks for your patch!--- a/drivers/video/fbdev/core/fbmem.c +++ b/drivers/video/fbdev/core/fbmem.c @@ -820,7 +820,7 @@ fb_read(struct file *file, char __user *buf, size_t count, loff_t *ppos) kfree(buffer); - return (err) ? err : cnt; + return cnt ? cnt : err; }Looks all good to me, so Reviewed-by: Geert Uytterhoeven <geert+renesas@xxxxxxxxx> However, shouldn't the copy_to_user() handling in fb_read() be fixed, too?
That's a good point. It doesn't necessarily copy all given bytes and can thus return the wrong result. The IGT tests passed anyway, but I'll fix it in v2.
Best regards Thomas
Gr{oetje,eeting}s,
Geert
-- 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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