Right now, the lock schema for media_device struct is messy,
since sometimes, it is protected via a spin lock, while, for
media graph traversal, it is protected by a mutex.
Solve this conflict by always using a mutex.
As a side effect, this prevents a bug where the media notifiers
were called at atomic context.
Signed-off-by: Mauro Carvalho Chehab <mchehab@xxxxxxxxxxxxxxx>
---
drivers/media/media-device.c | 32 ++++++++++++++------------------
drivers/media/media-entity.c | 16 ++++++++--------
include/media/media-device.h | 6 +-----
3 files changed, 23 insertions(+), 31 deletions(-)
diff --git a/drivers/media/media-device.c b/drivers/media/media-device.c
index 6e43c95629ea..c32fa15cc76e 100644
--- a/drivers/media/media-device.c
+++ b/drivers/media/media-device.c
@@ -90,17 +90,17 @@ static struct media_entity *find_entity(struct media_device *mdev, u32 id)
id &= ~MEDIA_ENT_ID_FLAG_NEXT;
- spin_lock(&mdev->lock);
+ mutex_lock(&mdev->graph_mutex);
media_device_for_each_entity(entity, mdev) {
if (((media_entity_id(entity) == id) && !next) ||
((media_entity_id(entity) > id) && next)) {
- spin_unlock(&mdev->lock);
+ mutex_unlock(&mdev->graph_mutex);
return entity;
}
}
- spin_unlock(&mdev->lock);
+ mutex_unlock(&mdev->graph_mutex);
return NULL;
}
@@ -590,12 +590,12 @@ int __must_check media_device_register_entity(struct media_device *mdev,
if (!ida_pre_get(&mdev->entity_internal_idx, GFP_KERNEL))
return -ENOMEM;
- spin_lock(&mdev->lock);
+ mutex_lock(&mdev->graph_mutex);
ret = ida_get_new_above(&mdev->entity_internal_idx, 1,
&entity->internal_idx);
if (ret < 0) {
- spin_unlock(&mdev->lock);
+ mutex_unlock(&mdev->graph_mutex);
return ret;
}
@@ -615,9 +615,6 @@ int __must_check media_device_register_entity(struct media_device *mdev,
(notify)->notify(entity, notify->notify_data);
}
- spin_unlock(&mdev->lock);
-
- mutex_lock(&mdev->graph_mutex);
if (mdev->entity_internal_idx_max
>= mdev->pm_count_walk.ent_enum.idx_max) {
struct media_entity_graph new = { .top = 0 };
@@ -680,9 +677,9 @@ void media_device_unregister_entity(struct media_entity *entity)
if (mdev == NULL)
return;
- spin_lock(&mdev->lock);
+ mutex_lock(&mdev->graph_mutex);
__media_device_unregister_entity(entity);
- spin_unlock(&mdev->lock);
+ mutex_unlock(&mdev->graph_mutex);
}
EXPORT_SYMBOL_GPL(media_device_unregister_entity);
@@ -703,7 +700,6 @@ void media_device_init(struct media_device *mdev)
INIT_LIST_HEAD(&mdev->pads);
INIT_LIST_HEAD(&mdev->links);
INIT_LIST_HEAD(&mdev->entity_notify);
- spin_lock_init(&mdev->lock);
mutex_init(&mdev->graph_mutex);
ida_init(&mdev->entity_internal_idx);
@@ -752,9 +748,9 @@ EXPORT_SYMBOL_GPL(__media_device_register);
int __must_check media_device_register_entity_notify(struct media_device *mdev,
struct media_entity_notify *nptr)
{
- spin_lock(&mdev->lock);
+ mutex_lock(&mdev->graph_mutex);
list_add_tail(&nptr->list, &mdev->entity_notify);
- spin_unlock(&mdev->lock);
+ mutex_unlock(&mdev->graph_mutex);
return 0;
}
EXPORT_SYMBOL_GPL(media_device_register_entity_notify);
@@ -771,9 +767,9 @@ static void __media_device_unregister_entity_notify(struct media_device *mdev,
void media_device_unregister_entity_notify(struct media_device *mdev,
struct media_entity_notify *nptr)
{
- spin_lock(&mdev->lock);
+ mutex_lock(&mdev->graph_mutex);
__media_device_unregister_entity_notify(mdev, nptr);
- spin_unlock(&mdev->lock);
