On Fri, Jun 22, 2012 at 12:20 AM, Bart Van Assche <bvanassche@xxxxxxx> wrote:
> On 06/21/12 21:40, Muthu Kumar wrote:
>
>> On Wed, Jun 20, 2012 at 10:40 PM, Bart Van Assche <bvanassche@xxxxxxx> 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) ?
Perfect. Thanks.
Regards,
Muthu.
>
> From: Muthukumar Ratty <muthur@xxxxxxxxx>
> 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 <muthur@xxxxxxxxx>
> Signed-off-by: Bart Van Assche <bvanassche@xxxxxxx>
> Cc: Tejun Heo <tj@xxxxxxxxxx>
> Cc: Jens Axboe <axboe@xxxxxxxxx>
> Cc: James Bottomley <James.Bottomley@xxxxxxxxxxxxxxxxxxxxx>
> ---
> 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-scsi" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
