blk-mq: save default hctx into ctx->hctxs for not-supported type

Currently, we check whether the hctx type is supported every time
in hot path. Actually, this is not necessary, we could save the
default hctx into ctx->hctxs if the type is not supported when
map swqueues and use it directly with ctx->hctxs[type].

We also needn't check whether the poll is enabled or not, because
the caller would clear the REQ_HIPRI in that case.

Signed-off-by: Jianchao Wang <jianchao.w.wang@oracle.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

1 files changed, 8 insertions, 1 deletions

diff --git a/block/blk-mq.c b/block/blk-mq.c
index 445d0a2642ae..8a825aebc6b5 100644
--- a/block/blk-mq.c
+++ b/block/blk-mq.c
@@ -2431,8 +2431,11 @@ static void blk_mq_map_swqueue(struct request_queue *q)
 
 		ctx = per_cpu_ptr(q->queue_ctx, i);
 		for (j = 0; j < set->nr_maps; j++) {
-			if (!set->map[j].nr_queues)
+			if (!set->map[j].nr_queues) {
+				ctx->hctxs[j] = blk_mq_map_queue_type(q,
+						HCTX_TYPE_DEFAULT, i);
 				continue;
+			}
 
 			hctx = blk_mq_map_queue_type(q, j, i);
 			ctx->hctxs[j] = hctx;
@@ -2455,6 +2458,10 @@ static void blk_mq_map_swqueue(struct request_queue *q)
 			 */
 			BUG_ON(!hctx->nr_ctx);
 		}
+
+		for (; j < HCTX_MAX_TYPES; j++)
+			ctx->hctxs[j] = blk_mq_map_queue_type(q,
+					HCTX_TYPE_DEFAULT, i);
 	}
 
 	mutex_unlock(&q->sysfs_lock);