Re: [PATCH 2/4] block: avoid to merge splitted bio

[Jeff Moyer <jmoyer@redhat.com>]

Ming Lei <ming.lei@canonical.com> writes:

> The splitted bio has been already too fat to merge, so mark it
> as NOMERGE.
>
> Signed-off-by: Ming Lei <ming.lei@canonical.com>

Reviewed-by: Jeff Moyer <jmoyer@redhat.com>

> ---
>  block/blk-merge.c | 3 +++
>  1 file changed, 3 insertions(+)
>
> diff --git a/block/blk-merge.c b/block/blk-merge.c
> index 22293fd..de5716d8 100644
> --- a/block/blk-merge.c
> +++ b/block/blk-merge.c
> @@ -139,6 +139,9 @@ void blk_queue_split(struct request_queue *q, struct bio **bio,
>  	bio_set_flag(res, BIO_SEG_VALID);
>  
>  	if (split) {
> +		/* there isn't chance to merge the splitted bio */
> +		split->bi_rw |= REQ_NOMERGE;
> +
>  		bio_chain(split, *bio);
>  		generic_make_request(*bio);
>  		*bio = split;