Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1761515Ab2FVHUq (ORCPT ); Fri, 22 Jun 2012 03:20:46 -0400 Received: from relay01ant.iops.be ([212.53.4.34]:46272 "EHLO relay01ant.iops.be" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1761466Ab2FVHUp (ORCPT ); Fri, 22 Jun 2012 03:20:45 -0400 Message-ID: <4FE41CC6.4010406@acm.org> Date: Fri, 22 Jun 2012 07:20:38 +0000 From: Bart Van Assche User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:12.0) Gecko/20120421 Thunderbird/12.0 MIME-Version: 1.0 To: Muthu Kumar CC: Tejun Heo , Jens Axboe , Jej B , linux-kernel@vger.kernel.org, linux-scsi@vger.kernel.org Subject: Re: [PATCH UPDATED] block: In blk_execute_rq_nowait, init rq->end_io before checking for dead queue. References: <4FD345DC.6020405@acm.org> <4FD4DC26.5080902@acm.org> <20120618224253.GH32733@google.com> <4FE21C15.6040409@acm.org> <4FE2B3D1.6070504@acm.org> In-Reply-To: X-Enigmail-Version: 1.5pre Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2791 Lines: 81 On 06/21/12 21:40, Muthu Kumar wrote: > On Wed, Jun 20, 2012 at 10:40 PM, Bart Van Assche wrote: >> On 06/21/12 00:53, Muthu Kumar wrote: >>> This part already went in, its here only for testing - So in the final >>> patch, before applying this should be removed. >> >> When did it go in ? As far as I can see that patch is not yet present in >> Linus' tree nor in James' tree. > > My bad. I thought Jens/James took it already... may be not. Do you agree with combining both patches into one (see below) ? From: Muthukumar Ratty Subject: [PATCH] block: Fix blk_execute_rq_nowait() dead queue handling If the queue is dead blk_execute_rq_nowait() doesn't invoke the done() callback function. That will result in blk_execute_rq() being stuck in wait_for_completion(). Avoid this by initializing rq->end_io to the done() callback before we check the queue state. Also, make sure the queue lock is held around the invocation of the done() callback. Found this through source code review. Signed-off-by: Muthukumar Ratty Signed-off-by: Bart Van Assche Cc: Tejun Heo Cc: Jens Axboe Cc: James Bottomley --- block/blk-exec.c | 11 ++++++++--- 1 files changed, 8 insertions(+), 3 deletions(-) diff --git a/block/blk-exec.c b/block/blk-exec.c index fb2cbd5..8b6dc5b 100644 --- a/block/blk-exec.c +++ b/block/blk-exec.c @@ -43,6 +43,9 @@ static void blk_end_sync_rq(struct request *rq, int error) * Description: * Insert a fully prepared request at the back of the I/O scheduler queue * for execution. Don't wait for completion. + * + * Note: + * This function will invoke @done directly if the queue is dead. */ void blk_execute_rq_nowait(struct request_queue *q, struct gendisk *bd_disk, struct request *rq, int at_head, @@ -51,18 +54,20 @@ void blk_execute_rq_nowait(struct request_queue *q, struct gendisk *bd_disk, int where = at_head ? ELEVATOR_INSERT_FRONT : ELEVATOR_INSERT_BACK; WARN_ON(irqs_disabled()); + + rq->rq_disk = bd_disk; + rq->end_io = done; + spin_lock_irq(q->queue_lock); 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 */ -- 1.7.7 -- 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/