blk-mq: allow changing of queue depth through sysfs

For request_fn based devices, the block layer exports a 'nr_requests'
file through sysfs to allow adjusting of queue depth on the fly.
Currently this returns -EINVAL for blk-mq, since it's not wired up.
Wire this up for blk-mq, so that it now also always dynamic
adjustments of the allowed queue depth for any given block device
managed by blk-mq.

Signed-off-by: Jens Axboe <axboe@fb.com>

1 files changed, 1 insertions, 1 deletions

diff --git a/include/linux/blk-mq.h b/include/linux/blk-mq.h
index a06ca7b5ea05..f45424453338 100644
--- a/include/linux/blk-mq.h
+++ b/include/linux/blk-mq.h
@@ -63,7 +63,7 @@ struct blk_mq_hw_ctx {
 struct blk_mq_tag_set {
         struct blk_mq_ops       *ops;
         unsigned int            nr_hw_queues;
-        unsigned int            queue_depth;
+        unsigned int            queue_depth;    /* max hw supported */
         unsigned int            reserved_tags;
         unsigned int            cmd_size;       /* per-request extra data */
         int                     numa_node;