diff options
| author | Jonathan Nieder <jrnieder@gmail.com> | 2011-05-01 06:29:37 -0300 |
|---|---|---|
| committer | Mauro Carvalho Chehab <mchehab@redhat.com> | 2011-05-20 09:29:36 -0300 |
| commit | 1fe70e963028f34ba5e32488a7870ff4b410b19b (patch) | |
| tree | 8185ba45b69831b8cb6a1b1aef5cb84ea092b8cc /drivers/media/video/cx88/cx88-mpeg.c | |
| parent | 8a317a8760cfffa8185b56ff59fb4b6c58488d79 (diff) | |
[media] cx88: fix locking of sub-driver operations
The BKL conversion of this driver seems to have gone wrong.
Loading the cx88-blackbird driver deadlocks.
The cause: mpeg_ops::open in the cx2388x blackbird driver acquires the
device lock and calls the sub-driver's request_acquire, which tries to
acquire the lock again. Fix it by clarifying the semantics of
request_acquire, request_release, advise_acquire, and advise_release:
now all will rely on the caller to acquire the device lock.
Based on work by Ben Hutchings <ben@decadent.org.uk>.
Fixes: https://bugzilla.kernel.org/show_bug.cgi?id=31962
Reported-by: Andi Huber <hobrom@gmx.at>
Tested-by: Andi Huber <hobrom@gmx.at>
Tested-by: Marlon de Boer <marlon@hyves.nl>
Cc: stable@kernel.org
Signed-off-by: Jonathan Nieder <jrnieder@gmail.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
Diffstat (limited to 'drivers/media/video/cx88/cx88-mpeg.c')
| -rw-r--r-- | drivers/media/video/cx88/cx88-mpeg.c | 4 |
1 files changed, 0 insertions, 4 deletions
diff --git a/drivers/media/video/cx88/cx88-mpeg.c b/drivers/media/video/cx88/cx88-mpeg.c index a092c3a4c56..91d3d179c3c 100644 --- a/drivers/media/video/cx88/cx88-mpeg.c +++ b/drivers/media/video/cx88/cx88-mpeg.c @@ -624,13 +624,11 @@ static int cx8802_request_acquire(struct cx8802_driver *drv) if (drv->advise_acquire) { - mutex_lock(&drv->core->lock); core->active_ref++; if (core->active_type_id == CX88_BOARD_NONE) { core->active_type_id = drv->type_id; drv->advise_acquire(drv); } - mutex_unlock(&drv->core->lock); mpeg_dbg(1,"%s() Post acquire GPIO=%x\n", __func__, cx_read(MO_GP0_IO)); } @@ -643,14 +641,12 @@ static int cx8802_request_release(struct cx8802_driver *drv) { struct cx88_core *core = drv->core; - mutex_lock(&drv->core->lock); if (drv->advise_release && --core->active_ref == 0) { drv->advise_release(drv); core->active_type_id = CX88_BOARD_NONE; mpeg_dbg(1,"%s() Post release GPIO=%x\n", __func__, cx_read(MO_GP0_IO)); } - mutex_unlock(&drv->core->lock); return 0; } |