[PATCH 1/9] blk-mq: pass request queue into get/put budget callback

[Ming Lei <ming.lei@redhat.com>]

blk-mq budget is abstract from scsi's device queue depth, and it is
always per-request-queue instead of hctx.

It can be quite absurd to get a budget from one hctx, then dequeue a
request from scheduler queue, and this request may not belong to this
hctx, at least for bfq and deadline.

So fix the mess and always pass request queue to get/put budget
callback.

Cc: Sagi Grimberg <sagi@grimberg.me>
Cc: Baolin Wang <baolin.wang7@gmail.com>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: Douglas Anderson <dianders@chromium.org>
Signed-off-by: Ming Lei <ming.lei@redhat.com>
---
 block/blk-mq-sched.c    |  8 ++++----
 block/blk-mq.c          |  8 ++++----
 block/blk-mq.h          | 12 ++++--------
 drivers/scsi/scsi_lib.c |  8 +++-----
 include/linux/blk-mq.h  |  4 ++--
 5 files changed, 17 insertions(+), 23 deletions(-)

diff --git a/block/blk-mq-sched.c b/block/blk-mq-sched.c
index fdcc2c1dd178..a31e281e9d31 100644
--- a/block/blk-mq-sched.c
+++ b/block/blk-mq-sched.c
@@ -108,12 +108,12 @@ static int blk_mq_do_dispatch_sched(struct blk_mq_hw_ctx *hctx)
 			break;
 		}
 
-		if (!blk_mq_get_dispatch_budget(hctx))
+		if (!blk_mq_get_dispatch_budget(q))
 			break;
 
 		rq = e->type->ops.dispatch_request(hctx);
 		if (!rq) {
-			blk_mq_put_dispatch_budget(hctx);
+			blk_mq_put_dispatch_budget(q);
 			/*
 			 * We're releasing without dispatching. Holding the
 			 * budget could have blocked any "hctx"s with the
@@ -173,12 +173,12 @@ static int blk_mq_do_dispatch_ctx(struct blk_mq_hw_ctx *hctx)
 		if (!sbitmap_any_bit_set(&hctx->ctx_map))
 			break;
 
-		if (!blk_mq_get_dispatch_budget(hctx))
+		if (!blk_mq_get_dispatch_budget(q))
 			break;
 
 		rq = blk_mq_dequeue_from_ctx(hctx, ctx);
 		if (!rq) {
-			blk_mq_put_dispatch_budget(hctx);
+			blk_mq_put_dispatch_budget(q);
 			/*
 			 * We're releasing without dispatching. Holding the
 			 * budget could have blocked any "hctx"s with the
diff --git a/block/blk-mq.c b/block/blk-mq.c
index 9ee695bdf873..74ecaffd2d64 100644
--- a/block/blk-mq.c
+++ b/block/blk-mq.c
@@ -1225,7 +1225,7 @@ bool blk_mq_dispatch_rq_list(struct request_queue *q, struct list_head *list,
 		rq = list_first_entry(list, struct request, queuelist);
 
 		hctx = rq->mq_hctx;
-		if (!got_budget && !blk_mq_get_dispatch_budget(hctx)) {
+		if (!got_budget && !blk_mq_get_dispatch_budget(q)) {
 			blk_mq_put_driver_tag(rq);
 			no_budget_avail = true;
 			break;
@@ -1240,7 +1240,7 @@ bool blk_mq_dispatch_rq_list(struct request_queue *q, struct list_head *list,
 			 * we'll re-run it below.
 			 */
 			if (!blk_mq_mark_tag_wait(hctx, rq)) {
-				blk_mq_put_dispatch_budget(hctx);
+				blk_mq_put_dispatch_budget(q);
 				/*
 				 * For non-shared tags, the RESTART check
 				 * will suffice.
@@ -1887,11 +1887,11 @@ static blk_status_t __blk_mq_try_issue_directly(struct blk_mq_hw_ctx *hctx,
 	if (q->elevator && !bypass_insert)
 		goto insert;
 
