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>
Acked-by: Hans Verkuil <hverkuil-cisco@xxxxxxxxx>
---
drivers/media/mc/mc-device.c | 15 +++++++--------
drivers/media/mc/mc-devnode.c | 8 +-------
include/media/media-devnode.h | 16 ++--------------
3 files changed, 10 insertions(+), 29 deletions(-)
diff --git a/drivers/media/mc/mc-device.c b/drivers/media/mc/mc-device.c
index c0dd4ae57227..6c569ecd4b3d 100644
--- a/drivers/media/mc/mc-device.c
+++ b/drivers/media/mc/mc-device.c
@@ -741,7 +741,6 @@ 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;
}
@@ -797,9 +796,6 @@ 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);
@@ -824,10 +820,13 @@ 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/mc/mc-devnode.c b/drivers/media/mc/mc-devnode.c
index 680fbb3a9340..0ab33214d243 100644
--- a/drivers/media/mc/mc-devnode.c
+++ b/drivers/media/mc/mc-devnode.c
@@ -267,7 +267,7 @@ 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))
@@ -275,12 +275,6 @@ 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_device_del(&devnode->cdev, &devnode->dev);
devnode->media_dev = NULL;
diff --git a/include/media/media-devnode.h b/include/media/media-devnode.h
index d27c1c646c28..46f0d3ae44d1 100644
--- a/include/media/media-devnode.h
+++ b/include/media/media-devnode.h
@@ -115,19 +115,6 @@ int __must_check media_devnode_register(struct media_device *mdev,
struct media_devnode *devnode,
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
@@ -135,7 +122,8 @@ void media_devnode_unregister_prepare(struct media_devnode *devnode);
* 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);
--
2.39.2
