This reverts commit c38077d39c7eb84f031b072eab8009acfff57134 that
introduced a deadlock.
[ 2760.127749] INFO: task media-ctl:954 blocked for more than 120 seconds.
[ 2760.131867] Not tainted 4.5.0+ #357
[ 2760.134622] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this
message.
[ 2760.139310] media-ctl D ffffffc000086bcc 0 954 671 0x00000001
[ 2760.143618] Call trace:
[ 2760.145601] [<ffffffc000086bcc>] __switch_to+0x90/0xa4
[ 2760.148941] [<ffffffc0004e6ef0>] __schedule+0x188/0x5b0
[ 2760.152309] [<ffffffc0004e7354>] schedule+0x3c/0xa0
[ 2760.155495] [<ffffffc0004e7768>] schedule_preempt_disabled+0x20/0x38
[ 2760.159423] [<ffffffc0004e8d28>] __mutex_lock_slowpath+0xc4/0x148
[ 2760.163217] [<ffffffc0004e8df0>] mutex_lock+0x44/0x5c
[ 2760.166483] [<ffffffc0003e87d4>] find_entity+0x2c/0xac
[ 2760.169773] [<ffffffc0003e8d34>] __media_device_enum_links+0x20/0x1dc
[ 2760.173711] [<ffffffc0003e9718>] media_device_ioctl+0x214/0x33c
[ 2760.177384] [<ffffffc0003e9eec>] media_ioctl+0x24/0x3c
[ 2760.180671] [<ffffffc0001bee64>] do_vfs_ioctl+0xac/0x758
[ 2760.184026] [<ffffffc0001bf594>] SyS_ioctl+0x84/0x98
[ 2760.187196] [<ffffffc000085d30>] el0_svc_naked+0x24/0x28
Fixes: c38077d39c7e ("[media] media-device: get rid of the spinlock")
Signed-off-by: Laurent Pinchart <laurent.pinchart+rene...@ideasonboard.com>
---
drivers/media/media-device.c | 32 ++++++++++++++++++--------------
drivers/media/media-entity.c | 16 ++++++++--------
include/media/media-device.h | 6 +++++-
3 files changed, 31 insertions(+), 23 deletions(-)
diff --git a/drivers/media/media-device.c b/drivers/media/media-device.c
index c32fa15cc76e..6e43c95629ea 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;
- mutex_lock(&mdev->graph_mutex);
+ spin_lock(&mdev->lock);
media_device_for_each_entity(entity, mdev) {
if (((media_entity_id(entity) == id) && !next) ||
((media_entity_id(entity) > id) && next)) {
- mutex_unlock(&mdev->graph_mutex);
+ spin_unlock(&mdev->lock);
return entity;
}
}
- mutex_unlock(&mdev->graph_mutex);
+ spin_unlock(&mdev->lock);
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;
- mutex_lock(&mdev->graph_mutex);
+ spin_lock(&mdev->lock);
ret = ida_get_new_above(&mdev->entity_internal_idx, 1,
&entity->internal_idx);
if (ret < 0) {
- mutex_unlock(&mdev->graph_mutex);
+ spin_unlock(&mdev->lock);
return ret;
}
@@ -615,6 +615,9 @@ 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 };
@@ -677,9 +680,9 @@ void media_device_unregister_entity(struct media_entity
*entity)
if (mdev == NULL)
return;
- mutex_lock(&mdev->graph_mutex);
+ spin_lock(&mdev->lock);
__media_device_unregister_entity(entity);
- mutex_unlock(&mdev->graph_mutex);
+ spin_unlock(&mdev->lock);
}
EXPORT_SYMBOL_GPL(media_device_unregister_entity);
@@ -700,6 +703,7 @@ 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);
@@ -748,9 +752,9 @@ EXPORT_SYMBOL_GPL(__media_device_register);
int __must_check media_device_register_entity_notify(struct media_device *mdev,
struct media_entity_notify *nptr)
{
- mutex_lock(&mdev->graph_mutex);
+ spin_lock(&mdev->lock);
list_add_tail(&nptr->list, &mdev->entity_notify);
