From: Christoph Hellwig <hch@lst.de>
To: Chaitanya Kulkarni <Chaitanya.Kulkarni@wdc.com>
Cc: "Martin K. Petersen" <martin.petersen@oracle.com>,
Christoph Hellwig <hch@lst.de>, Ming Lei <ming.lei@redhat.com>,
"linux-block@vger.kernel.org" <linux-block@vger.kernel.org>,
"linux-nvme@lists.infradead.org" <linux-nvme@lists.infradead.org>,
Bart Van Assche <bvanassche@acm.org>
Subject: Re: Regression: NVMe: kernel BUG at lib/sg_pool.c:103!
Date: Thu, 21 Feb 2019 14:37:00 +0100 [thread overview]
Message-ID: <20190221133700.GA20189@lst.de> (raw)
In-Reply-To: <722BE5B7-B32B-4B2F-9AC2-E6F5AB5E12D4@wdc.com>
On Thu, Feb 21, 2019 at 01:29:57AM +0000, Chaitanya Kulkarni wrote:
> Hi Martin,
>
> I don't mind going though that route, here are some points about
> benefits of not using REQ_SPECIAL_PAYLOAD for write-zeroes :-
>
> 1. We are using RQF_SPECIAL_PAYLOAD for only discard commands and not for
> write-zeroes because it does not have any payload. Using this in the code will
> trigger more code changes to handle in the completion path.
Yes. And that is the big difference to SCSI where REQ_OP_WRITE_ZEROES
turns into a WRITE SAME command that has a payload. So for SCSI
RQF_SPECIAL_PAYLOAD for REQ_OP_WRITE_ZEROES makes a lot of sense, for
NVMe it does not.
next prev parent reply other threads:[~2019-02-21 13:37 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-02-20 3:11 Regression: NVMe: kernel BUG at lib/sg_pool.c:103! Ming Lei
2019-02-20 3:13 ` Ming Lei
2019-02-20 14:17 ` Christoph Hellwig
2019-02-20 16:59 ` Chaitanya Kulkarni
2019-02-20 18:16 ` Chaitanya Kulkarni
2019-02-20 22:55 ` Martin K. Petersen
2019-02-21 1:29 ` Chaitanya Kulkarni
2019-02-21 13:37 ` Christoph Hellwig [this message]
2019-02-21 14:22 ` Martin K. Petersen
2019-02-21 2:16 ` Ming Lei
2019-02-21 2:21 ` Chaitanya Kulkarni
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