[PATCH 1/3] block: take rq_list instead of plug in dispatch functions

[Caleb Sander Mateos <csander@purestorage.com>]

blk_mq_plug_issue_direct(), __blk_mq_flush_plug_list(), and
blk_mq_dispatch_plug_list() take a struct blk_plug * but only use its
mq_list. Pass the struct rq_list * instead in preparation for calling
them with other lists of requests.

Drop "plug" from the function names as they are no longer plug-specific.

Signed-off-by: Caleb Sander Mateos <csander@purestorage.com>
---
 block/blk-mq.c      | 26 ++++++++++++--------------
 block/mq-deadline.c |  2 +-
 2 files changed, 13 insertions(+), 15 deletions(-)

diff --git a/block/blk-mq.c b/block/blk-mq.c
index 554380bfd002..fb514fd41d76 100644
--- a/block/blk-mq.c
+++ b/block/blk-mq.c
@@ -2788,19 +2788,19 @@ static blk_status_t blk_mq_request_issue_directly(struct request *rq, bool last)
 	if (!blk_mq_get_budget_and_tag(rq))
 		return BLK_STS_RESOURCE;
 	return __blk_mq_issue_directly(hctx, rq, last);
 }
 
-static void blk_mq_plug_issue_direct(struct blk_plug *plug)
+static void blk_mq_issue_direct(struct rq_list *rqs)
 {
 	struct blk_mq_hw_ctx *hctx = NULL;
 	struct request *rq;
 	int queued = 0;
 	blk_status_t ret = BLK_STS_OK;
 
-	while ((rq = rq_list_pop(&plug->mq_list))) {
-		bool last = rq_list_empty(&plug->mq_list);
+	while ((rq = rq_list_pop(rqs))) {
+		bool last = rq_list_empty(rqs);
 
 		if (hctx != rq->mq_hctx) {
 			if (hctx) {
 				blk_mq_commit_rqs(hctx, queued, false);
 				queued = 0;
@@ -2827,29 +2827,28 @@ static void blk_mq_plug_issue_direct(struct blk_plug *plug)
 out:
 	if (ret != BLK_STS_OK)
 		blk_mq_commit_rqs(hctx, queued, false);
 }
 
-static void __blk_mq_flush_plug_list(struct request_queue *q,
-				     struct blk_plug *plug)
+static void __blk_mq_flush_list(struct request_queue *q, struct rq_list *rqs)
 {
 	if (blk_queue_quiesced(q))
 		return;
-	q->mq_ops->queue_rqs(&plug->mq_list);
+	q->mq_ops->queue_rqs(rqs);
 }
 
-static void blk_mq_dispatch_plug_list(struct blk_plug *plug, bool from_sched)
+static void blk_mq_dispatch_list(struct rq_list *rqs, bool from_sched)
 {
 	struct blk_mq_hw_ctx *this_hctx = NULL;
 	struct blk_mq_ctx *this_ctx = NULL;
 	struct rq_list requeue_list = {};
 	unsigned int depth = 0;
 	bool is_passthrough = false;
 	LIST_HEAD(list);
 
 	do {
-		struct request *rq = rq_list_pop(&plug->mq_list);
+		struct request *rq = rq_list_pop(rqs);
 
 		if (!this_hctx) {
 			this_hctx = rq->mq_hctx;
 			this_ctx = rq->mq_ctx;
 			is_passthrough = blk_rq_is_passthrough(rq);
@@ -2858,13 +2857,13 @@ static void blk_mq_dispatch_plug_list(struct blk_plug *plug, bool from_sched)
 			rq_list_add_tail(&requeue_list, rq);
 			continue;
 		}
 		list_add_tail(&rq->queuelist, &list);
 		depth++;
-	} while (!rq_list_empty(&plug->mq_list));
+	} while (!rq_list_empty(rqs));
 
-	plug->mq_list = requeue_list;
+	*rqs = requeue_list;
 	trace_block_unplug(this_hctx->queue, depth, !from_sched);
 
 	percpu_ref_get(&this_hctx->queue->q_usage_counter);
 	/* passthrough requests should never be issued to the I/O scheduler */
 	if (is_passthrough) {
@@ -2912,23 +2911,22 @@ void blk_mq_flush_plug_list(struct blk_plug *plug, bool from_schedule)
 		 * 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_plug_list(q, plug));
+				__blk_mq_flush_list(q, &plug->mq_list));
 			if (rq_list_empty(&plug->mq_list))
 				return;
 		}
 
-		blk_mq_run_dispatch_ops(q,
-				blk_mq_plug_issue_direct(plug));
+		blk_mq_run_dispatch_ops(q, blk_mq_issue_direct(&plug->mq_list));
 		if (rq_list_empty(&plug->mq_list))
 			return;
 	}
 
 	do {
-		blk_mq_dispatch_plug_list(plug, from_schedule);
+		blk_mq_dispatch_list(&plug->mq_list, from_schedule);
 	} while (!rq_list_empty(&plug->mq_list));
 }
 
 static void blk_mq_try_issue_list_directly(struct blk_mq_hw_ctx *hctx,
 		struct list_head *list)
diff --git a/block/mq-deadline.c b/block/mq-deadline.c
index 754f6b7415cd..2edf1cac06d5 100644
--- a/block/mq-deadline.c
+++ b/block/mq-deadline.c
@@ -713,11 +713,11 @@ static void dd_insert_request(struct blk_mq_hw_ctx *hctx, struct request *rq,
 		list_add_tail(&rq->queuelist, &per_prio->fifo_list[data_dir]);
 	}
 }
 
 /*
- * Called from blk_mq_insert_request() or blk_mq_dispatch_plug_list().
+ * Called from blk_mq_insert_request() or blk_mq_dispatch_list().
  */
 static void dd_insert_requests(struct blk_mq_hw_ctx *hctx,
 			       struct list_head *list,
 			       blk_insert_t flags)
 {
-- 
2.45.2