From: Christoph Hellwig <hch@lst.de>
To: Logan Gunthorpe <logang@deltatee.com>
Cc: Sagi Grimberg <sagi@grimberg.me>,
Chaitanya Kulkarni <chaitanya.kulkarni@wdc.com>,
Christoph Hellwig <hch@lst.de>,
linux-nvme@lists.infradead.org,
Douglas Gilbert <dgilbert@interlog.com>
Subject: Re: [PATCH] nvmet-passthru: Cleanup nvmet_passthru_map_sg()
Date: Thu, 15 Oct 2020 20:01:48 +0200 [thread overview]
Message-ID: <20201015180148.GA23377@lst.de> (raw)
In-Reply-To: <bc51aadc-eee3-cf52-0623-b3f82e1958f4@deltatee.com>
On Thu, Oct 15, 2020 at 10:01:30AM -0600, Logan Gunthorpe wrote:
>
>
> On 2020-10-15 1:56 a.m., Christoph Hellwig wrote:
> > On Fri, Oct 09, 2020 at 05:18:16PM -0600, Logan Gunthorpe wrote:
> >> static int nvmet_passthru_map_sg(struct nvmet_req *req, struct request *rq)
> >> {
> >> - int sg_cnt = req->sg_cnt;
> >> struct scatterlist *sg;
> >> int op_flags = 0;
> >> struct bio *bio;
> >> int i, ret;
> >>
> >> + if (req->sg_cnt > BIO_MAX_PAGES)
> >> + return -EINVAL;
> >
> > Don't you need to handle larger requests as well? Or at least
> > limit MDTS?
>
> No and Yes: there is already code in nvmet_passthru_override_id_ctrl()
> to limit MDTS based on max_segments and max_hw_sectors.
But those are entirely unrelated to the bio size. BIO_MAX_PAGES is
256, so with 4k pages and assuming none can't be merged that is 1MB,
while max_segments/max_hw_sectors could be something much larger.
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next prev parent reply other threads:[~2020-10-15 18:01 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-10-09 23:18 [PATCH] nvmet-passthru: Cleanup nvmet_passthru_map_sg() Logan Gunthorpe
2020-10-13 22:26 ` Sagi Grimberg
2020-10-13 22:38 ` Douglas Gilbert
2020-10-14 0:16 ` Chaitanya Kulkarni
2020-10-14 0:20 ` Logan Gunthorpe
2020-10-14 0:25 ` Chaitanya Kulkarni
2020-10-14 15:47 ` Logan Gunthorpe
2020-10-15 7:56 ` Christoph Hellwig
2020-10-15 16:01 ` Logan Gunthorpe
2020-10-15 17:24 ` Douglas Gilbert
2020-10-15 18:01 ` Christoph Hellwig [this message]
2020-10-15 18:40 ` Logan Gunthorpe
2020-10-16 13:57 ` Christoph Hellwig
2020-10-16 16:49 ` Logan Gunthorpe
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