@@ -1946,6 +1946,33 @@ static void scsi_mq_done(struct scsi_cmnd *cmd)
blk_mq_complete_request(cmd->request);
}
+static void scsi_mq_put_budget(struct blk_mq_hw_ctx *hctx)
+{
+ struct request_queue *q = hctx->queue;
+ struct scsi_device *sdev = q->queuedata;
+
+ atomic_dec(&sdev->device_busy);
+ put_device(&sdev->sdev_gendev);
+}
+
+static bool scsi_mq_get_budget(struct blk_mq_hw_ctx *hctx)
+{
+ struct request_queue *q = hctx->queue;
+ struct scsi_device *sdev = q->queuedata;
+
+ if (!get_device(&sdev->sdev_gendev))
+ goto out;
+ if (!scsi_dev_queue_ready(q, sdev))
+ goto out_put_device;
+
+ return true;
+
+out_put_device:
+ put_device(&sdev->sdev_gendev);
+out:
+ return false;
+}
+
static blk_status_t scsi_queue_rq(struct blk_mq_hw_ctx *hctx,
const struct blk_mq_queue_data *bd)
{
@@ -1962,13 +1989,8 @@ static blk_status_t scsi_queue_rq(struct blk_mq_hw_ctx *hctx,
goto out;
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))
- goto out_dec_device_busy;
+ goto out_put_budget;
if (!scsi_host_queue_ready(q, shost, sdev))
goto out_dec_target_busy;
@@ -2003,10 +2025,8 @@ static blk_status_t scsi_queue_rq(struct blk_mq_hw_ctx *hctx,
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_put_budget:
+ scsi_mq_put_budget(hctx);
out:
switch (ret) {
case BLK_STS_OK:
@@ -2211,6 +2231,8 @@ 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,
We need to tell blk-mq to reserve resource before queuing one request, so implement these two callbacks. Then blk-mq can avoid to dequeue request earlier, and IO merge can be improved a lot. Signed-off-by: Ming Lei <ming.lei@redhat.com> --- drivers/scsi/scsi_lib.c | 42 ++++++++++++++++++++++++++++++++---------- 1 file changed, 32 insertions(+), 10 deletions(-)