Hi Sakari,
Thank you for the patch.
On Tuesday 08 Nov 2016 15:55:10 Sakari Ailus wrote:
> This reverts commit 6f0dd24a084a ("[media] media: fix media devnode
> ioctl/syscall and unregister race"). The commit was part of an original
> patchset to avoid crashes when an unregistering device is in use.
>
> Signed-off-by: Sakari Ailus <sakari.ailus@xxxxxxxxxxxxxxx>
For 01/21 to 03/21,
Acked-by: Laurent Pinchart <laurent.pinchart@xxxxxxxxxxxxxxxx>
> ---
> drivers/media/media-device.c | 15 +++++++--------
> drivers/media/media-devnode.c | 8 +-------
> include/media/media-devnode.h | 16 ++--------------
> 3 files changed, 10 insertions(+), 29 deletions(-)
>
> diff --git a/drivers/media/media-device.c b/drivers/media/media-device.c
> index 2783531..f2525eb 100644
> --- a/drivers/media/media-device.c
> +++ b/drivers/media/media-device.c
> @@ -730,7 +730,6 @@ int __must_check __media_device_register(struct
> media_device *mdev, if (ret < 0) {
> /* devnode free is handled in media_devnode_*() */
> mdev->devnode = NULL;
> - media_devnode_unregister_prepare(devnode);
> media_devnode_unregister(devnode);
> return ret;
> }
> @@ -787,9 +786,6 @@ void media_device_unregister(struct media_device *mdev)
> return;
> }
>
> - /* Clear the devnode register bit to avoid races with media dev open
*/
> - media_devnode_unregister_prepare(mdev->devnode);
> -
> /* Remove all entities from the media device */
> list_for_each_entry_safe(entity, next, &mdev->entities,
graph_obj.list)
> __media_device_unregister_entity(entity);
> @@ -810,10 +806,13 @@ void media_device_unregister(struct media_device
> *mdev)
>
> dev_dbg(mdev->dev, "Media device unregistered\n");
>
> - device_remove_file(&mdev->devnode->dev, &dev_attr_model);
> - media_devnode_unregister(mdev->devnode);
> - /* devnode free is handled in media_devnode_*() */
> - mdev->devnode = NULL;
> + /* Check if mdev devnode was registered */
> + if (media_devnode_is_registered(mdev->devnode)) {
> + device_remove_file(&mdev->devnode->dev, &dev_attr_model);
> + media_devnode_unregister(mdev->devnode);
> + /* devnode free is handled in media_devnode_*() */
> + mdev->devnode = NULL;
> + }
> }
> EXPORT_SYMBOL_GPL(media_device_unregister);
>
> diff --git a/drivers/media/media-devnode.c b/drivers/media/media-devnode.c
> index f2772ba..5b605ff 100644
> --- a/drivers/media/media-devnode.c
> +++ b/drivers/media/media-devnode.c
> @@ -287,7 +287,7 @@ int __must_check media_devnode_register(struct
> media_device *mdev, return ret;
> }
>
> -void media_devnode_unregister_prepare(struct media_devnode *devnode)
> +void media_devnode_unregister(struct media_devnode *devnode)
> {
> /* Check if devnode was ever registered at all */
> if (!media_devnode_is_registered(devnode))
> @@ -295,12 +295,6 @@ void media_devnode_unregister_prepare(struct
> media_devnode *devnode)
>
> mutex_lock(&media_devnode_lock);
> clear_bit(MEDIA_FLAG_REGISTERED, &devnode->flags);
> - mutex_unlock(&media_devnode_lock);
> -}
> -
> -void media_devnode_unregister(struct media_devnode *devnode)
> -{
> - mutex_lock(&media_devnode_lock);
> /* Delete the cdev on this minor as well */
> cdev_del(&devnode->cdev);
> mutex_unlock(&media_devnode_lock);
> diff --git a/include/media/media-devnode.h b/include/media/media-devnode.h
> index cd23e91..d55ec2b 100644
> --- a/include/media/media-devnode.h
> +++ b/include/media/media-devnode.h
> @@ -128,26 +128,14 @@ int __must_check media_devnode_register(struct
> media_device *mdev, struct module *owner);
>
> /**
> - * media_devnode_unregister_prepare - clear the media device node register
> bit - * @devnode: the device node to prepare for unregister
> - *
> - * This clears the passed device register bit. Future open calls will be
> met - * with errors. Should be called before media_devnode_unregister() to
> avoid - * races with unregister and device file open calls.
> - *
> - * This function can safely be called if the device node has never been
> - * registered or has already been unregistered.
> - */
> -void media_devnode_unregister_prepare(struct media_devnode *devnode);
> -
> -/**
> * media_devnode_unregister - unregister a media device node
> * @devnode: the device node to unregister
> *
> * This unregisters the passed device. Future open calls will be met with
> * errors.
> *
> - * Should be called after media_devnode_unregister_prepare()
> + * This function can safely be called if the device node has never been
> + * registered or has already been unregistered.
> */
> void media_devnode_unregister(struct media_devnode *devnode);
--
Regards,
Laurent Pinchart
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