[PATCH] blk-mg-tag: Make tag's codeflow more reasonably during initializing

[Minfei Huang <mhuang@redhat.com>]

From: Minfei Huang <mnfhuang@gmail.com>

It might be more reasonable to cleanup all of the allocations in same
function, if there is a fatal. Thus we can make function more
independency to export it.

For this patch, variant tag will be allocated in blk_mq_init_tags, and
it will be freed in same function, if there is an error during
initializing the tag.

What the blk_mq_init_bitmap_tags does is to allocate bitmap.

Signed-off-by: Minfei Huang <mnfhuang@gmail.com>
---
 block/blk-mq-tag.c | 30 ++++++++++++++++++------------
 1 file changed, 18 insertions(+), 12 deletions(-)

diff --git a/block/blk-mq-tag.c b/block/blk-mq-tag.c
index a07ca34..7a1d9a8 100644
--- a/block/blk-mq-tag.c
+++ b/block/blk-mq-tag.c
@@ -596,23 +596,24 @@ static void bt_free(struct blk_mq_bitmap_tags *bt)
 	kfree(bt->bs);
 }
 
-static struct blk_mq_tags *blk_mq_init_bitmap_tags(struct blk_mq_tags *tags,
-						   int node, int alloc_policy)
+static int blk_mq_init_bitmap_tags(struct blk_mq_tags *tags,
+		int node, int alloc_policy)
 {
+	int ret = 0;
 	unsigned int depth = tags->nr_tags - tags->nr_reserved_tags;
 
 	tags->alloc_policy = alloc_policy;
 
-	if (bt_alloc(&tags->bitmap_tags, depth, node, false))
-		goto enomem;
-	if (bt_alloc(&tags->breserved_tags, tags->nr_reserved_tags, node, true))
-		goto enomem;
+	ret = bt_alloc(&tags->bitmap_tags, depth, node, false);
+	if (ret)
+		goto out;
 
-	return tags;
-enomem:
-	bt_free(&tags->bitmap_tags);
-	kfree(tags);
-	return NULL;
+	ret = bt_alloc(&tags->breserved_tags,
+			tags->nr_reserved_tags, node, true);
+	if (ret)
+		bt_free(&tags->bitmap_tags);
+out:
+	return ret;
 }
 
 struct blk_mq_tags *blk_mq_init_tags(unsigned int total_tags,
@@ -638,7 +639,12 @@ struct blk_mq_tags *blk_mq_init_tags(unsigned int total_tags,
 	tags->nr_tags = total_tags;
 	tags->nr_reserved_tags = reserved_tags;
 
-	return blk_mq_init_bitmap_tags(tags, node, alloc_policy);
+	if (blk_mq_init_bitmap_tags(tags, node, alloc_policy)) {
+		kfree(tags);
+		return NULL;
+	}
+
+	return tags;
 }
 
 void blk_mq_free_tags(struct blk_mq_tags *tags)
-- 
1.8.3.1