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| author | Mauro Carvalho Chehab <mchehab@osg.samsung.com> | 2016-04-06 15:55:24 +0200 |
|---|---|---|
| committer | Mauro Carvalho Chehab <mchehab@osg.samsung.com> | 2016-04-20 18:12:02 +0200 |
| commit | e2c91d4d78ee3a69ad634bc7ef90688704baab9d (patch) | |
| tree | d1476d2f4f400d54f06afdc3029f67affd4b3a2b /include/media | |
| parent | [media] m88ds3103: fix undefined division (diff) | |
| download | linux-e2c91d4d78ee3a69ad634bc7ef90688704baab9d.tar.xz linux-e2c91d4d78ee3a69ad634bc7ef90688704baab9d.zip | |
[media] media-device: get rid of the spinlock
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 when the media notifiers
is called at atomic context, while running the notifier callback:
BUG: sleeping function called from invalid context at mm/slub.c:1289
in_atomic(): 1, irqs_disabled(): 0, pid: 3479, name: modprobe
4 locks held by modprobe/3479:
#0: (&dev->mutex){......}, at: [<ffffffff81ce8933>] __driver_attach+0xa3/0x160
#1: (&dev->mutex){......}, at: [<ffffffff81ce8941>] __driver_attach+0xb1/0x160
#2: (register_mutex#5){+.+.+.}, at: [<ffffffffa10596c7>] usb_audio_probe+0x257/0x1c90 [snd_usb_audio]
#3: (&(&mdev->lock)->rlock){+.+.+.}, at: [<ffffffffa0e6051b>] media_device_register_entity+0x1cb/0x700 [media]
CPU: 2 PID: 3479 Comm: modprobe Not tainted 4.5.0-rc3+ #49
Hardware name: /NUC5i7RYB, BIOS RYBDWi35.86A.0350.2015.0812.1722 08/12/2015
0000000000000000 ffff8803b3f6f288 ffffffff81933901 ffff8803c4bae000
ffff8803c4bae5c8 ffff8803b3f6f2b0 ffffffff811c6af5 ffff8803c4bae000
ffffffff8285d7f6 0000000000000509 ffff8803b3f6f2f0 ffffffff811c6ce5
Call Trace:
[<ffffffff81933901>] dump_stack+0x85/0xc4
[<ffffffff811c6af5>] ___might_sleep+0x245/0x3a0
[<ffffffff811c6ce5>] __might_sleep+0x95/0x1a0
[<ffffffff8155aade>] kmem_cache_alloc_trace+0x20e/0x300
[<ffffffffa0e66e3d>] ? media_add_link+0x4d/0x140 [media]
[<ffffffffa0e66e3d>] media_add_link+0x4d/0x140 [media]
[<ffffffffa0e69931>] media_create_pad_link+0xa1/0x600 [media]
[<ffffffffa0fe11b3>] au0828_media_graph_notify+0x173/0x360 [au0828]
[<ffffffffa0e68a6a>] ? media_gobj_create+0x1ba/0x480 [media]
[<ffffffffa0e606fb>] media_device_register_entity+0x3ab/0x700 [media]
Reviewed-by: Javier Martinez Canillas <javier@osg.samsung.com>
Acked-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Acked-by: Hans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@osg.samsung.com>
Diffstat (limited to 'include/media')
| -rw-r--r-- | include/media/media-device.h | 6 |
1 files changed, 1 insertions, 5 deletions
diff --git a/include/media/media-device.h b/include/media/media-device.h index 07809f698464..b21ef244ad3e 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; |