[PATCH v3] staging: most: video: remove redundant cleanup in comp_exit()

[Gabriel Rondon <grondon@gmail.com>]

most_deregister_component() already calls disconnect_channel() for
every linked channel via bus_for_each_dev() in core.c, which invokes
comp_disconnect_channel() to remove each entry from the video_devices
list and tear down the V4L2 device.

The manual cleanup loop in comp_exit() duplicates this work and is
guarded by a stale comment claiming that "mostcore currently doesn't
call disconnect_channel() for linked channels" — but the core has
since been fixed to do exactly that.

Remove the redundant manual cleanup loop, the outdated comment, and
the BUG_ON() assertion that checked for a condition that can no longer
occur.

Signed-off-by: Gabriel Rondon <grondon@gmail.com>
---
Changes since v2:
- Remove the cleanup loop and BUG_ON() entirely instead of replacing
  BUG_ON() with pr_warn(). most_deregister_component() already calls
  disconnect_channel() for every linked channel via bus_for_each_dev()
  in core.c, which handles the teardown. (Greg Kroah-Hartman)

Changes since v1:
- v2 used pr_warn() instead of WARN_ON() to avoid a crash with
  panic-on-warn (Greg Kroah-Hartman). Superseded by the v3 approach
  above.

 drivers/staging/most/video/video.c | 21 ---------------------
 1 file changed, 21 deletions(-)

diff --git a/drivers/staging/most/video/video.c b/drivers/staging/most/video/video.c
index 04351f8ccccf..98988b0d9330 100644
--- a/drivers/staging/most/video/video.c
+++ b/drivers/staging/most/video/video.c
@@ -555,29 +555,8 @@ static int __init comp_init(void)
 
 static void __exit comp_exit(void)
 {
-	struct most_video_dev *mdev, *tmp;
-	LIST_HEAD(free_list);
-
-	/*
-	 * As the mostcore currently doesn't call disconnect_channel()
-	 * for linked channels while we call most_deregister_component()
-	 * we simulate this call here.
-	 * This must be fixed in core.
-	 */
-	spin_lock_irq(&list_lock);
-	list_replace_init(&video_devices, &free_list);
-	spin_unlock_irq(&list_lock);
-
-	list_for_each_entry_safe(mdev, tmp, &free_list, list) {
-		list_del_init(&mdev->list);
-		comp_unregister_videodev(mdev);
-		v4l2_device_disconnect(&mdev->v4l2_dev);
-		v4l2_device_put(&mdev->v4l2_dev);
-	}
-
 	most_deregister_configfs_subsys(&comp);
 	most_deregister_component(&comp);
-	BUG_ON(!list_empty(&video_devices));
 }
 
 module_init(comp_init);
-- 
2.33.0