tags(set, nr_hw_queues);
+			et = blk_mq_alloc_sched_tags(set, nr_hw_queues,
+					blk_mq_default_nr_requests(set));
 			if (!et)
 				goto out_unwind;
 			if (xa_insert(et_table, q->id, et, gfp))
diff --git a/block/blk-mq-sched.h b/block/blk-mq-sched.h
index fe83187f41db4..8e21a6b1415d9 100644
--- a/block/blk-mq-sched.h
+++ b/block/blk-mq-sched.h
@@ -24,7 +24,7 @@ void blk_mq_exit_sched(struct request_queue *q, struct elevator_queue *e);
 void blk_mq_sched_free_rqs(struct request_queue *q);
 
 struct elevator_tags *blk_mq_alloc_sched_tags(struct blk_mq_tag_set *set,
-		unsigned int nr_hw_queues);
+		unsigned int nr_hw_queues, unsigned int nr_requests);
 int blk_mq_alloc_sched_tags_batch(struct xarray *et_table,
 		struct blk_mq_tag_set *set, unsigned int nr_hw_queues);
 void blk_mq_free_sched_tags(struct elevator_tags *et,
diff --git a/block/blk-mq.h b/block/blk-mq.h
index 2b3ade60c90b2..731f4578d9a84 100644
--- a/block/blk-mq.h
+++ b/block/blk-mq.h
@@ -109,6 +109,17 @@ static inline struct blk_mq_hw_ctx *blk_mq_map_queue(blk_opf_t opf,
 	return ctx->hctxs[blk_mq_get_hctx_type(opf)];
 }
 
+/*
+ * Default to double of smaller one between hw queue_depth and
+ * 128, since we don't split into sync/async like the old code
+ * did. Additionally, this is a per-hw queue depth.
+ */
+static inline unsigned int blk_mq_default_nr_requests(
+		struct blk_mq_tag_set *set)
+{
+	return 2 * min_t(unsigned int, set->queue_depth, BLKDEV_DEFAULT_RQ);
+}
+
 /*
  * sysfs helpers
  */
diff --git a/block/elevator.c b/block/elevator.c
index fe96c6f4753ca..e2ebfbf107b3a 100644
--- a/block/elevator.c
+++ b/block/elevator.c
@@ -669,7 +669,8 @@ static int elevator_change(struct request_queue *q, struct elv_change_ctx *ctx)
 	lockdep_assert_held(&set->update_nr_hwq_lock);
 
 	if (strncmp(ctx->name, "none", 4)) {
-		ctx->et = blk_mq_alloc_sched_tags(set, set->nr_hw_queues);
+		ctx->et = blk_mq_alloc_sched_tags(set, set->nr_hw_queues,
+				blk_mq_default_nr_requests(set));
 		if (!ctx->et)
 			return -ENOMEM;
 	}
-- 
2.51.0[PATCH 6.17 130/563] blk-mq-sched: add new parameter nr_requests in blk_mq_alloc_sched_tags()Greg Kroah-Hartman <gregkh@linuxfoundation.org> undefinedstable@vger.kernel.org undefined undefined undefined undefined undefined undefined˜cƒ™