[PATCH] media: uvcvideo: Fix custom control mapping probing

[Ricardo Ribalda <ribalda@chromium.org>]

Custom control mapping introduced a bug, where the filter function was
applied to every single control.

Fix it so it is only applied to the matching controls.

Reported-by: Paul Menzen <pmenzel@molgen.mpg.de>
Closes: https://lore.kernel.org/linux-media/518cd6b4-68a8-4895-b8fc-97d4dae1ddc4@molgen.mpg.de/T/#t
Cc: stable@vger.kernel.org
Fixes: 8f4362a8d42b ("media: uvcvideo: Allow custom control mapping")
Signed-off-by: Ricardo Ribalda <ribalda@chromium.org>
---
Paul, could you check if this fixes your issue, thanks!
---
 drivers/media/usb/uvc/uvc_ctrl.c | 8 +++++---
 1 file changed, 5 insertions(+), 3 deletions(-)

diff --git a/drivers/media/usb/uvc/uvc_ctrl.c b/drivers/media/usb/uvc/uvc_ctrl.c
index 0136df5732ba..06fede57bf36 100644
--- a/drivers/media/usb/uvc/uvc_ctrl.c
+++ b/drivers/media/usb/uvc/uvc_ctrl.c
@@ -2680,6 +2680,10 @@ static void uvc_ctrl_init_ctrl(struct uvc_video_chain *chain,
 	for (i = 0; i < ARRAY_SIZE(uvc_ctrl_mappings); ++i) {
 		const struct uvc_control_mapping *mapping = &uvc_ctrl_mappings[i];
 
+		if (!(uvc_entity_match_guid(ctrl->entity, mapping->entity) &&
+		    ctrl->info.selector == mapping->selector))
+			continue;
+
 		/* Let the device provide a custom mapping. */
 		if (mapping->filter_mapping) {
 			mapping = mapping->filter_mapping(chain, ctrl);
@@ -2687,9 +2691,7 @@ static void uvc_ctrl_init_ctrl(struct uvc_video_chain *chain,
 				continue;
 		}
 
-		if (uvc_entity_match_guid(ctrl->entity, mapping->entity) &&
-		    ctrl->info.selector == mapping->selector)
-			__uvc_ctrl_add_mapping(chain, ctrl, mapping);
+		__uvc_ctrl_add_mapping(chain, ctrl, mapping);
 	}
 }
 

---
base-commit: 68a72104cbcf38ad16500216e213fa4eb21c4be2
change-id: 20240722-fix-filter-mapping-18477dc69048

Best regards,
-- 
Ricardo Ribalda <ribalda@chromium.org>