linux-kernel - Re: [PATCH] block: don't check position contiguity for DISCARD in attempt

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Date:   Fri, 19 Oct 2018 11:57:18 -0400
From:   "Martin K. Petersen" <martin.petersen@...cle.com>
To:     Jianchao Wang <jianchao.w.wang@...cle.com>
Cc:     axboe@...nel.dk, linux-block@...r.kernel.org,
        linux-kernel@...r.kernel.org
Subject: Re: [PATCH] block: don't check position contiguity for DISCARD in attempt_merge


Jianchao,

> Discard command supports multiple ranges of blocks, so needn't
> checking position contiguity when merging. Let's do the same thing
> in attempt_merge as the blk_try_merge.

Discards need to be contiguous unless queue->limits.max_discard_segments
is bigger than 1. So if you remove this I think you need to add a
contiguity check in req_attempt_discard_merge().

-- 
Martin K. Petersen	Oracle Linux Engineering