+ mutex_unlock(&mdev->graph_mutex);
}
EXPORT_SYMBOL_GPL(media_device_unregister_entity_notify);
@@ -787,11 +783,11 @@ void media_device_unregister(struct media_device *mdev)
if (mdev == NULL)
return;
- spin_lock(&mdev->lock);
+ mutex_lock(&mdev->graph_mutex);
/* Check if mdev was ever registered at all */
if (!media_devnode_is_registered(&mdev->devnode)) {
- spin_unlock(&mdev->lock);
+ mutex_unlock(&mdev->graph_mutex);
return;
}
@@ -811,7 +807,7 @@ void media_device_unregister(struct media_device *mdev)
kfree(intf);
}
- spin_unlock(&mdev->lock);
+ mutex_unlock(&mdev->graph_mutex);
device_remove_file(&mdev->devnode.dev, &dev_attr_model);
media_devnode_unregister(&mdev->devnode);
diff --git a/drivers/media/media-entity.c b/drivers/media/media-entity.c
index e95070b3a3d4..c53c1d5589a0 100644
--- a/drivers/media/media-entity.c
+++ b/drivers/media/media-entity.c
@@ -219,7 +219,7 @@ int media_entity_pads_init(struct media_entity *entity, u16 num_pads,
entity->pads = pads;
if (mdev)
- spin_lock(&mdev->lock);
+ mutex_lock(&mdev->graph_mutex);
for (i = 0; i < num_pads; i++) {
pads[i].entity = entity;
@@ -230,7 +230,7 @@ int media_entity_pads_init(struct media_entity *entity, u16 num_pads,
}
if (mdev)
- spin_unlock(&mdev->lock);
+ mutex_unlock(&mdev->graph_mutex);
return 0;
}
@@ -747,9 +747,9 @@ void media_entity_remove_links(struct media_entity *entity)
if (mdev == NULL)
return;
- spin_lock(&mdev->lock);
+ mutex_lock(&mdev->graph_mutex);
__media_entity_remove_links(entity);
- spin_unlock(&mdev->lock);
+ mutex_unlock(&mdev->graph_mutex);
}
EXPORT_SYMBOL_GPL(media_entity_remove_links);
@@ -951,9 +951,9 @@ void media_remove_intf_link(struct media_link *link)
if (mdev == NULL)
return;
- spin_lock(&mdev->lock);
+ mutex_lock(&mdev->graph_mutex);
__media_remove_intf_link(link);
- spin_unlock(&mdev->lock);
+ mutex_unlock(&mdev->graph_mutex);
}
EXPORT_SYMBOL_GPL(media_remove_intf_link);
@@ -975,8 +975,8 @@ void media_remove_intf_links(struct media_interface *intf)
if (mdev == NULL)
return;
- spin_lock(&mdev->lock);
+ mutex_lock(&mdev->graph_mutex);
__media_remove_intf_links(intf);
- spin_unlock(&mdev->lock);
+ mutex_unlock(&mdev->graph_mutex);
}
EXPORT_SYMBOL_GPL(media_remove_intf_links);
diff --git a/include/media/media-device.h b/include/media/media-device.h
index df74cfa7da4a..0c2de97181f3 100644
--- a/include/media/media-device.h
+++ b/include/media/media-device.h
@@ -25,7 +25,6 @@
#include <linux/list.h>
#include <linux/mutex.h>
-#include <linux/spinlock.h>
#include <media/media-devnode.h>
#include <media/media-entity.h>
@@ -304,8 +303,7 @@ struct media_entity_notify {
* @pads: List of registered pads
* @links: List of registered links
* @entity_notify: List of registered entity_notify callbacks
- * @lock: Entities list lock
- * @graph_mutex: Entities graph operation lock
+ * @graph_mutex: Protects access to struct media_device data
* @pm_count_walk: Graph walk for power state walk. Access serialised using
* graph_mutex.
*
@@ -371,8 +369,6 @@ struct media_device {
/* notify callback list invoked when a new entity is registered */
struct list_head entity_notify;
- /* Protects the graph objects creation/removal */
- spinlock_t lock;
/* Serializes graph operations. */
struct mutex graph_mutex;
struct media_entity_graph pm_count_walk;
--
2.5.0
--
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