-	if (!blk_mq_get_dispatch_budget(hctx))
+	if (!blk_mq_get_dispatch_budget(q))
 		goto insert;
 
 	if (!blk_mq_get_driver_tag(rq)) {
-		blk_mq_put_dispatch_budget(hctx);
+		blk_mq_put_dispatch_budget(q);
 		goto insert;
 	}
 
diff --git a/block/blk-mq.h b/block/blk-mq.h
index 10bfdfb494fa..9540770de9dc 100644
--- a/block/blk-mq.h
+++ b/block/blk-mq.h
@@ -180,20 +180,16 @@ unsigned int blk_mq_in_flight(struct request_queue *q, struct hd_struct *part);
 void blk_mq_in_flight_rw(struct request_queue *q, struct hd_struct *part,
 			 unsigned int inflight[2]);
 
-static inline void blk_mq_put_dispatch_budget(struct blk_mq_hw_ctx *hctx)
+static inline void blk_mq_put_dispatch_budget(struct request_queue *q)
 {
-	struct request_queue *q = hctx->queue;
-
 	if (q->mq_ops->put_budget)
-		q->mq_ops->put_budget(hctx);
+		q->mq_ops->put_budget(q);
 }
 
-static inline bool blk_mq_get_dispatch_budget(struct blk_mq_hw_ctx *hctx)
+static inline bool blk_mq_get_dispatch_budget(struct request_queue *q)
 {
-	struct request_queue *q = hctx->queue;
-
 	if (q->mq_ops->get_budget)
-		return q->mq_ops->get_budget(hctx);
+		return q->mq_ops->get_budget(q);
 	return true;
 }
 
diff --git a/drivers/scsi/scsi_lib.c b/drivers/scsi/scsi_lib.c
index 82ad0244b3d0..b9adee0a9266 100644
--- a/drivers/scsi/scsi_lib.c
+++ b/drivers/scsi/scsi_lib.c
@@ -1624,17 +1624,15 @@ static void scsi_mq_done(struct scsi_cmnd *cmd)
 		clear_bit(SCMD_STATE_COMPLETE, &cmd->state);
 }
 
-static void scsi_mq_put_budget(struct blk_mq_hw_ctx *hctx)
+static void scsi_mq_put_budget(struct request_queue *q)
 {
-	struct request_queue *q = hctx->queue;
 	struct scsi_device *sdev = q->queuedata;
 
 	atomic_dec(&sdev->device_busy);
 }
 
-static bool scsi_mq_get_budget(struct blk_mq_hw_ctx *hctx)
+static bool scsi_mq_get_budget(struct request_queue *q)
 {
-	struct request_queue *q = hctx->queue;
 	struct scsi_device *sdev = q->queuedata;
 
 	return scsi_dev_queue_ready(q, sdev);
@@ -1701,7 +1699,7 @@ static blk_status_t scsi_queue_rq(struct blk_mq_hw_ctx *hctx,
 	if (scsi_target(sdev)->can_queue > 0)
 		atomic_dec(&scsi_target(sdev)->target_busy);
 out_put_budget:
-	scsi_mq_put_budget(hctx);
+	scsi_mq_put_budget(q);
 	switch (ret) {
 	case BLK_STS_OK:
 		break;
diff --git a/include/linux/blk-mq.h b/include/linux/blk-mq.h
index d7307795439a..43e38d21ca4a 100644
--- a/include/linux/blk-mq.h
+++ b/include/linux/blk-mq.h
@@ -268,8 +268,8 @@ struct blk_mq_queue_data {
 typedef blk_status_t (queue_rq_fn)(struct blk_mq_hw_ctx *,
 		const struct blk_mq_queue_data *);
 typedef void (commit_rqs_fn)(struct blk_mq_hw_ctx *);
-typedef bool (get_budget_fn)(struct blk_mq_hw_ctx *);
-typedef void (put_budget_fn)(struct blk_mq_hw_ctx *);
+typedef bool (get_budget_fn)(struct request_queue *);
+typedef void (put_budget_fn)(struct request_queue *);
 typedef enum blk_eh_timer_return (timeout_fn)(struct request *, bool);
 typedef int (init_hctx_fn)(struct blk_mq_hw_ctx *, void *, unsigned int);
 typedef void (exit_hctx_fn)(struct blk_mq_hw_ctx *, unsigned int);
-- 
2.25.2