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/block/blk.h b/block/blk.h
index 95cab70..45385e9 100644
--- a/block/blk.h
+++ b/block/blk.h
@@ -188,6 +188,8 @@
return q->nr_congestion_off;
}
+extern int blk_update_nr_requests(struct request_queue *, unsigned int);
+
/*
* Contribute to IO statistics IFF:
*