On 06/19/2017 04:08 PM, Bart Van Assche wrote:
> From: Bart Van Assche <bart.vanassche@xxxxxxxxxxx>
>
> A queue must be frozen while the mapped state of a hardware queue
> is changed. Additionally, any change of the mapped state is
> followed by a call to blk_mq_map_swqueue() (see also
> blk_mq_init_allocated_queue() and blk_mq_update_nr_hw_queues()).
> Since blk_mq_map_swqueue() does not map any unmapped hardware
> queue onto any software queue, no attempt will be made to run
> an unmapped hardware queue. Hence issue a warning upon attempts
> to run an unmapped hardware queue.
>
> Signed-off-by: Bart Van Assche <bart.vanassche@xxxxxxxxxxx>
> Reviewed-by: Christoph Hellwig <hch@xxxxxx>
> Cc: Hannes Reinecke <hare@xxxxxxxx>
> Cc: Omar Sandoval <osandov@xxxxxx>
> Cc: Ming Lei <ming.lei@xxxxxxxxxx>
> ---
> block/blk-mq.c | 7 ++++---
> 1 file changed, 4 insertions(+), 3 deletions(-)
>
> diff --git a/block/blk-mq.c b/block/blk-mq.c
> index e7b0d69fdf65..c6218f32770d 100644
> --- a/block/blk-mq.c
> +++ b/block/blk-mq.c
> @@ -1140,8 +1140,9 @@ static int blk_mq_hctx_next_cpu(struct blk_mq_hw_ctx *hctx)
> static void __blk_mq_delay_run_hw_queue(struct blk_mq_hw_ctx *hctx, bool async,
> unsigned long msecs)
> {
> - if (unlikely(blk_mq_hctx_stopped(hctx) ||
> - !blk_mq_hw_queue_mapped(hctx)))
> + WARN_ON_ONCE(!blk_mq_hw_queue_mapped(hctx));
> +
if (WARN_ON_ONCE(!blk_mq_hw_queue_mapped(hctx)))
return;
--
Jens Axboe
