media: uvcvideo: Only save async fh if success

Now we keep a reference to the active fh for any call to uvc_ctrl_set,
regardless if it is an actual set or if it is a just a try or if the
device refused the operation.

We should only keep the file handle if the device actually accepted
applying the operation.

Cc: [email protected]
Fixes: e5225c8 ("media: uvcvideo: Send a control event when a Control Change interrupt arrives")
Suggested-by: Hans de Goede <[email protected]>
Reviewed-by: Hans de Goede <[email protected]>
Reviewed-by: Laurent Pinchart <[email protected]>
Signed-off-by: Ricardo Ribalda <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Laurent Pinchart <[email protected]>
Signed-off-by: Mauro Carvalho Chehab <[email protected]>

Author: ribalda

drivers/media/usb/uvc/uvc_ctrl.c

@@ -1811,7 +1811,10 @@ int uvc_ctrl_begin(struct uvc_video_chain *chain)
 }
 
 static int uvc_ctrl_commit_entity(struct uvc_device *dev,
-	struct uvc_entity *entity, int rollback, struct uvc_control **err_ctrl)
+				  struct uvc_fh *handle,
+				  struct uvc_entity *entity,
+				  int rollback,
+				  struct uvc_control **err_ctrl)
 {
 	struct uvc_control *ctrl;
 	unsigned int i;
@@ -1859,6 +1862,10 @@ static int uvc_ctrl_commit_entity(struct uvc_device *dev,
 				*err_ctrl = ctrl;
 			return ret;
 		}
+
+		if (!rollback && handle &&
+		    ctrl->info.flags & UVC_CTRL_FLAG_ASYNCHRONOUS)
+			ctrl->handle = handle;
 	}
 
 	return 0;
@@ -1895,8 +1902,8 @@ int __uvc_ctrl_commit(struct uvc_fh *handle, int rollback,
 
 	/* Find the control. */
 	list_for_each_entry(entity, &chain->entities, chain) {
-		ret = uvc_ctrl_commit_entity(chain->dev, entity, rollback,
-					     &err_ctrl);
+		ret = uvc_ctrl_commit_entity(chain->dev, handle, entity,
+					     rollback, &err_ctrl);
 		if (ret < 0) {
 			if (ctrls)
 				ctrls->error_idx =
@@ -2046,9 +2053,6 @@ int uvc_ctrl_set(struct uvc_fh *handle,
 	mapping->set(mapping, value,
 		uvc_ctrl_data(ctrl, UVC_CTRL_DATA_CURRENT));
 
-	if (ctrl->info.flags & UVC_CTRL_FLAG_ASYNCHRONOUS)
-		ctrl->handle = handle;
-
 	ctrl->dirty = 1;
 	ctrl->modified = 1;
 	return 0;
@@ -2377,7 +2381,7 @@ int uvc_ctrl_restore_values(struct uvc_device *dev)
 			ctrl->dirty = 1;
 		}
 
-		ret = uvc_ctrl_commit_entity(dev, entity, 0, NULL);
+		ret = uvc_ctrl_commit_entity(dev, NULL, entity, 0, NULL);
 		if (ret < 0)
 			return ret;
 	}