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From: Ming Lei <ming.lei@redhat.com>
To: Sagi Grimberg <sagi@grimberg.me>
Cc: Christoph Hellwig <hch@lst.de>,
	linux-nvme@lists.infradead.org, Yi Zhang <yi.zhang@redhat.com>,
	stable@vger.kernel.org,
	Chaitanya Kulkarni <chaitanya.kulkarni@wdc.com>
Subject: Re: [PATCH 1/2] nvme: target: fix nvmet_file_init_bvec()
Date: Tue, 26 Mar 2019 10:16:28 +0800	[thread overview]
Message-ID: <20190326021627.GE30669@ming.t460p> (raw)
In-Reply-To: <a850ff6c-f006-9b1b-5425-19cc6a1693c7@grimberg.me>

On Mon, Mar 25, 2019 at 07:03:23PM -0700, Sagi Grimberg wrote:
> 
> > > The scatterlist in the nvme target is always allocated by the nvmet
> > > code itself an thus never contains multi-page sg list entries.
> > 
> > I am wondering if it is true.
> > 
> > Not look at other target code yet, however seems it isn't true for loop,
> > see the following code in nvme_loop_queue_rq():
> > 
> > 	iod->req.sg = iod->sg_table.sgl;
> > 	iod->req.sg_cnt = blk_rq_map_sg(req->q, req, iod->sg_table.sgl);
> > 	iod->req.transfer_len = blk_rq_payload_bytes(req);
> > 
> > And it has been triggered by nvme/011 in Yi's test.
> 
> Yes, loop is an exception in this case.

Thanks for the clarification!

Another candidate fix is to set nvmet-loop's queue segment boundary mask
as PAGE_SIZE - 1.

Also there is the same issue for block device backed target.

If no one objects, I'd like to take the approach of adjusting segment
boundary mask.

Thanks,
Ming

  reply	other threads:[~2019-03-26  2:16 UTC|newest]

Thread overview: 6+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <20190325100708.24172-1-ming.lei@redhat.com>
2019-03-25 10:07 ` [PATCH 1/2] nvme: target: fix nvmet_file_init_bvec() Ming Lei
2019-03-25 10:52   ` Christoph Hellwig
2019-03-26  1:39     ` Ming Lei
2019-03-26  2:03       ` Sagi Grimberg
2019-03-26  2:16         ` Ming Lei [this message]
2019-03-26  7:32           ` Christoph Hellwig

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