blk-mq: pass hctx to blk_mq_dispatch_rq_list

All requests in the 'list' of blk_mq_dispatch_rq_list belong to same
hctx, so it is better to pass hctx instead of request queue, because
blk-mq's dispatch target is hctx instead of request queue.

Signed-off-by: Ming Lei <ming.lei@redhat.com>
Tested-by: Baolin Wang <baolin.wang7@gmail.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Sagi Grimberg <sagi@grimberg.me>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Cc: Sagi Grimberg <sagi@grimberg.me>
Cc: Baolin Wang <baolin.wang7@gmail.com>
Cc: Christoph Hellwig <hch@infradead.org>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

diff --git a/block/blk-mq-sched.c b/block/blk-mq-sched.c
index a31e281..632c6f8 100644 (file)
--- a/block/blk-mq-sched.c
+++ b/block/blk-mq-sched.c
@@ -96,10 +96,9 @@ static int blk_mq_do_dispatch_sched(struct blk_mq_hw_ctx *hctx)
        struct elevator_queue *e = q->elevator;
        LIST_HEAD(rq_list);
        int ret = 0;
+       struct request *rq;
 
        do {
-               struct request *rq;
-
                if (e->type->ops.has_work && !e->type->ops.has_work(hctx))
                        break;
 
@@ -131,7 +130,7 @@ static int blk_mq_do_dispatch_sched(struct blk_mq_hw_ctx *hctx)
                 * in blk_mq_dispatch_rq_list().
                 */
                list_add(&rq->queuelist, &rq_list);
-       } while (blk_mq_dispatch_rq_list(q, &rq_list, true));
+       } while (blk_mq_dispatch_rq_list(rq->mq_hctx, &rq_list, true));
 
        return ret;
 }
@@ -161,10 +160,9 @@ static int blk_mq_do_dispatch_ctx(struct blk_mq_hw_ctx *hctx)
        LIST_HEAD(rq_list);
        struct blk_mq_ctx *ctx = READ_ONCE(hctx->dispatch_from);
        int ret = 0;
+       struct request *rq;
 
        do {
-               struct request *rq;
-
                if (!list_empty_careful(&hctx->dispatch)) {
                        ret = -EAGAIN;
                        break;
@@ -200,7 +198,7 @@ static int blk_mq_do_dispatch_ctx(struct blk_mq_hw_ctx *hctx)
                /* round robin for fair dispatch */
                ctx = blk_mq_next_ctx(hctx, rq->mq_ctx);
 
-       } while (blk_mq_dispatch_rq_list(q, &rq_list, true));
+       } while (blk_mq_dispatch_rq_list(rq->mq_hctx, &rq_list, true));
 
        WRITE_ONCE(hctx->dispatch_from, ctx);
        return ret;
@@ -240,7 +238,7 @@ static int __blk_mq_sched_dispatch_requests(struct blk_mq_hw_ctx *hctx)
         */
        if (!list_empty(&rq_list)) {
                blk_mq_sched_mark_restart_hctx(hctx);
-               if (blk_mq_dispatch_rq_list(q, &rq_list, false)) {
+               if (blk_mq_dispatch_rq_list(hctx, &rq_list, false)) {
                        if (has_sched_dispatch)
                                ret = blk_mq_do_dispatch_sched(hctx);
                        else
@@ -253,7 +251,7 @@ static int __blk_mq_sched_dispatch_requests(struct blk_mq_hw_ctx *hctx)
                ret = blk_mq_do_dispatch_ctx(hctx);
        } else {
                blk_mq_flush_busy_ctxs(hctx, &rq_list);
-               blk_mq_dispatch_rq_list(q, &rq_list, false);
+               blk_mq_dispatch_rq_list(hctx, &rq_list, false);
        }
 
        return ret;

diff --git a/block/blk-mq.c b/block/blk-mq.c
index 8cdc868..492aeda 100644 (file)
--- a/block/blk-mq.c
+++ b/block/blk-mq.c
@@ -1258,10 +1258,10 @@ static void blk_mq_handle_zone_resource(struct request *rq,
 /*
  * Returns true if we did some work AND can potentially do more.
  */
-bool blk_mq_dispatch_rq_list(struct request_queue *q, struct list_head *list,
+bool blk_mq_dispatch_rq_list(struct blk_mq_hw_ctx *hctx, struct list_head *list,
                             bool got_budget)
 {
-       struct blk_mq_hw_ctx *hctx;
+       struct request_queue *q = hctx->queue;
        struct request *rq, *nxt;
        bool no_tag = false;
        int errors, queued;
@@ -1283,7 +1283,7 @@ bool blk_mq_dispatch_rq_list(struct request_queue *q, struct list_head *list,
 
                rq = list_first_entry(list, struct request, queuelist);
 
-               hctx = rq->mq_hctx;
+               WARN_ON_ONCE(hctx != rq->mq_hctx);
                if (!got_budget && !blk_mq_get_dispatch_budget(q)) {
                        blk_mq_put_driver_tag(rq);
                        no_budget_avail = true;

diff --git a/block/blk-mq.h b/block/blk-mq.h
index e4af193..3fd1ed7 100644 (file)
--- a/block/blk-mq.h
+++ b/block/blk-mq.h
@@ -40,7 +40,7 @@ struct blk_mq_ctx {
 void blk_mq_exit_queue(struct request_queue *q);
 int blk_mq_update_nr_requests(struct request_queue *q, unsigned int nr);
 void blk_mq_wake_waiters(struct request_queue *q);
-bool blk_mq_dispatch_rq_list(struct request_queue *, struct list_head *, bool);
+bool blk_mq_dispatch_rq_list(struct blk_mq_hw_ctx *hctx, struct list_head *, bool);
 void blk_mq_add_to_requeue_list(struct request *rq, bool at_head,
                                bool kick_requeue_list);
 void blk_mq_flush_busy_ctxs(struct blk_mq_hw_ctx *hctx, struct list_head *list);