linux-kernel - Re: [PATCH v2] blk: avoid divide-by-zero with zero granularity

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Message-ID: <yq1pn2a59u3.fsf@ca-mkp.ca.oracle.com>
Date:   Tue, 12 Jan 2021 12:46:49 -0500
From:   "Martin K. Petersen" <martin.petersen@...cle.com>
To:     Johannes Thumshirn <Johannes.Thumshirn@....com>
Cc:     Feng Li <lifeng1519@...il.com>,
        "Martin K. Petersen" <martin.petersen@...cle.com>,
        Li Feng <fengli@...rtx.com>, Jens Axboe <axboe@...nel.dk>,
        "open list:BLOCK LAYER" <linux-block@...r.kernel.org>,
        open list <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH v2] blk: avoid divide-by-zero with zero granularity


Johannes,

>> I use the nvme-tcp as the host, the target is spdk nvme-tcp target,
>> and set a wrong block size(i.g. bs=8), then the host prints this oops:
>
> I think the better fix here is to reject devices which report a block size
> small than a sector.

Yep, Linux doesn't support logical block sizes < 512 bytes.

Also, the NVMe spec states:

	"A value smaller than 9 (i.e., 512 bytes) is not supported."

-- 
Martin K. Petersen	Oracle Linux Engineering