On 4/8/23 08:58, Bart Van Assche wrote:
> Requeue requests instead of sending these to the dispatch list if a CPU
> is unplugged to prevent reordering of zoned writes.
>
> Cc: Christoph Hellwig <hch@xxxxxx>
> Cc: Damien Le Moal <damien.lemoal@xxxxxxxxxxxxxxxxxx>
> Cc: Ming Lei <ming.lei@xxxxxxxxxx>
> Cc: Mike Snitzer <snitzer@xxxxxxxxxx>
> Signed-off-by: Bart Van Assche <bvanassche@xxxxxxx>
Looks OK.
Reviewed-by: Damien Le Moal <dlemoal@xxxxxxxxxx>
> ---
> block/blk-mq.c | 14 +++++++++++---
> 1 file changed, 11 insertions(+), 3 deletions(-)
>
> diff --git a/block/blk-mq.c b/block/blk-mq.c
> index 57315395434b..77fdaed4e074 100644
> --- a/block/blk-mq.c
> +++ b/block/blk-mq.c
> @@ -3495,9 +3495,17 @@ static int blk_mq_hctx_notify_dead(unsigned int cpu, struct hlist_node *node)
> if (list_empty(&tmp))
> return 0;
>
> - spin_lock(&hctx->lock);
> - list_splice_tail_init(&tmp, &hctx->dispatch);
> - spin_unlock(&hctx->lock);
> + if (hctx->queue->elevator) {
> + struct request *rq, *next;
> +
> + list_for_each_entry_safe(rq, next, &tmp, queuelist)
> + blk_mq_requeue_request(rq, false);
> + blk_mq_kick_requeue_list(hctx->queue);
> + } else {
> + spin_lock(&hctx->lock);
> + list_splice_tail_init(&tmp, &hctx->dispatch);
> + spin_unlock(&hctx->lock);
> + }
>
> blk_mq_run_hw_queue(hctx, true);
> return 0;
