[PATCH 4.12 056/106] block: disable runtime-pm for blk-mq

[Greg Kroah-Hartman]

4.12-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Christoph Hellwig <hch@xxxxxx>

commit 765e40b675a9566459ddcb8358ad16f3b8344bbe upstream.

The blk-mq code lacks support for looking at the rpm_status field, tracking
active requests and the RQF_PM flag.

Due to the default switch to blk-mq for scsi people start to run into
suspend / resume issue due to this fact, so make sure we disable the runtime
PM functionality until it is properly implemented.

Signed-off-by: Christoph Hellwig <hch@xxxxxx>
Reviewed-by: Ming Lei <ming.lei@xxxxxxxxxx>
Signed-off-by: Jens Axboe <axboe@xxxxxxxxx>
Cc: Oleksandr Natalenko <oleksandr@xxxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

---
 block/blk-core.c |    4 ++++
 1 file changed, 4 insertions(+)

--- a/block/blk-core.c
+++ b/block/blk-core.c
@@ -3307,6 +3307,10 @@ EXPORT_SYMBOL(blk_finish_plug);
  */
 void blk_pm_runtime_init(struct request_queue *q, struct device *dev)
 {
+	/* not support for RQF_PM and ->rpm_status in blk-mq yet */
+	if (q->mq_ops)
+		return;
+
 	q->dev = dev;
 	q->rpm_status = RPM_ACTIVE;
 	pm_runtime_set_autosuspend_delay(q->dev, -1);