From: Jens Axboe <axboe@kernel.dk>
To: Ming Lei <ming.lei@redhat.com>
Cc: linux-block@vger.kernel.org, Christoph Hellwig <hch@lst.de>,
Wang Shanker <shankerwangmiao@gmail.com>
Subject: Re: [PATCH RESEND] block: fix discard request merge
Date: Tue, 29 Jun 2021 07:41:29 -0600 [thread overview]
Message-ID: <d3087bbe-a577-1f9b-561d-49d99f4dba62@kernel.dk> (raw)
In-Reply-To: <20210628023312.1903255-1-ming.lei@redhat.com>
On 6/27/21 8:33 PM, Ming Lei wrote:
> ll_new_hw_segment() is reached only in case of single range discard
> merge, and we don't have max discard segment size limit actually, so
> it is wrong to run the following check:
>
> if (req->nr_phys_segments + nr_phys_segs > blk_rq_get_max_segments(req))
>
> it may be always false since req->nr_phys_segments is initialized as
> one, and bio's segment count is still 1, blk_rq_get_max_segments(reg)
> is 1 too.
>
> Fix the issue by not doing the check and bypassing the calculation of
> discard request's nr_phys_segments.
>
> Based on analysis from Wang Shanker.
Applied, thanks.
--
Jens Axboe
prev parent reply other threads:[~2021-06-29 13:41 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-06-28 2:33 [PATCH RESEND] block: fix discard request merge Ming Lei
2021-06-29 13:41 ` Jens Axboe [this message]
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