diff mbox

[v4,2/4] blk-mq: introduce blk_mq_get_queue_depth()

Message ID 20170512103103.24485-3-ming.lei@redhat.com (mailing list archive)
State New, archived
Headers show

Commit Message

Ming Lei May 12, 2017, 10:31 a.m. UTC 
The hardware queue depth can be resized via blk_mq_update_nr_requests(),
so introduce this helper for retrieving queue's depth easily.

Reviewed-by: Omar Sandoval <osandov@fb.com>
Signed-off-by: Ming Lei <ming.lei@redhat.com>
---
 block/blk-mq.c | 15 +++++++++++++++
 block/blk-mq.h |  1 +
 2 files changed, 16 insertions(+)
diff mbox

Patch

diff --git a/block/blk-mq.c b/block/blk-mq.c
index fb2607bc3f05..389d53a6c1d6 100644
--- a/block/blk-mq.c
+++ b/block/blk-mq.c
@@ -2139,6 +2139,21 @@  static void blk_mq_map_swqueue(struct request_queue *q,
 	}
 }
 
+/*
+ * Queue depth can be changed via blk_mq_update_nr_requests(),
+ * so use this helper to retrieve queue's depth.
+ */
+int blk_mq_get_queue_depth(struct request_queue *q)
+{
+	/*
+	 * All queues have same queue depth, need to revisit
+	 * if per hw-queue depth is supported.
+	 */
+	struct blk_mq_tags	*tags = q->tag_set->tags[0];
+
+	return tags->bitmap_tags.sb.depth + tags->breserved_tags.sb.depth;
+}
+
 static void queue_set_hctx_shared(struct request_queue *q, bool shared)
 {
 	struct blk_mq_hw_ctx *hctx;
diff --git a/block/blk-mq.h b/block/blk-mq.h
index cc67b48e3551..d49d46de2923 100644
--- a/block/blk-mq.h
+++ b/block/blk-mq.h
@@ -138,6 +138,7 @@  void __blk_mq_finish_request(struct blk_mq_hw_ctx *hctx, struct blk_mq_ctx *ctx,
 void blk_mq_finish_request(struct request *rq);
 struct request *__blk_mq_alloc_request(struct blk_mq_alloc_data *data,
 					unsigned int op);
+int blk_mq_get_queue_depth(struct request_queue *q);
 
 static inline bool blk_mq_hctx_stopped(struct blk_mq_hw_ctx *hctx)
 {