[PATCH 08/14] blk-mq: add blk_mq_resize_tag_set()

[Hannes Reinecke <hare@suse.de>]

Add a function to resize the number of tags in an existing tag set.

Signed-off-by: Hannes Reinecke <hare@suse.com>
---
 block/blk-mq.c         | 15 +++++++++++++++
 include/linux/blk-mq.h |  1 +
 2 files changed, 16 insertions(+)

diff --git a/block/blk-mq.c b/block/blk-mq.c
index 29cbc1b..e2afe45 100644
--- a/block/blk-mq.c
+++ b/block/blk-mq.c
@@ -2385,6 +2385,21 @@ void blk_mq_update_nr_hw_queues(struct blk_mq_tag_set *set, int nr_hw_queues)
 }
 EXPORT_SYMBOL_GPL(blk_mq_update_nr_hw_queues);
 
+int blk_mq_resize_tag_set(struct blk_mq_tag_set *set, int new_tags)
+{
+	int i, ret = 0;
+
+	for (i = 0; i < set->nr_hw_queues; i++) {
+		if (!set->tags[i])
+			continue;
+		ret = blk_mq_tag_update_depth(set->tags[i], new_tags);
+		if (ret)
+			break;
+	}
+	return ret;
+}
+EXPORT_SYMBOL(blk_mq_resize_tag_set);
+
 void blk_mq_disable_hotplug(void)
 {
 	mutex_lock(&all_q_mutex);
diff --git a/include/linux/blk-mq.h b/include/linux/blk-mq.h
index 2498fdf..8b603b6 100644
--- a/include/linux/blk-mq.h
+++ b/include/linux/blk-mq.h
@@ -181,6 +181,7 @@ void blk_mq_unregister_disk(struct gendisk *);
 
 int blk_mq_alloc_tag_set(struct blk_mq_tag_set *set);
 void blk_mq_free_tag_set(struct blk_mq_tag_set *set);
+int blk_mq_resize_tag_set(struct blk_mq_tag_set *set, int new_tags);
 
 void blk_mq_flush_plug_list(struct blk_plug *plug, bool from_schedule);
 
-- 
1.8.5.6