diff mbox

[RFC,1/4] blk-mq: introduce blk_mq_support_runtime_pm()

Message ID 20180711162906.14271-2-ming.lei@redhat.com (mailing list archive)
State New, archived
Headers show

Commit Message

Ming Lei July 11, 2018, 4:29 p.m. UTC 
A bit cost has to be added in fast IO path for supporting runtime PM, and
introduce this helper so that drivers incapable of runtime PM may not be
affected by this feature.

Cc: "Rafael J. Wysocki" <rjw@rjwysocki.net>
Cc: Alan Stern <stern@rowland.harvard.edu>
Cc: linux-pm@vger.kernel.org
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Bart Van Assche <bart.vanassche@wdc.com>
Cc: "James E.J. Bottomley" <jejb@linux.vnet.ibm.com>
Cc: "Martin K. Petersen" <martin.petersen@oracle.com>
Cc: linux-scsi@vger.kernel.org
Signed-off-by: Ming Lei <ming.lei@redhat.com>
---
 include/linux/blk-mq.h | 10 ++++++++++
 1 file changed, 10 insertions(+)

Comments

Christoph Hellwig July 11, 2018, 5:10 p.m. UTC | #1 
On Thu, Jul 12, 2018 at 12:29:03AM +0800, Ming Lei wrote:
> A bit cost has to be added in fast IO path for supporting runtime PM, and
> introduce this helper so that drivers incapable of runtime PM may not be
> affected by this feature.

I don't think this is useful on it's own and should go with the
patch that uses it.
diff mbox

Patch

diff --git a/include/linux/blk-mq.h b/include/linux/blk-mq.h
index d710e92874cc..998ad6602448 100644
--- a/include/linux/blk-mq.h
+++ b/include/linux/blk-mq.h
@@ -180,6 +180,7 @@  enum {
 	BLK_MQ_F_SHOULD_MERGE	= 1 << 0,
 	BLK_MQ_F_TAG_SHARED	= 1 << 1,
 	BLK_MQ_F_SG_MERGE	= 1 << 2,
+	BLK_MQ_F_SUPPORT_RPM	= 1 << 3,
 	BLK_MQ_F_BLOCKING	= 1 << 5,
 	BLK_MQ_F_NO_SCHED	= 1 << 6,
 	BLK_MQ_F_ALLOC_POLICY_START_BIT = 8,
@@ -249,6 +250,15 @@  static inline u16 blk_mq_unique_tag_to_tag(u32 unique_tag)
 	return unique_tag & BLK_MQ_UNIQUE_TAG_MASK;
 }
 
+static inline bool blk_mq_support_runtime_pm(struct request_queue *q)
+{
+	struct blk_mq_tag_set *set = q->tag_set;
+
+	if (!q->dev || !set || !(set->flags & BLK_MQ_F_SUPPORT_RPM))
+		return false;
+
+	return true;
+}
 
 int blk_mq_request_started(struct request *rq);
 void blk_mq_start_request(struct request *rq);