On 9/29/22 16:47, Pankaj Raghav wrote:
> Use blk_mq_plug() wrapper to get the plug instead of directly accessing
> it in the block layer.
>
> Either of the changes should not have led to a bug in zoned devices:
>
> - blk_execute_rq_nowait:
> Only passthrough requests can use this function, and plugging can be
> performed on those requests in zoned devices. So no issues directly
> accessing the plug.
>
> - blk_flush_plug in bio_poll:
> As we don't plug the requests that require a zone lock in the first
> place, flushing should not have any impact. So no issues directly
> accessing the plug.
>
> This is just a cleanup patch to use this wrapper to get the plug
> consistently across the block layer.
>
> Signed-off-by: Pankaj Raghav <p.raghav@xxxxxxxxxxx>
Reviewed-by: Damien Le Moal <damien.lemoal@xxxxxxxxxxxxxxxxxx>
> ---
> block/blk-core.c | 2 +-
> block/blk-mq.c | 6 ++++--
> 2 files changed, 5 insertions(+), 3 deletions(-)
>
> diff --git a/block/blk-core.c b/block/blk-core.c
> index 203be672da52..d0e97de216db 100644
> --- a/block/blk-core.c
> +++ b/block/blk-core.c
> @@ -850,7 +850,7 @@ int bio_poll(struct bio *bio, struct io_comp_batch *iob, unsigned int flags)
> !test_bit(QUEUE_FLAG_POLL, &q->queue_flags))
> return 0;
>
> - blk_flush_plug(current->plug, false);
> + blk_flush_plug(blk_mq_plug(bio), false);
>
> if (bio_queue_enter(bio))
> return 0;
> diff --git a/block/blk-mq.c b/block/blk-mq.c
> index c11949d66163..5bf245c4bf0a 100644
> --- a/block/blk-mq.c
> +++ b/block/blk-mq.c
> @@ -1209,12 +1209,14 @@ static void blk_add_rq_to_plug(struct blk_plug *plug, struct request *rq)
> */
> void blk_execute_rq_nowait(struct request *rq, bool at_head)
> {
> + struct blk_plug *plug = blk_mq_plug(rq->bio);
> +
> WARN_ON(irqs_disabled());
> WARN_ON(!blk_rq_is_passthrough(rq));
>
> blk_account_io_start(rq);
> - if (current->plug)
> - blk_add_rq_to_plug(current->plug, rq);
> + if (plug)
> + blk_add_rq_to_plug(plug, rq);
> else
> blk_mq_sched_insert_request(rq, at_head, true, false);
> }
--
Damien Le Moal
Western Digital Research
