block: factor out blk_mq_dispatch_queue_requests() helper

Factor out the logic from blk_mq_flush_plug_list() that calls
->queue_rqs() with a fallback to ->queue_rq() into a helper function
blk_mq_dispatch_queue_requests(). This is in preparation for using this
code with other lists of requests.

Signed-off-by: Caleb Sander Mateos <csander@purestorage.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Link: https://lore.kernel.org/r/20250426011728.4189119-3-csander@purestorage.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>

diff --git a/block/blk-mq.c b/block/blk-mq.c
index fb514fd41d761151610bc0eafa6ad2cb1134ab28..a777cb361ee3024975f9d53a498825277b35e909 100644 (file)
--- a/block/blk-mq.c
+++ b/block/blk-mq.c
@@ -2836,6 +2836,27 @@ static void __blk_mq_flush_list(struct request_queue *q, struct rq_list *rqs)
        q->mq_ops->queue_rqs(rqs);
 }
 
+static void blk_mq_dispatch_queue_requests(struct rq_list *rqs, unsigned depth)
+{
+       struct request_queue *q = rq_list_peek(rqs)->q;
+
+       trace_block_unplug(q, depth, true);
+
+       /*
+        * Peek first request and see if we have a ->queue_rqs() hook.
+        * If we do, we can dispatch the whole list in one go.
+        * We already know at this point that all requests belong to the
+        * same queue, caller must ensure that's the case.
+        */
+       if (q->mq_ops->queue_rqs) {
+               blk_mq_run_dispatch_ops(q, __blk_mq_flush_list(q, rqs));
+               if (rq_list_empty(rqs))
+                       return;
+       }
+
+       blk_mq_run_dispatch_ops(q, blk_mq_issue_direct(rqs));
+}
+
 static void blk_mq_dispatch_list(struct rq_list *rqs, bool from_sched)
 {
        struct blk_mq_hw_ctx *this_hctx = NULL;
@@ -2883,7 +2904,6 @@ static void blk_mq_dispatch_list(struct rq_list *rqs, bool from_sched)
 
 void blk_mq_flush_plug_list(struct blk_plug *plug, bool from_schedule)
 {
-       struct request *rq;
        unsigned int depth;
 
        /*
@@ -2899,26 +2919,7 @@ void blk_mq_flush_plug_list(struct blk_plug *plug, bool from_schedule)
        plug->rq_count = 0;
 
        if (!plug->multiple_queues && !plug->has_elevator && !from_schedule) {
-               struct request_queue *q;
-
-               rq = rq_list_peek(&plug->mq_list);
-               q = rq->q;
-               trace_block_unplug(q, depth, true);
-
-               /*
-                * Peek first request and see if we have a ->queue_rqs() hook.
-                * If we do, we can dispatch the whole plug list in one go. We
-                * already know at this point that all requests belong to the
-                * same queue, caller must ensure that's the case.
-                */
-               if (q->mq_ops->queue_rqs) {
-                       blk_mq_run_dispatch_ops(q,
-                               __blk_mq_flush_list(q, &plug->mq_list));
-                       if (rq_list_empty(&plug->mq_list))
-                               return;
-               }
-
-               blk_mq_run_dispatch_ops(q, blk_mq_issue_direct(&plug->mq_list));
+               blk_mq_dispatch_queue_requests(&plug->mq_list, depth);
                if (rq_list_empty(&plug->mq_list))
                        return;
        }