On Tue, Sep 27, 2016 at 08:26:19AM +0200, Hannes Reinecke wrote:

On 09/26/2016 08:27 PM, Bart Van Assche wrote:

quoted

Move the blk_freeze_queue() and blk_unfreeze_queue() implementations
from block/blk-mq.c to block/blk-core.c. Drop "_mq" from the name of
the functions that have been moved.

Signed-off-by: Bart Van Assche <redacted>
---
 block/blk-core.c | 45 +++++++++++++++++++++++++++++++++++++++++++++
 block/blk-mq.c   | 41 +++--------------------------------------
 block/blk.h      |  3 +++
 3 files changed, 51 insertions(+), 38 deletions(-)

diff --git a/block/blk-core.c b/block/blk-core.c
index b75d688..8cc8006 100644
--- a/block/blk-core.c
+++ b/block/blk-core.c

@@ -682,6 +682,51 @@ static void blk_queue_usage_counter_release(struct percpu_ref *ref)
 	wake_up_all(&q->mq_freeze_wq);
 }
 
+void blk_freeze_queue_start(struct request_queue *q)
+{
+	int freeze_depth;
+
+	freeze_depth = atomic_inc_return(&q->mq_freeze_depth);
+	if (freeze_depth == 1) {
+		percpu_ref_kill(&q->q_usage_counter);
+		blk_mq_run_hw_queues(q, false);
+	}
+}
+

As you dropped the 'mq_' prefix, maybe you should rename the counter to
'freeze_depth', to?

See PATCH 6/9

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Johannes Thumshirn                                          Storage
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