- mutex_unlock(&mdev->graph_mutex);
+ spin_unlock(&mdev->lock);
return 0;
}
EXPORT_SYMBOL_GPL(media_device_register_entity_notify);
@@ -767,9 +771,9 @@ 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)
{
- mutex_lock(&mdev->graph_mutex);
+ spin_lock(&mdev->lock);
__media_device_unregister_entity_notify(mdev, nptr);
- mutex_unlock(&mdev->graph_mutex);
+ spin_unlock(&mdev->lock);
}
EXPORT_SYMBOL_GPL(media_device_unregister_entity_notify);
@@ -783,11 +787,11 @@ void media_device_unregister(struct media_device *mdev)
if (mdev == NULL)
return;
- mutex_lock(&mdev->graph_mutex);
+ spin_lock(&mdev->lock);
/* Check if mdev was ever registered at all */
if (!media_devnode_is_registered(&mdev->devnode)) {
- mutex_unlock(&mdev->graph_mutex);
+ spin_unlock(&mdev->lock);
return;
}
@@ -807,7 +811,7 @@ void media_device_unregister(struct media_device *mdev)
kfree(intf);
}
- mutex_unlock(&mdev->graph_mutex);
+ spin_unlock(&mdev->lock);
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 c53c1d5589a0..e95070b3a3d4 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)
- mutex_lock(&mdev->graph_mutex);
+ spin_lock(&mdev->lock);
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)
- mutex_unlock(&mdev->graph_mutex);
+ spin_unlock(&mdev->lock);
return 0;
}
@@ -747,9 +747,9 @@ void media_entity_remove_links(struct media_entity *entity)
if (mdev == NULL)
return;
- mutex_lock(&mdev->graph_mutex);
+ spin_lock(&mdev->lock);
__media_entity_remove_links(entity);
- mutex_unlock(&mdev->graph_mutex);
+ spin_unlock(&mdev->lock);
}
EXPORT_SYMBOL_GPL(media_entity_remove_links);
@@ -951,9 +951,9 @@ void media_remove_intf_link(struct media_link *link)
if (mdev == NULL)
return;
- mutex_lock(&mdev->graph_mutex);
+ spin_lock(&mdev->lock);
__media_remove_intf_link(link);
- mutex_unlock(&mdev->graph_mutex);
+ spin_unlock(&mdev->lock);
}
EXPORT_SYMBOL_GPL(media_remove_intf_link);
@@ -975,8 +975,8 @@ void media_remove_intf_links(struct media_interface *intf)
if (mdev == NULL)
return;
- mutex_lock(&mdev->graph_mutex);
+ spin_lock(&mdev->lock);
__media_remove_intf_links(intf);
- mutex_unlock(&mdev->graph_mutex);
+ spin_unlock(&mdev->lock);
}
EXPORT_SYMBOL_GPL(media_remove_intf_links);
diff --git a/include/media/media-device.h b/include/media/media-device.h
index b21ef244ad3e..07809f698464 100644
--- a/include/media/media-device.h
+++ b/include/media/media-device.h
@@ -25,6 +25,7 @@
#include <linux/list.h>
#include <linux/mutex.h>
+#include <linux/spinlock.h>
#include <media/media-devnode.h>
#include <media/media-entity.h>
@@ -303,7 +304,8 @@ struct media_entity_notify {
* @pads: List of registered pads
* @links: List of registered links
* @entity_notify: List of registered entity_notify callbacks
- * @graph_mutex: Protects access to struct media_device data
+ * @lock: Entities list lock
+ * @graph_mutex: Entities graph operation lock
* @pm_count_walk: Graph walk for power state walk. Access serialised using
* graph_mutex.
*
@@ -369,6 +371,8 @@ 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;
--
2.7.3
--
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