Messages in this thread | | | Date | Fri, 8 Jun 2012 08:37:41 -0700 | Subject | Re: [PATCH] block: In blk_execute_rq_nowait, init rq->end_io before checking for dead queue. | From | Muthu Kumar <> |
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Tejun, Jens, This is a real problem, right? Should we fix it differently?
Regards, Muthu
On Wed, Jun 6, 2012 at 11:27 PM, Muthu Kumar <muthu.lkml@gmail.com> wrote: > On Wed, Jun 6, 2012 at 11:16 PM, Tejun Heo <tj@kernel.org> wrote: >> Sorry to be nit-picky but Jens would appreciate proper subject and it >> would also be nice to mention the locking change (or even separate >> that into a separate patch). > > No problem. Changed the subject and also added the info about queue > lock in the description. Please check. > > ----------------------- > blk-exec.c: In blk_execute_rq_nowait(), if the queue is dead, call to > done() routine is not made. That will result in blk_execute_rq() stuck > in wait_for_completion(). Avoid this by initializing rq->end_io to > done() routine before we check for dead queue. > > Also, in case of dead queue, call the completion routine with queue->lock held. > > > Signed-off-by: Muthukumar Ratty <muthur@gmail.com> > CC: Tejun Heo <tj@kernel.org> > CC: Jens Axboe <axboe@kernel.dk> > CC: James Bottomley <James.Bottomley@hansenpartnership.com> > > ----------------------- > > diff --git a/block/blk-exec.c b/block/blk-exec.c > index fb2cbd5..284bf56 100644 > --- a/block/blk-exec.c > +++ b/block/blk-exec.c > @@ -53,16 +53,17 @@ void blk_execute_rq_nowait(struct request_queue > *q, struct gendisk *bd_disk, > WARN_ON(irqs_disabled()); > spin_lock_irq(q->queue_lock); > > + rq->rq_disk = bd_disk; > + rq->end_io = done; > + > if (unlikely(blk_queue_dead(q))) { > - spin_unlock_irq(q->queue_lock); > rq->errors = -ENXIO; > if (rq->end_io) > rq->end_io(rq, rq->errors); > + spin_unlock_irq(q->queue_lock); > return; > } > > - rq->rq_disk = bd_disk; > - rq->end_io = done; > __elv_add_request(q, rq, where); > __blk_run_queue(q); > /* the queue is stopped so it won't be run */ > > > ------------------------------------ > > > > > > > >> >> Thanks. >> >> -- >> tejun -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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