blk-mq: support at_head inserations for blk_execute_rq

This is neede for proper SG_IO operation as well as various uses of
blk_execute_rq from the SCSI midlayer.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@fb.com>

diff --git a/block/blk-exec.c b/block/blk-exec.c
index bbfc072a79c2b5d0921ee84d322e4391d85c529b..c68613bb4c79b718b87dd5dc90b3a8cdd307c3fc 100644 (file)
--- a/block/blk-exec.c
+++ b/block/blk-exec.c
@@ -65,7 +65,7 @@ void blk_execute_rq_nowait(struct request_queue *q, struct gendisk *bd_disk,
         * be resued after dying flag is set
         */
        if (q->mq_ops) {
-               blk_mq_insert_request(q, rq, true);
+               blk_mq_insert_request(q, rq, at_head, true);
                return;
        }
 

diff --git a/block/blk-mq.c b/block/blk-mq.c
index 9072d0ab184f217124407b0417242db625bf8718..c9306e3403fe28c61f17e0d5983002ee3e9fbfaf 100644 (file)
--- a/block/blk-mq.c
+++ b/block/blk-mq.c
@@ -714,13 +714,16 @@ static void blk_mq_work_fn(struct work_struct *work)
 }
 
 static void __blk_mq_insert_request(struct blk_mq_hw_ctx *hctx,
-                                   struct request *rq)
+                                   struct request *rq, bool at_head)
 {
        struct blk_mq_ctx *ctx = rq->mq_ctx;
 
        trace_block_rq_insert(hctx->queue, rq);
 
-       list_add_tail(&rq->queuelist, &ctx->rq_list);
+       if (at_head)
+               list_add(&rq->queuelist, &ctx->rq_list);
+       else
+               list_add_tail(&rq->queuelist, &ctx->rq_list);
        blk_mq_hctx_mark_pending(hctx, ctx);
 
        /*
@@ -730,7 +733,7 @@ static void __blk_mq_insert_request(struct blk_mq_hw_ctx *hctx,
 }
 
 void blk_mq_insert_request(struct request_queue *q, struct request *rq,
-                          bool run_queue)
+                          bool at_head, bool run_queue)
 {
        struct blk_mq_hw_ctx *hctx;
        struct blk_mq_ctx *ctx, *current_ctx;
@@ -749,7 +752,7 @@ void blk_mq_insert_request(struct request_queue *q, struct request *rq,
                        rq->mq_ctx = ctx;
                }
                spin_lock(&ctx->lock);
-               __blk_mq_insert_request(hctx, rq);
+               __blk_mq_insert_request(hctx, rq, at_head);
                spin_unlock(&ctx->lock);
 
                blk_mq_put_ctx(current_ctx);
@@ -781,7 +784,7 @@ void blk_mq_run_request(struct request *rq, bool run_queue, bool async)
 
        /* ctx->cpu might be offline */
        spin_lock(&ctx->lock);
-       __blk_mq_insert_request(hctx, rq);
+       __blk_mq_insert_request(hctx, rq, false);
        spin_unlock(&ctx->lock);
 
        blk_mq_put_ctx(current_ctx);
@@ -819,7 +822,7 @@ static void blk_mq_insert_requests(struct request_queue *q,
                rq = list_first_entry(list, struct request, queuelist);
                list_del_init(&rq->queuelist);
                rq->mq_ctx = ctx;
-               __blk_mq_insert_request(hctx, rq);
+               __blk_mq_insert_request(hctx, rq, false);
        }
        spin_unlock(&ctx->lock);
 
@@ -971,7 +974,7 @@ static void blk_mq_make_request(struct request_queue *q, struct bio *bio)
                __blk_mq_free_request(hctx, ctx, rq);
        else {
                blk_mq_bio_to_request(rq, bio);
-               __blk_mq_insert_request(hctx, rq);
+               __blk_mq_insert_request(hctx, rq, false);
        }
 
        spin_unlock(&ctx->lock);

diff --git a/include/linux/blk-mq.h b/include/linux/blk-mq.h
index 1e8f16f65af4551a3e6a52248ac85d4b310c9bf3..b7638be58599ca0448ec1ccef76c9586b082ab5a 100644 (file)
--- a/include/linux/blk-mq.h
+++ b/include/linux/blk-mq.h
@@ -122,7 +122,8 @@ void blk_mq_init_commands(struct request_queue *, void (*init)(void *data, struc
 
 void blk_mq_flush_plug_list(struct blk_plug *plug, bool from_schedule);
 
-void blk_mq_insert_request(struct request_queue *, struct request *, bool);
+void blk_mq_insert_request(struct request_queue *, struct request *,
+               bool, bool);
 void blk_mq_run_queues(struct request_queue *q, bool async);
 void blk_mq_free_request(struct request *rq);
 bool blk_mq_can_queue(struct blk_mq_hw_ctx *);