blk-mq: cleanup and improve list insertion

It's somewhat strange to have a list insertion function that
relies on the fact that the caller has mapped things correctly.
Pass in the hardware queue directly for insertion, which makes
for a much cleaner interface and implementation.

Reviewed-by: Keith Busch <keith.busch@intel.com>
Reviewed-by: Sagi Grimberg <sagi@grimberg.me>
Reviewed-by: Hannes Reinecke <hare@suse.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

diff --git a/block/blk-mq-sched.c b/block/blk-mq-sched.c
index 641df3f..66fda19 100644 (file)
--- a/block/blk-mq-sched.c
+++ b/block/blk-mq-sched.c
@@ -395,17 +395,11 @@ run:
                blk_mq_run_hw_queue(hctx, async);
 }
 
-void blk_mq_sched_insert_requests(struct request_queue *q,
+void blk_mq_sched_insert_requests(struct blk_mq_hw_ctx *hctx,
                                  struct blk_mq_ctx *ctx,
                                  struct list_head *list, bool run_queue_async)
 {
-       struct blk_mq_hw_ctx *hctx;
        struct elevator_queue *e;
-       struct request *rq;
-
-       /* For list inserts, requests better be on the same hw queue */
-       rq = list_first_entry(list, struct request, queuelist);
-       hctx = rq->mq_hctx;
 
        e = hctx->queue->elevator;
        if (e && e->type->ops.insert_requests)

diff --git a/block/blk-mq-sched.h b/block/blk-mq-sched.h
index 947f236..7ff5671 100644 (file)
--- a/block/blk-mq-sched.h
+++ b/block/blk-mq-sched.h
@@ -19,7 +19,7 @@ void blk_mq_sched_restart(struct blk_mq_hw_ctx *hctx);
 
 void blk_mq_sched_insert_request(struct request *rq, bool at_head,
                                 bool run_queue, bool async);
-void blk_mq_sched_insert_requests(struct request_queue *q,
+void blk_mq_sched_insert_requests(struct blk_mq_hw_ctx *hctx,
                                  struct blk_mq_ctx *ctx,
                                  struct list_head *list, bool run_queue_async);
 

diff --git a/block/blk-mq.c b/block/blk-mq.c
index 6b2859d..271726d 100644 (file)
--- a/block/blk-mq.c
+++ b/block/blk-mq.c
@@ -1624,11 +1624,12 @@ static int plug_ctx_cmp(void *priv, struct list_head *a, struct list_head *b)
 
 void blk_mq_flush_plug_list(struct blk_plug *plug, bool from_schedule)
 {
+       struct blk_mq_hw_ctx *this_hctx;
        struct blk_mq_ctx *this_ctx;
        struct request_queue *this_q;
        struct request *rq;
        LIST_HEAD(list);
-       LIST_HEAD(ctx_list);
+       LIST_HEAD(rq_list);
        unsigned int depth;
 
        list_splice_init(&plug->mq_list, &list);
@@ -1636,6 +1637,7 @@ void blk_mq_flush_plug_list(struct blk_plug *plug, bool from_schedule)
        list_sort(NULL, &list, plug_ctx_cmp);
 
        this_q = NULL;
+       this_hctx = NULL;
        this_ctx = NULL;
        depth = 0;
 
@@ -1643,30 +1645,31 @@ void blk_mq_flush_plug_list(struct blk_plug *plug, bool from_schedule)
                rq = list_entry_rq(list.next);
                list_del_init(&rq->queuelist);
                BUG_ON(!rq->q);
-               if (rq->mq_ctx != this_ctx) {
-                       if (this_ctx) {
+               if (rq->mq_hctx != this_hctx || rq->mq_ctx != this_ctx) {
+                       if (this_hctx) {
                                trace_block_unplug(this_q, depth, !from_schedule);
-                               blk_mq_sched_insert_requests(this_q, this_ctx,
-                                                               &ctx_list,
+                               blk_mq_sched_insert_requests(this_hctx, this_ctx,
+                                                               &rq_list,
                                                                from_schedule);
                        }
 
-                       this_ctx = rq->mq_ctx;
                        this_q = rq->q;
+                       this_ctx = rq->mq_ctx;
+                       this_hctx = rq->mq_hctx;
                        depth = 0;
                }
 
                depth++;
-               list_add_tail(&rq->queuelist, &ctx_list);
+               list_add_tail(&rq->queuelist, &rq_list);
        }
 
        /*
-        * If 'this_ctx' is set, we know we have entries to complete
-        * on 'ctx_list'. Do those.
+        * If 'this_hctx' is set, we know we have entries to complete
+        * on 'rq_list'. Do those.
         */
-       if (this_ctx) {
+       if (this_hctx) {
                trace_block_unplug(this_q, depth, !from_schedule);
-               blk_mq_sched_insert_requests(this_q, this_ctx, &ctx_list,
+               blk_mq_sched_insert_requests(this_hctx, this_ctx, &rq_list,
                                                from_schedule);
        }
 }