From 0df21c86bdbfd17dec9ab898312af9bfb74d5d86 Mon Sep 17 00:00:00 2001 From: Ming Lei Date: Sat, 14 Oct 2017 17:22:32 +0800 Subject: [PATCH] scsi: implement .get_budget and .put_budget for blk-mq We need to tell blk-mq to reserve resources before queuing one request, so implement these two callbacks. Then blk-mq can avoid to dequeue request too early, and IO merging can be improved a lot. Signed-off-by: Ming Lei Signed-off-by: Jens Axboe --- drivers/scsi/scsi_lib.c | 75 ++++++++++++++++++++++++++++------------- 1 file changed, 52 insertions(+), 23 deletions(-) diff --git a/drivers/scsi/scsi_lib.c b/drivers/scsi/scsi_lib.c index d159bb085714..6f10afaca25b 100644 --- a/drivers/scsi/scsi_lib.c +++ b/drivers/scsi/scsi_lib.c @@ -1946,25 +1946,32 @@ static void scsi_mq_done(struct scsi_cmnd *cmd) blk_mq_complete_request(cmd->request); } -static blk_status_t scsi_queue_rq(struct blk_mq_hw_ctx *hctx, - const struct blk_mq_queue_data *bd) +static void scsi_mq_put_budget(struct blk_mq_hw_ctx *hctx) { - struct request *req = bd->rq; - struct request_queue *q = req->q; + struct request_queue *q = hctx->queue; + struct scsi_device *sdev = q->queuedata; + struct Scsi_Host *shost = sdev->host; + + atomic_dec(&shost->host_busy); + if (scsi_target(sdev)->can_queue > 0) + atomic_dec(&scsi_target(sdev)->target_busy); + atomic_dec(&sdev->device_busy); + put_device(&sdev->sdev_gendev); +} + +static blk_status_t scsi_mq_get_budget(struct blk_mq_hw_ctx *hctx) +{ + struct request_queue *q = hctx->queue; struct scsi_device *sdev = q->queuedata; struct Scsi_Host *shost = sdev->host; - struct scsi_cmnd *cmd = blk_mq_rq_to_pdu(req); blk_status_t ret; - int reason; - ret = prep_to_mq(scsi_prep_state_check(sdev, req)); - if (ret != BLK_STS_OK) - goto out; + ret = prep_to_mq(scsi_prep_state_check(sdev, NULL)); + if (ret == BLK_STS_RESOURCE || ret != BLK_STS_OK) + return ret; - ret = BLK_STS_RESOURCE; if (!get_device(&sdev->sdev_gendev)) goto out; - if (!scsi_dev_queue_ready(q, sdev)) goto out_put_device; if (!scsi_target_queue_ready(shost, sdev)) @@ -1972,10 +1979,38 @@ static blk_status_t scsi_queue_rq(struct blk_mq_hw_ctx *hctx, if (!scsi_host_queue_ready(q, shost, sdev)) goto out_dec_target_busy; + return BLK_STS_OK; + +out_dec_target_busy: + if (scsi_target(sdev)->can_queue > 0) + atomic_dec(&scsi_target(sdev)->target_busy); +out_dec_device_busy: + atomic_dec(&sdev->device_busy); +out_put_device: + put_device(&sdev->sdev_gendev); +out: + return BLK_STS_RESOURCE; +} + +static blk_status_t scsi_queue_rq(struct blk_mq_hw_ctx *hctx, + const struct blk_mq_queue_data *bd) +{ + struct request *req = bd->rq; + struct request_queue *q = req->q; + struct scsi_device *sdev = q->queuedata; + struct scsi_cmnd *cmd = blk_mq_rq_to_pdu(req); + blk_status_t ret; + int reason; + + ret = prep_to_mq(scsi_prep_state_check(sdev, req)); + if (ret != BLK_STS_OK) + goto out_put_budget; + + ret = BLK_STS_RESOURCE; if (!(req->rq_flags & RQF_DONTPREP)) { ret = prep_to_mq(scsi_mq_prep_fn(req)); if (ret != BLK_STS_OK) - goto out_dec_host_busy; + goto out_put_budget; req->rq_flags |= RQF_DONTPREP; } else { blk_mq_start_request(req); @@ -1993,21 +2028,13 @@ static blk_status_t scsi_queue_rq(struct blk_mq_hw_ctx *hctx, if (reason) { scsi_set_blocked(cmd, reason); ret = BLK_STS_RESOURCE; - goto out_dec_host_busy; + goto out_put_budget; } return BLK_STS_OK; -out_dec_host_busy: - atomic_dec(&shost->host_busy); -out_dec_target_busy: - if (scsi_target(sdev)->can_queue > 0) - atomic_dec(&scsi_target(sdev)->target_busy); -out_dec_device_busy: - atomic_dec(&sdev->device_busy); -out_put_device: - put_device(&sdev->sdev_gendev); -out: +out_put_budget: + scsi_mq_put_budget(hctx); switch (ret) { case BLK_STS_OK: break; @@ -2211,6 +2238,8 @@ struct request_queue *scsi_old_alloc_queue(struct scsi_device *sdev) } static const struct blk_mq_ops scsi_mq_ops = { + .get_budget = scsi_mq_get_budget, + .put_budget = scsi_mq_put_budget, .queue_rq = scsi_queue_rq, .complete = scsi_softirq_done, .timeout = scsi_timeout, -- 2.20.1