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[2/2] media: v4l2-async: Safely unregister an non-registered async subdev

Message ID 20210226224938.18166-2-laurent.pinchart@ideasonboard.com (mailing list archive)
State New
Headers show
Series [1/2] list: Add list_is_null() to check if a list_head has been initialized | expand

Commit Message

Laurent Pinchart Feb. 26, 2021, 10:49 p.m. UTC
From: Laurent Pinchart <laurent.pinchart+renesas@ideasonboard.com>

Make the V4L2 async framework a bit more robust by allowing to
unregister a non-registered async subdev. Otherwise the
v4l2_async_cleanup() will attempt to delete the async subdev from the
subdev_list with the corresponding list_head not initialized.

Signed-off-by: Laurent Pinchart <laurent.pinchart+renesas@ideasonboard.com>
---
 drivers/media/v4l2-core/v4l2-async.c | 3 +++
 1 file changed, 3 insertions(+)

Comments

Sakari Ailus March 1, 2021, 8:33 a.m. UTC | #1
Hi Laurent,

On Sat, Feb 27, 2021 at 12:49:38AM +0200, Laurent Pinchart wrote:
> From: Laurent Pinchart <laurent.pinchart+renesas@ideasonboard.com>
> 
> Make the V4L2 async framework a bit more robust by allowing to
> unregister a non-registered async subdev. Otherwise the
> v4l2_async_cleanup() will attempt to delete the async subdev from the
> subdev_list with the corresponding list_head not initialized.
> 
> Signed-off-by: Laurent Pinchart <laurent.pinchart+renesas@ideasonboard.com>

Acked-by: Sakari Ailus <sakari.ailus@linux.intel.com>

IMO this can be merged through another tree once the first patch is agreed
on. Cc Hans and Mauro, too.

> ---
>  drivers/media/v4l2-core/v4l2-async.c | 3 +++
>  1 file changed, 3 insertions(+)
> 
> diff --git a/drivers/media/v4l2-core/v4l2-async.c b/drivers/media/v4l2-core/v4l2-async.c
> index 37cc0263b273..2347b7ac54d4 100644
> --- a/drivers/media/v4l2-core/v4l2-async.c
> +++ b/drivers/media/v4l2-core/v4l2-async.c
> @@ -750,6 +750,9 @@ EXPORT_SYMBOL(v4l2_async_register_subdev);
>  
>  void v4l2_async_unregister_subdev(struct v4l2_subdev *sd)
>  {
> +	if (list_is_null(&sd->async_list))
> +		return;
> +
>  	mutex_lock(&list_lock);
>  
>  	__v4l2_async_notifier_unregister(sd->subdev_notifier);
diff mbox series

Patch

diff --git a/drivers/media/v4l2-core/v4l2-async.c b/drivers/media/v4l2-core/v4l2-async.c
index 37cc0263b273..2347b7ac54d4 100644
--- a/drivers/media/v4l2-core/v4l2-async.c
+++ b/drivers/media/v4l2-core/v4l2-async.c
@@ -750,6 +750,9 @@  EXPORT_SYMBOL(v4l2_async_register_subdev);
 
 void v4l2_async_unregister_subdev(struct v4l2_subdev *sd)
 {
+	if (list_is_null(&sd->async_list))
+		return;
+
 	mutex_lock(&list_lock);
 
 	__v4l2_async_notifier_unregister(sd->subdev_notifier);