| Message ID | 8357d3a6-f1bc-3631-6ca4-fc78253640f7@sandisk.com (mailing list archive) |
|---|---|
| State | Accepted, archived |
| Delegated to: | Mike Snitzer |
| Headers | show |
On Tue, Nov 15 2016 at 6:32pm -0500, Bart Van Assche <bart.vanassche@sandisk.com> wrote: > It is required to hold the queue lock when calling blk_run_queue_async() > to avoid that a race between blk_run_queue_async() and > blk_cleanup_queue() is triggered. > > Signed-off-by: Bart Van Assche <bart.vanassche@sandisk.com> I picked this patch up earlier today, see: https://git.kernel.org/cgit/linux/kernel/git/device-mapper/linux-dm.git/commit/?h=dm-4.10&id=d15bb3a6467e102e60d954aadda5fb19ce6fd8ec But you your "(theoretical?)", I'd really expected you to have realized an actual the need for this change... Mike > --- > drivers/md/dm-rq.c | 10 ++++++++-- > 1 file changed, 8 insertions(+), 2 deletions(-) > > diff --git a/drivers/md/dm-rq.c b/drivers/md/dm-rq.c > index f9f37ad..7df7948 100644 > --- a/drivers/md/dm-rq.c > +++ b/drivers/md/dm-rq.c > @@ -210,6 +210,9 @@ static void rq_end_stats(struct mapped_device *md, struct request *orig) > */ > static void rq_completed(struct mapped_device *md, int rw, bool run_queue) > { > + struct request_queue *q = md->queue; > + unsigned long flags; > + > atomic_dec(&md->pending[rw]); > > /* nudge anyone waiting on suspend queue */ > @@ -222,8 +225,11 @@ static void rq_completed(struct mapped_device *md, int rw, bool run_queue) > * back into ->request_fn() could deadlock attempting to grab the > * queue lock again. > */ > - if (!md->queue->mq_ops && run_queue) > - blk_run_queue_async(md->queue); > + if (!q->mq_ops && run_queue) { > + spin_lock_irqsave(q->queue_lock, flags); > + blk_run_queue_async(q); > + spin_unlock_irqrestore(q->queue_lock, flags); > + } > > /* > * dm_put() must be at the end of this function. See the comment above > -- > 2.10.1 > > -- > dm-devel mailing list > dm-devel@redhat.com > https://www.redhat.com/mailman/listinfo/dm-devel -- dm-devel mailing list dm-devel@redhat.com https://www.redhat.com/mailman/listinfo/dm-devel
diff --git a/drivers/md/dm-rq.c b/drivers/md/dm-rq.c index f9f37ad..7df7948 100644 --- a/drivers/md/dm-rq.c +++ b/drivers/md/dm-rq.c @@ -210,6 +210,9 @@ static void rq_end_stats(struct mapped_device *md, struct request *orig) */ static void rq_completed(struct mapped_device *md, int rw, bool run_queue) { + struct request_queue *q = md->queue; + unsigned long flags; + atomic_dec(&md->pending[rw]); /* nudge anyone waiting on suspend queue */ @@ -222,8 +225,11 @@ static void rq_completed(struct mapped_device *md, int rw, bool run_queue) * back into ->request_fn() could deadlock attempting to grab the * queue lock again. */ - if (!md->queue->mq_ops && run_queue) - blk_run_queue_async(md->queue); + if (!q->mq_ops && run_queue) { + spin_lock_irqsave(q->queue_lock, flags); + blk_run_queue_async(q); + spin_unlock_irqrestore(q->queue_lock, flags); + } /* * dm_put() must be at the end of this function. See the comment above
It is required to hold the queue lock when calling blk_run_queue_async() to avoid that a race between blk_run_queue_async() and blk_cleanup_queue() is triggered. Signed-off-by: Bart Van Assche <bart.vanassche@sandisk.com> --- drivers/md/dm-rq.c | 10 ++++++++-- 1 file changed, 8 insertions(+), 2 deletions(-)