[PATCH 4/9] block: Move blk_freeze_queue() and blk_unfreeze_queue() code

[Hannes Reinecke]

On 09/26/2016 08:27 PM, Bart Van Assche wrote:
> 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 <bart.vanassche at sandisk.com>
> ---
>  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?
And are you sure this works in the !mq case, too?

> +void blk_freeze_queue_wait(struct request_queue *q)
> +{
> +	wait_event(q->mq_freeze_wq, percpu_ref_is_zero(&q->q_usage_counter));
> +}
> +
Same here, rename ->mq_freeze_wq to ->freeze_wq.

Cheers,

Hannes
-- 
Dr. Hannes Reinecke		   Teamlead Storage & Networking
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