On Mon, Dec 17, 2018 at 12:16:26PM +0100, Christoph Hellwig wrote:
> We should check if a given queue map actually has queues enabled before
> dispatching to it. This allows drivers to not initialize optional but
> not used map types, which subsequently will allow fixing problems with
> queue map rebuilds for that case.
>
> Signed-off-by: Christoph Hellwig <hch@xxxxxx>
> ---
> block/blk-mq.h | 13 ++++++++-----
> 1 file changed, 8 insertions(+), 5 deletions(-)
>
> diff --git a/block/blk-mq.h b/block/blk-mq.h
> index b63a0de8a07a..d1ed096723fb 100644
> --- a/block/blk-mq.h
> +++ b/block/blk-mq.h
> @@ -105,14 +105,17 @@ static inline struct blk_mq_hw_ctx *blk_mq_map_queue(struct request_queue *q,
> {
> enum hctx_type type = HCTX_TYPE_DEFAULT;
>
> - if (q->tag_set->nr_maps > HCTX_TYPE_POLL &&
> - ((flags & REQ_HIPRI) && test_bit(QUEUE_FLAG_POLL, &q->queue_flags)))
> + if ((flags & REQ_HIPRI) &&
> + q->tag_set->nr_maps > HCTX_TYPE_POLL &&
> + q->tag_set->map[HCTX_TYPE_POLL].nr_queues &&
> + test_bit(QUEUE_FLAG_POLL, &q->queue_flags))
> type = HCTX_TYPE_POLL;
>
> - else if (q->tag_set->nr_maps > HCTX_TYPE_READ &&
> - ((flags & REQ_OP_MASK) == REQ_OP_READ))
> + else if (((flags & REQ_OP_MASK) == REQ_OP_READ) &&
> + q->tag_set->nr_maps > HCTX_TYPE_READ &&
> + q->tag_set->map[HCTX_TYPE_READ].nr_queues)
> type = HCTX_TYPE_READ;
> -
> +
> return blk_mq_map_queue_type(q, type, cpu);
> }
Reviewed-by: Ming Lei <ming.lei@xxxxxxxxxx>
Thanks,
Ming
