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| author |   Li Dongyang <lidongyang@novell.com> | 2011-09-14 14:02:40 +0800 |
|---|---|---|
| committer |   Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> | 2011-10-13 09:48:32 -0400 |
| commit | 69ef68cef961a934c35308843a04b26d91cad4a8 (patch) | |
| tree | bf7bebecdcd53aa75f80fb1e066f2293a2483916 /drivers/block | |
| parent | xen-blkfront: Handle discard requests. (diff) | |
| download | linux-dev-69ef68cef961a934c35308843a04b26d91cad4a8.tar.xz linux-dev-69ef68cef961a934c35308843a04b26d91cad4a8.zip | |
xen-blkfront: fix a deadlock while handling discard response
When we get -EOPNOTSUPP response for a discard request, we will clear
the discard flag on the request queue so we won't attempt to send discard
requests to backend again, and this should be protected under rq->queue_lock.
However, when we setup the request queue, we pass blkif_io_lock to
blk_init_queue so rq->queue_lock is blkif_io_lock indeed, and this lock
is already taken when we are in blkif_interrpt, so remove the
spin_lock/spin_unlock when we clear the discard flag or we will end up
with deadlock here
Signed-off-by: Li Dongyang <lidongyang@novell.com>
[v1: Updated description a bit and removed comment from source]
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Diffstat (limited to 'drivers/block')
| -rw-r--r-- | drivers/block/xen-blkfront.c | 2 |
1 files changed, 0 insertions, 2 deletions
diff --git a/drivers/block/xen-blkfront.c b/drivers/block/xen-blkfront.c index 52076b0d0326..7d1487760283 100644 --- a/drivers/block/xen-blkfront.c +++ b/drivers/block/xen-blkfront.c @@ -747,9 +747,7 @@ static irqreturn_t blkif_interrupt(int irq, void *dev_id) info->gd->disk_name); error = -EOPNOTSUPP; info->feature_discard = 0; - spin_lock(rq->queue_lock); queue_flag_clear(QUEUE_FLAG_DISCARD, rq); - spin_unlock(rq->queue_lock); } __blk_end_request_all(req, error); break; |