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authorMauro Carvalho Chehab <mchehab@osg.samsung.com>2016-04-06 16:55:24 +0300
committerMauro Carvalho Chehab <mchehab@osg.samsung.com>2016-04-20 19:12:02 +0300
commite2c91d4d78ee3a69ad634bc7ef90688704baab9d (patch)
treed1476d2f4f400d54f06afdc3029f67affd4b3a2b /include/media
parentecb7b0183a89613c154d1bea48b494907efbf8f9 (diff)
downloadlinux-e2c91d4d78ee3a69ad634bc7ef90688704baab9d.tar.xz
[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.h6
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;