blk-mq: Add blk_mq_alloc_map_and_rqs()

Add a function to combine allocating tags and the associated requests,
and factor out common patterns to use this new function.

Some function only call blk_mq_alloc_map_and_rqs() now, but more
functionality will be added later.

Also make blk_mq_alloc_rq_map() and blk_mq_alloc_rqs() static since they
are only used in blk-mq.c, and finally rename some functions for
conciseness and consistency with other function names:
- __blk_mq_alloc_map_and_{request -> rqs}()
- blk_mq_alloc_{map_and_requests -> set_map_and_rqs}()

Suggested-by: Ming Lei <ming.lei@redhat.com>
Signed-off-by: John Garry <john.garry@huawei.com>
Reviewed-by: Hannes Reinecke <hare@suse.de>
Reviewed-by: Ming Lei <ming.lei@redhat.com>
Link: https://lore.kernel.org/r/1633429419-228500-11-git-send-email-john.garry@huawei.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>

1 files changed, 36 insertions, 26 deletions

diff --git a/block/blk-mq.c b/block/blk-mq.c
index 59bbfc935d87..ab3a831baa9d 100644
--- a/block/blk-mq.c
+++ b/block/blk-mq.c
@@ -2392,11 +2392,11 @@ void blk_mq_free_rq_map(struct blk_mq_tags *tags, unsigned int flags)
 	blk_mq_free_tags(tags, flags);
 }
 
-struct blk_mq_tags *blk_mq_alloc_rq_map(struct blk_mq_tag_set *set,
-					unsigned int hctx_idx,
-					unsigned int nr_tags,
-					unsigned int reserved_tags,
-					unsigned int flags)
+static struct blk_mq_tags *blk_mq_alloc_rq_map(struct blk_mq_tag_set *set,
+					       unsigned int hctx_idx,
+					       unsigned int nr_tags,
+					       unsigned int reserved_tags,
+					       unsigned int flags)
 {
 	struct blk_mq_tags *tags;
 	int node;
@@ -2444,8 +2444,9 @@ static int blk_mq_init_request(struct blk_mq_tag_set *set, struct request *rq,
 	return 0;
 }
 
-int blk_mq_alloc_rqs(struct blk_mq_tag_set *set, struct blk_mq_tags *tags,
-		     unsigned int hctx_idx, unsigned int depth)
+static int blk_mq_alloc_rqs(struct blk_mq_tag_set *set,
+			    struct blk_mq_tags *tags,
+			    unsigned int hctx_idx, unsigned int depth)
 {
 	unsigned int i, j, entries_per_page, max_order = 4;
 	size_t rq_size, left;
@@ -2856,25 +2857,34 @@ static void blk_mq_init_cpu_queues(struct request_queue *q,
 	}
 }
 
-static bool __blk_mq_alloc_map_and_request(struct blk_mq_tag_set *set,
-					int hctx_idx)
+struct blk_mq_tags *blk_mq_alloc_map_and_rqs(struct blk_mq_tag_set *set,
+					     unsigned int hctx_idx,
+					     unsigned int depth)
 {
-	unsigned int flags = set->flags;
-	int ret = 0;
+	struct blk_mq_tags *tags;
+	int ret;
 
-	set->tags[hctx_idx] = blk_mq_alloc_rq_map(set, hctx_idx,
-					set->queue_depth, set->reserved_tags, flags);
-	if (!set->tags[hctx_idx])
-		return false;
+	tags = blk_mq_alloc_rq_map(set, hctx_idx, depth, set->reserved_tags,
+				   set->flags);
+	if (!tags)
+		return NULL;
 
-	ret = blk_mq_alloc_rqs(set, set->tags[hctx_idx], hctx_idx,
-				set->queue_depth);
-	if (!ret)
-		return true;
+	ret = blk_mq_alloc_rqs(set, tags, hctx_idx, depth);
+	if (ret) {
+		blk_mq_free_rq_map(tags, set->flags);
+		return NULL;
+	}
 
-	blk_mq_free_rq_map(set->tags[hctx_idx], flags);
-	set->tags[hctx_idx] = NULL;
-	return false;
+	return tags;
+}
+
+static bool __blk_mq_alloc_map_and_rqs(struct blk_mq_tag_set *set,
+				       int hctx_idx)
+{
+	set->tags[hctx_idx] = blk_mq_alloc_map_and_rqs(set, hctx_idx,
+						       set->queue_depth);
+
+	return set->tags[hctx_idx];
 }
 
 static void blk_mq_free_map_and_requests(struct blk_mq_tag_set *set,
@@ -2919,7 +2929,7 @@ static void blk_mq_map_swqueue(struct request_queue *q)
 			hctx_idx = set->map[j].mq_map[i];
 			/* unmapped hw queue can be remapped after CPU topo changed */
 			if (!set->tags[hctx_idx] &&
-			    !__blk_mq_alloc_map_and_request(set, hctx_idx)) {
+			    !__blk_mq_alloc_map_and_rqs(set, hctx_idx)) {
 				/*
 				 * If tags initialization fail for some hctx,
 				 * that hctx won't be brought online.  In this
@@ -3352,7 +3362,7 @@ static int __blk_mq_alloc_rq_maps(struct blk_mq_tag_set *set)
 	int i;
 
 	for (i = 0; i < set->nr_hw_queues; i++) {
-		if (!__blk_mq_alloc_map_and_request(set, i))
+		if (!__blk_mq_alloc_map_and_rqs(set, i))
 			goto out_unwind;
 		cond_resched();
 	}
@@ -3371,7 +3381,7 @@ out_unwind:
  * may reduce the depth asked for, if memory is tight. set->queue_depth
  * will be updated to reflect the allocated depth.
  */
-static int blk_mq_alloc_map_and_requests(struct blk_mq_tag_set *set)
+static int blk_mq_alloc_set_map_and_rqs(struct blk_mq_tag_set *set)
 {
 	unsigned int depth;
 	int err;
@@ -3537,7 +3547,7 @@ int blk_mq_alloc_tag_set(struct blk_mq_tag_set *set)
 	if (ret)
 		goto out_free_mq_map;
 
-	ret = blk_mq_alloc_map_and_requests(set);
+	ret = blk_mq_alloc_set_map_and_rqs(set);
 	if (ret)
 		goto out_free_mq_map;