(cc'ing Lucas) Hi Am 25.03.23 um 08:46 schrieb Sui Jingfeng:
The assignment already done in drm_client_buffer_vmap(), just trival clean, no functional change. Signed-off-by: Sui Jingfeng <15330273260@xxxxxx> --- drivers/gpu/drm/drm_fbdev_generic.c | 5 ++--- 1 file changed, 2 insertions(+), 3 deletions(-) diff --git a/drivers/gpu/drm/drm_fbdev_generic.c b/drivers/gpu/drm/drm_fbdev_generic.c index 4d6325e91565..1da48e71c7f1 100644 --- a/drivers/gpu/drm/drm_fbdev_generic.c +++ b/drivers/gpu/drm/drm_fbdev_generic.c @@ -282,7 +282,7 @@ static int drm_fbdev_damage_blit(struct drm_fb_helper *fb_helper, struct drm_clip_rect *clip) { struct drm_client_buffer *buffer = fb_helper->buffer; - struct iosys_map map, dst; + struct iosys_map map; int ret;/*@@ -302,8 +302,7 @@ static int drm_fbdev_damage_blit(struct drm_fb_helper *fb_helper, if (ret) goto out;- dst = map;- drm_fbdev_damage_blit_real(fb_helper, clip, &dst); + drm_fbdev_damage_blit_real(fb_helper, clip, &map);
I see what you're doing and it's probably correct in this case.But there's a larger issue with this iosys interfaces. Sometimes the address has to be modified (see calls of iosys_map_incr()). That can prevent incorrect uses of the mapping in other places, especially in unmap code.
I think it would make sense to consider a separate structure for the I/O location. The buffer as a whole would still be represented by struct iosys_map. And that new structure, let's call it struct iosys_ptr, would point to an actual location within the buffer's memory range. A few locations and helpers would need changes, but there are not so many callers that it's an issue. This would also allow for a few debugging tests that ensure that iosys_ptr always operates within the bounds of an iosys_map.
I've long considered this idea, but there was no pressure to work on it. Maybe now.
Best regards Thomas
drm_client_buffer_vunmap(buffer);
-- 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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