blk-mq: add blk_mq_free_hctx_request()

It's silly to use blk_mq_free_request() which in turn maps the
request to the hardware queue, for places where we already know
what the hardware queue is. This saves us an extra mapping of a
hardware queue on request completion, if the caller knows this
information already.

Signed-off-by: Jens Axboe <axboe@fb.com>

diff --git a/block/blk-mq.c b/block/blk-mq.c
index fdf12152946e2cf167e4bbf8ef19028d0fadaa1d..4347aa2be6ae5610dee9b04a8ec5f64db40fe2d4 100644 (file)
--- a/block/blk-mq.c
+++ b/block/blk-mq.c
@@ -269,16 +269,23 @@ static void __blk_mq_free_request(struct blk_mq_hw_ctx *hctx,
        blk_mq_queue_exit(q);
 }
 
-void blk_mq_free_request(struct request *rq)
+void blk_mq_free_hctx_request(struct blk_mq_hw_ctx *hctx, struct request *rq)
 {
        struct blk_mq_ctx *ctx = rq->mq_ctx;
-       struct blk_mq_hw_ctx *hctx;
-       struct request_queue *q = rq->q;
 
        ctx->rq_completed[rq_is_sync(rq)]++;
-
-       hctx = q->mq_ops->map_queue(q, ctx->cpu);
        __blk_mq_free_request(hctx, ctx, rq);
+
+}
+EXPORT_SYMBOL_GPL(blk_mq_free_hctx_request);
+
+void blk_mq_free_request(struct request *rq)
+{
+       struct blk_mq_hw_ctx *hctx;
+       struct request_queue *q = rq->q;
+
+       hctx = q->mq_ops->map_queue(q, rq->mq_ctx->cpu);
+       blk_mq_free_hctx_request(hctx, rq);
 }
 EXPORT_SYMBOL_GPL(blk_mq_free_request);
 

diff --git a/include/linux/blk-mq.h b/include/linux/blk-mq.h
index c3b64ec5321e740f38d947c7538219f0b942bbf1..fb0a4fb3dc2b10c49567ce1fd3a109b34ad177f3 100644 (file)
--- a/include/linux/blk-mq.h
+++ b/include/linux/blk-mq.h
@@ -169,6 +169,7 @@ void blk_mq_flush_plug_list(struct blk_plug *plug, bool from_schedule);
 void blk_mq_insert_request(struct request *, bool, bool, bool);
 void blk_mq_run_queues(struct request_queue *q, bool async);
 void blk_mq_free_request(struct request *rq);
+void blk_mq_free_hctx_request(struct blk_mq_hw_ctx *, struct request *rq);
 bool blk_mq_can_queue(struct blk_mq_hw_ctx *);
 struct request *blk_mq_alloc_request(struct request_queue *q, int rw,
                gfp_t gfp, bool reserved);