Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1761329Ab2FHPho (ORCPT ); Fri, 8 Jun 2012 11:37:44 -0400 Received: from mail-vc0-f174.google.com ([209.85.220.174]:58906 "EHLO mail-vc0-f174.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1757781Ab2FHPhm convert rfc822-to-8bit (ORCPT ); Fri, 8 Jun 2012 11:37:42 -0400 MIME-Version: 1.0 In-Reply-To: References: Date: Fri, 8 Jun 2012 08:37:41 -0700 Message-ID: Subject: Re: [PATCH] block: In blk_execute_rq_nowait, init rq->end_io before checking for dead queue. From: Muthu Kumar To: Tejun Heo Cc: Jens Axboe , James.Bottomley@hansenpartnership.com, linux-kernel@vger.kernel.org Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 8BIT Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2317 Lines: 77 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 wrote: > On Wed, Jun 6, 2012 at 11:16 PM, Tejun Heo 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 > CC: Tejun Heo > CC: Jens Axboe > CC: James Bottomley > > ----------------------- > > 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/