diff mbox series

[RFC,01/10] media: v4l: async: Return async sub-devices to subnotifier list

Message ID 20230307212038.968381-2-sakari.ailus@linux.intel.com
State Accepted
Commit 5276c9df9c2ab9a43b534bfb56bdb10899cd3a22
Headers show
Series Separate links and async sub-devices | expand

Commit Message

Sakari Ailus March 7, 2023, 9:20 p.m. UTC 
When an async notifier is unregistered, the async sub-devices in the
notifier's done list will disappear with the notifier. However this is
currently also done to the sub-notifiers that remain registered. Their
sub-devices only need to be unbound while the async sub-devices themselves
need to be returned to the sub-notifier's waiting list. Do this now.

Fixes: 2cab00bb076b ("media: v4l: async: Allow binding notifiers to sub-devices")
Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>
---
 drivers/media/v4l2-core/v4l2-async.c | 13 ++++++++-----
 1 file changed, 8 insertions(+), 5 deletions(-)

Comments

Sakari Ailus March 23, 2023, 8:18 p.m. UTC | #1 
Hi Jacopo,

On Wed, Mar 22, 2023 at 01:56:54PM +0100, Jacopo Mondi wrote:
> Hi Sakari
> 
> On Tue, Mar 07, 2023 at 11:20:29PM +0200, Sakari Ailus wrote:
> > When an async notifier is unregistered, the async sub-devices in the
> > notifier's done list will disappear with the notifier. However this is
> > currently also done to the sub-notifiers that remain registered. Their
> > sub-devices only need to be unbound while the async sub-devices themselves
> > need to be returned to the sub-notifier's waiting list. Do this now.
> 
> I'm a bit missing the point of re-adding the async sub-device to the
> waiting list if the sub-notifier is about to be un-registered as well.

The point is that that's not known. The main notifier may come back,
without the sub-notifier being removed. Those sub-devices only should be
removed with the sub-notifier.

> 
> The only use I found is printing out the list of pending async
> subdevices. Why is this relevant for sub-notifiers only ?

The current model assumes that the main notifier is always removed first of
all notifiers. That should of course be changed but it's much more than a
simple bugfix.
diff mbox series

Patch

diff --git a/drivers/media/v4l2-core/v4l2-async.c b/drivers/media/v4l2-core/v4l2-async.c
index 2f1b718a9189..008a2a3e312e 100644
--- a/drivers/media/v4l2-core/v4l2-async.c
+++ b/drivers/media/v4l2-core/v4l2-async.c
@@ -414,7 +414,8 @@  static void v4l2_async_cleanup(struct v4l2_subdev *sd)
 
 /* Unbind all sub-devices in the notifier tree. */
 static void
-v4l2_async_nf_unbind_all_subdevs(struct v4l2_async_notifier *notifier)
+v4l2_async_nf_unbind_all_subdevs(struct v4l2_async_notifier *notifier,
+				 bool readd)
 {
 	struct v4l2_subdev *sd, *tmp;
 
@@ -423,9 +424,11 @@  v4l2_async_nf_unbind_all_subdevs(struct v4l2_async_notifier *notifier)
 			v4l2_async_find_subdev_notifier(sd);
 
 		if (subdev_notifier)
-			v4l2_async_nf_unbind_all_subdevs(subdev_notifier);
+			v4l2_async_nf_unbind_all_subdevs(subdev_notifier, true);
 
 		v4l2_async_nf_call_unbind(notifier, sd, sd->asd);
+		if (readd)
+			list_add_tail(&sd->asd->list, &notifier->waiting);
 		v4l2_async_cleanup(sd);
 
 		list_move(&sd->async_list, &subdev_list);
@@ -557,7 +560,7 @@  static int __v4l2_async_nf_register(struct v4l2_async_notifier *notifier)
 	/*
 	 * On failure, unbind all sub-devices registered through this notifier.
 	 */
-	v4l2_async_nf_unbind_all_subdevs(notifier);
+	v4l2_async_nf_unbind_all_subdevs(notifier, false);
 
 err_unlock:
 	mutex_unlock(&list_lock);
@@ -607,7 +610,7 @@  __v4l2_async_nf_unregister(struct v4l2_async_notifier *notifier)
 	if (!notifier || (!notifier->v4l2_dev && !notifier->sd))
 		return;
 
-	v4l2_async_nf_unbind_all_subdevs(notifier);
+	v4l2_async_nf_unbind_all_subdevs(notifier, false);
 
 	notifier->sd = NULL;
 	notifier->v4l2_dev = NULL;
@@ -805,7 +808,7 @@  int v4l2_async_register_subdev(struct v4l2_subdev *sd)
 	 */
 	subdev_notifier = v4l2_async_find_subdev_notifier(sd);
 	if (subdev_notifier)
-		v4l2_async_nf_unbind_all_subdevs(subdev_notifier);
+		v4l2_async_nf_unbind_all_subdevs(subdev_notifier, false);
 
 	if (sd->asd)
 		v4l2_async_nf_call_unbind(notifier, sd, sd->asd);