From: Christoph Hellwig <hch@lst.de>
To: Ming Lei <ming.lei@redhat.com>
Cc: Jens Axboe <axboe@kernel.dk>, Christoph Hellwig <hch@lst.de>,
linux-block@vger.kernel.org,
Wang Shanker <shankerwangmiao@gmail.com>
Subject: Re: [PATCH 1/2] block: fix discard request merge
Date: Tue, 22 Jun 2021 08:53:09 +0200 [thread overview]
Message-ID: <20210622065309.GA29691@lst.de> (raw)
In-Reply-To: <20210609004556.46928-2-ming.lei@redhat.com>
On Wed, Jun 09, 2021 at 08:45:55AM +0800, Ming Lei wrote:
> index 4d97fb6dd226..bcdff1879c34 100644
> --- a/block/blk-merge.c
> +++ b/block/blk-merge.c
> @@ -559,10 +559,14 @@ static inline unsigned int blk_rq_get_max_segments(struct request *rq)
> static inline int ll_new_hw_segment(struct request *req, struct bio *bio,
> unsigned int nr_phys_segs)
> {
> - if (req->nr_phys_segments + nr_phys_segs > blk_rq_get_max_segments(req))
> + if (blk_integrity_merge_bio(req->q, req, bio) == false)
> goto no_merge;
>
> - if (blk_integrity_merge_bio(req->q, req, bio) == false)
> + /* discard request merge won't add new segment */
> + if (req_op(req) == REQ_OP_DISCARD)
> + return 1;
> +
> + if (req->nr_phys_segments + nr_phys_segs > blk_rq_get_max_segments(req))
I'd rather handle this by returning UINT_MAX for discard requests from
blk_rq_get_max_segments given that bio_attempt_discard_merge is only used
for the !DISCARD_MERGE case anyway.
next prev parent reply other threads:[~2021-06-22 6:53 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-06-09 0:45 [PATCH 0/2] block: discard merge fix & improvement Ming Lei
2021-06-09 0:45 ` [PATCH 1/2] block: fix discard request merge Ming Lei
2021-06-22 6:53 ` Christoph Hellwig [this message]
2021-06-22 7:51 ` Ming Lei
2021-06-09 0:45 ` [PATCH 2/2] block: support bio merge for multi-range discard Ming Lei
2021-06-09 3:05 ` Wang Shanker
2021-06-09 6:12 ` Ming Lei
2021-06-09 6:57 ` Wang Shanker
2021-06-22 6:55 ` Christoph Hellwig
2021-06-22 8:35 ` Miao Wang
2021-06-14 22:00 ` [PATCH 0/2] block: discard merge fix & improvement Ming Lei
2021-06-22 3:53 ` Ming Lei
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