On Wed, Feb 03 2021 at 10:53am -0500,
Sergei Shtepa <sergei.shtepa@xxxxxxxxx> wrote:
> blk_mq_is_queue_frozen() allow to assert that the queue is frozen.
>
> Signed-off-by: Sergei Shtepa <sergei.shtepa@xxxxxxxxx>
> ---
> block/blk-mq.c | 13 +++++++++++++
> include/linux/blk-mq.h | 1 +
> 2 files changed, 14 insertions(+)
>
> diff --git a/block/blk-mq.c b/block/blk-mq.c
> index f285a9123a8b..924ec26fae5f 100644
> --- a/block/blk-mq.c
> +++ b/block/blk-mq.c
> @@ -161,6 +161,19 @@ int blk_mq_freeze_queue_wait_timeout(struct request_queue *q,
> }
> EXPORT_SYMBOL_GPL(blk_mq_freeze_queue_wait_timeout);
>
> +
> +bool blk_mq_is_queue_frozen(struct request_queue *q)
> +{
> + bool ret;
> +
> + mutex_lock(&q->mq_freeze_lock);
> + ret = percpu_ref_is_dying(&q->q_usage_counter) && percpu_ref_is_zero(&q->q_usage_counter);
> + mutex_unlock(&q->mq_freeze_lock);
> +
> + return ret;
> +}
> +EXPORT_SYMBOL_GPL(blk_mq_is_queue_frozen);
> +
> /*
> * Guarantee no request is in use, so we can change any data structure of
> * the queue afterward.
> diff --git a/include/linux/blk-mq.h b/include/linux/blk-mq.h
> index d705b174d346..9d1e8c4e922e 100644
> --- a/include/linux/blk-mq.h
> +++ b/include/linux/blk-mq.h
> @@ -525,6 +525,7 @@ void blk_freeze_queue_start(struct request_queue *q);
> void blk_mq_freeze_queue_wait(struct request_queue *q);
> int blk_mq_freeze_queue_wait_timeout(struct request_queue *q,
> unsigned long timeout);
> +bool blk_mq_is_queue_frozen(struct request_queue *q);
>
> int blk_mq_map_queues(struct blk_mq_queue_map *qmap);
> void blk_mq_update_nr_hw_queues(struct blk_mq_tag_set *set, int nr_hw_queues);
> --
> 2.20.1
>
This needs to come before patch 2 (since patch 2 uses it).
Mike
