On 10/27/2016 12:53 AM, Bart Van Assche wrote:
> Most blk_mq_requeue_request() and blk_mq_add_to_requeue_list() calls
> are followed by kicking the requeue list. Hence add an argument to
> these two functions that allows to kick the requeue list. This was
> proposed by Christoph Hellwig.
>
> Signed-off-by: Bart Van Assche <bart.vanassche@xxxxxxxxxxx>
> Cc: Christoph Hellwig <hch@xxxxxx>
> Cc: Hannes Reinecke <hare@xxxxxxxx>
> Cc: Sagi Grimberg <sagi@xxxxxxxxxxx>
> Cc: Johannes Thumshirn <jthumshirn@xxxxxxx>
> ---
> block/blk-flush.c | 5 +----
> block/blk-mq.c | 10 +++++++---
> drivers/block/xen-blkfront.c | 2 +-
> drivers/md/dm-rq.c | 2 +-
> drivers/nvme/host/core.c | 2 +-
> drivers/scsi/scsi_lib.c | 4 +---
> include/linux/blk-mq.h | 5 +++--
> 7 files changed, 15 insertions(+), 15 deletions(-)
>
> diff --git a/block/blk-flush.c b/block/blk-flush.c
> index 6a14b68..a834aed 100644
> --- a/block/blk-flush.c
> +++ b/block/blk-flush.c
> @@ -134,10 +134,7 @@ static void blk_flush_restore_request(struct request *rq)
> static bool blk_flush_queue_rq(struct request *rq, bool add_front)
> {
> if (rq->q->mq_ops) {
> - struct request_queue *q = rq->q;
> -
> - blk_mq_add_to_requeue_list(rq, add_front);
> - blk_mq_kick_requeue_list(q);
> + blk_mq_add_to_requeue_list(rq, add_front, true);
> return false;
> } else {
> if (add_front)
> diff --git a/block/blk-mq.c b/block/blk-mq.c
> index 4945437..688bcc3 100644
> --- a/block/blk-mq.c
> +++ b/block/blk-mq.c
> @@ -492,12 +492,12 @@ static void __blk_mq_requeue_request(struct request *rq)
> }
> }
>
> -void blk_mq_requeue_request(struct request *rq)
> +void blk_mq_requeue_request(struct request *rq, bool kick_requeue_list)
> {
> __blk_mq_requeue_request(rq);
>
> BUG_ON(blk_queued_rq(rq));
> - blk_mq_add_to_requeue_list(rq, true);
> + blk_mq_add_to_requeue_list(rq, true, kick_requeue_list);
> }
> EXPORT_SYMBOL(blk_mq_requeue_request);
>
> @@ -535,7 +535,8 @@ static void blk_mq_requeue_work(struct work_struct *work)
> blk_mq_start_hw_queues(q);
> }
>
> -void blk_mq_add_to_requeue_list(struct request *rq, bool at_head)
> +void blk_mq_add_to_requeue_list(struct request *rq, bool at_head,
> + bool kick_requeue_list)
> {
> struct request_queue *q = rq->q;
> unsigned long flags;
> @@ -554,6 +555,9 @@ void blk_mq_add_to_requeue_list(struct request *rq, bool at_head)
> list_add_tail(&rq->queuelist, &q->requeue_list);
> }
> spin_unlock_irqrestore(&q->requeue_lock, flags);
> +
> + if (kick_requeue_list)
> + blk_mq_kick_requeue_list(q);
> }
> EXPORT_SYMBOL(blk_mq_add_to_requeue_list);
>
> diff --git a/drivers/block/xen-blkfront.c b/drivers/block/xen-blkfront.c
> index 9908597..1ca702d 100644
> --- a/drivers/block/xen-blkfront.c
> +++ b/drivers/block/xen-blkfront.c
> @@ -2043,7 +2043,7 @@ static int blkif_recover(struct blkfront_info *info)
> /* Requeue pending requests (flush or discard) */
> list_del_init(&req->queuelist);
> BUG_ON(req->nr_phys_segments > segs);
> - blk_mq_requeue_request(req);
> + blk_mq_requeue_request(req, false);
> }
> blk_mq_kick_requeue_list(info->rq);
>
> diff --git a/drivers/md/dm-rq.c b/drivers/md/dm-rq.c
> index dc75bea..fbd37b4 100644
> --- a/drivers/md/dm-rq.c
> +++ b/drivers/md/dm-rq.c
> @@ -354,7 +354,7 @@ EXPORT_SYMBOL(dm_mq_kick_requeue_list);
>
> static void dm_mq_delay_requeue_request(struct request *rq, unsigned long msecs)
> {
> - blk_mq_requeue_request(rq);
> + blk_mq_requeue_request(rq, false);
> __dm_mq_kick_requeue_list(rq->q, msecs);
> }
>
Hmm. __dm_mq_kick_requeue_list() does essentially the same.
Have you checked if you can use 'true' here and drop the call to it?
However, it does take the queue_lock when doing so.
Is that required? None of the other drivers do it ...
Cheers,
Hannes
--
Dr. Hannes Reinecke Teamlead Storage & Networking
hare@xxxxxxx +49 911 74053 688
SUSE LINUX GmbH, Maxfeldstr. 5, 90409 Nürnberg
GF: F. Imendörffer, J. Smithard, J. Guild, D. Upmanyu, G. Norton
HRB 21284 (AG Nürnberg)
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