1 files changed, 30 insertions, 23 deletions

diff --git a/block/blk-mq-sched.c b/block/blk-mq-sched.c
index 109611445d40..55a0fd105147 100644
--- a/block/blk-mq-sched.c
+++ b/block/blk-mq-sched.c
@@ -59,19 +59,17 @@ static bool blk_mq_dispatch_hctx_list(struct list_head *rq_list)
 		list_first_entry(rq_list, struct request, queuelist)->mq_hctx;
 	struct request *rq;
 	LIST_HEAD(hctx_list);
-	unsigned int count = 0;
 
 	list_for_each_entry(rq, rq_list, queuelist) {
 		if (rq->mq_hctx != hctx) {
 			list_cut_before(&hctx_list, rq_list, &rq->queuelist);
 			goto dispatch;
 		}
-		count++;
 	}
 	list_splice_tail_init(rq_list, &hctx_list);
 
 dispatch:
-	return blk_mq_dispatch_rq_list(hctx, &hctx_list, count);
+	return blk_mq_dispatch_rq_list(hctx, &hctx_list, false);
 }
 
 #define BLK_MQ_BUDGET_DELAY	3		/* ms units */
@@ -167,7 +165,7 @@ static int __blk_mq_do_dispatch_sched(struct blk_mq_hw_ctx *hctx)
 			dispatched |= blk_mq_dispatch_hctx_list(&rq_list);
 		} while (!list_empty(&rq_list));
 	} else {
-		dispatched = blk_mq_dispatch_rq_list(hctx, &rq_list, count);
+		dispatched = blk_mq_dispatch_rq_list(hctx, &rq_list, false);
 	}
 
 	if (busy)
@@ -261,7 +259,7 @@ static int blk_mq_do_dispatch_ctx(struct blk_mq_hw_ctx *hctx)
 		/* round robin for fair dispatch */
 		ctx = blk_mq_next_ctx(hctx, rq->mq_ctx);
 
-	} while (blk_mq_dispatch_rq_list(rq->mq_hctx, &rq_list, 1));
+	} while (blk_mq_dispatch_rq_list(rq->mq_hctx, &rq_list, false));
 
 	WRITE_ONCE(hctx->dispatch_from, ctx);
 	return ret;
@@ -298,7 +296,7 @@ static int __blk_mq_sched_dispatch_requests(struct blk_mq_hw_ctx *hctx)
 	 */
 	if (!list_empty(&rq_list)) {
 		blk_mq_sched_mark_restart_hctx(hctx);
-		if (!blk_mq_dispatch_rq_list(hctx, &rq_list, 0))
+		if (!blk_mq_dispatch_rq_list(hctx, &rq_list, true))
 			return 0;
 		need_dispatch = true;
 	} else {
@@ -312,7 +310,7 @@ static int __blk_mq_sched_dispatch_requests(struct blk_mq_hw_ctx *hctx)
 	if (need_dispatch)
 		return blk_mq_do_dispatch_ctx(hctx);
 	blk_mq_flush_busy_ctxs(hctx, &rq_list);
-	blk_mq_dispatch_rq_list(hctx, &rq_list, 0);
+	blk_mq_dispatch_rq_list(hctx, &rq_list, true);
 	return 0;
 }
 
@@ -436,6 +434,30 @@ static int blk_mq_init_sched_shared_tags(struct request_queue *queue)
 	return 0;
 }
 
+void blk_mq_sched_reg_debugfs(struct request_queue *q)
+{
+	struct blk_mq_hw_ctx *hctx;
+	unsigned long i;
+
+	mutex_lock(&q->debugfs_mutex);
+	blk_mq_debugfs_register_sched(q);
+	queue_for_each_hw_ctx(q, hctx, i)
+		blk_mq_debugfs_register_sched_hctx(q, hctx);
+	mutex_unlock(&q->debugfs_mutex);
+}
+
+void blk_mq_sched_unreg_debugfs(struct request_queue *q)
+{
+	struct blk_mq_hw_ctx *hctx;
+	unsigned long i;
+
+	mutex_lock(&q->debugfs_mutex);
+	queue_for_each_hw_ctx(q, hctx, i)
+		blk_mq_debugfs_unregister_sched_hctx(hctx);
+	blk_mq_debugfs_unregister_sched(q);
+	mutex_unlock(&q->debugfs_mutex);
+}
+
 /* caller must have a reference to @e, will grab another one if successful */
 int blk_mq_init_sched(struct request_queue *q, struct elevator_type *e)
 {
@@ -469,10 +491,6 @@ int blk_mq_init_sched(struct request_queue *q, struct elevator_type *e)
 	if (ret)
 		goto err_free_map_and_rqs;
 
-	mutex_lock(&q->debugfs_mutex);
-	blk_mq_debugfs_register_sched(q);
-	mutex_unlock(&q->debugfs_mutex);
-
 	queue_for_each_hw_ctx(q, hctx, i) {
 		if (e->ops.init_hctx) {
 			ret = e->ops.init_hctx(hctx, i);
@@ -484,11 +502,7 @@ int blk_mq_init_sched(struct request_queue *q, struct elevator_type *e)
 				return ret;
 			}
 		}
-		mutex_lock(&q->debugfs_mutex);
-		blk_mq_debugfs_register_sched_hctx(q, hctx);
-		mutex_unlock(&q->debugfs_mutex);
 	}
-
 	return 0;
 
 err_free_map_and_rqs:
@@ -527,10 +541,6 @@ void blk_mq_exit_sched(struct request_queue *q, struct elevator_queue *e)
 	unsigned int flags = 0;
 
 	queue_for_each_hw_ctx(q, hctx, i) {
-		mutex_lock(&q->debugfs_mutex);
-		blk_mq_debugfs_unregister_sched_hctx(hctx);
-		mutex_unlock(&q->debugfs_mutex);
-
 		if (e->type->ops.exit_hctx && hctx->sched_data) {
 			e->type->ops.exit_hctx(hctx, i);
 			hctx->sched_data = NULL;
@@ -538,12 +548,9 @@ void blk_mq_exit_sched(struct request_queue *q, struct elevator_queue *e)
 		flags = hctx->flags;
 	}
 
-	mutex_lock(&q->debugfs_mutex);
-	blk_mq_debugfs_unregister_sched(q);
-	mutex_unlock(&q->debugfs_mutex);
-
 	if (e->type->ops.exit_sched)
 		e->type->ops.exit_sched(e);
 	blk_mq_sched_tags_teardown(q, flags);
+	set_bit(ELEVATOR_FLAG_DYING, &q->elevator->flags);
 	q->elevator = NULL;
 }