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>
diff --git a/include/linux/blk-mq.h b/include/linux/blk-mq.h
index a06ca7b..f454244 100644
--- a/include/linux/blk-mq.h
+++ b/include/linux/blk-mq.h
@@ -63,7 +63,7 @@
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;