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From: Matthew Wilcox <willy@infradead.org>
To: SelvaKumar S <selvakuma.s1@samsung.com>
Cc: axboe@kernel.dk, damien.lemoal@wdc.com, kch@kernel.org,
	sagi@grimberg.me, snitzer@redhat.com, selvajove@gmail.com,
	linux-kernel@vger.kernel.org, linux-nvme@lists.infradead.org,
	nj.shetty@samsung.com, linux-block@vger.kernel.org,
	linux-fsdevel@vger.kernel.org, dm-devel@redhat.com,
	joshi.k@samsung.com, javier.gonz@samsung.com, kbusch@kernel.org,
	joshiiitr@gmail.com, hch@lst.de
Subject: Re: [RFC PATCH v5 3/4] nvme: add simple copy support
Date: Sat, 20 Feb 2021 03:36:37 +0000	[thread overview]
Message-ID: <20210220033637.GA2858050@casper.infradead.org> (raw)
In-Reply-To: <20210219124517.79359-4-selvakuma.s1@samsung.com>

On Fri, Feb 19, 2021 at 06:15:16PM +0530, SelvaKumar S wrote:
> +	struct nvme_copy_range *range = NULL;
[...]
> +	range = kmalloc_array(nr_range, sizeof(*range),
> +			GFP_ATOMIC | __GFP_NOWARN);
[...]
> +	req->special_vec.bv_page = virt_to_page(range);
> +	req->special_vec.bv_offset = offset_in_page(range);
> +	req->special_vec.bv_len = sizeof(*range) * nr_range;
[...]
> +struct nvme_copy_range {
> +	__le64			rsvd0;
> +	__le64			slba;
> +	__le16			nlb;
> +	__le16			rsvd18;
> +	__le32			rsvd20;
> +	__le32			eilbrt;
> +	__le16			elbat;
> +	__le16			elbatm;
> +};

so ... at 32 bytes, you can get 128 per 4kB page.  What happens if you
try to send down a command that attempts to copy 129 ranges?

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  reply	other threads:[~2021-02-20  3:37 UTC|newest]

Thread overview: 29+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <CGME20210219124555epcas5p1334e7c4d64ada5dc4a2ca0feb48c1d44@epcas5p1.samsung.com>
2021-02-19 12:45 ` [RFC PATCH v5 0/4] " SelvaKumar S
     [not found]   ` <CGME20210219124559epcas5p41da46f1c248e334953d407a154697903@epcas5p4.samsung.com>
2021-02-19 12:45     ` [RFC PATCH v5 1/4] block: make bio_map_kern() non static SelvaKumar S
     [not found]   ` <CGME20210219124603epcas5p33add0f2c1781b2a4d71bf30c9e1ac647@epcas5p3.samsung.com>
2021-02-19 12:45     ` [RFC PATCH v5 2/4] block: add simple copy support SelvaKumar S
2021-02-20  4:59       ` Damien Le Moal
2021-04-07 11:32         ` Selva Jove
2021-04-12  0:24           ` Damien Le Moal
2021-04-12 14:34             ` Selva Jove
2021-04-13  0:32               ` Damien Le Moal
2021-04-14  6:58                 ` Selva Jove
     [not found]   ` <CGME20210219124608epcas5p2a673f9e00c3e7b5352f115497b0e2d98@epcas5p2.samsung.com>
2021-02-19 12:45     ` [RFC PATCH v5 3/4] nvme: " SelvaKumar S
2021-02-20  3:36       ` Matthew Wilcox [this message]
2021-02-22 15:57         ` Selva Jove
     [not found]   ` <CGME20210219124611epcas5p1c775b63b537e75da161556e375fcf05e@epcas5p1.samsung.com>
2021-02-19 12:45     ` [RFC PATCH v5 4/4] dm kcopyd: add simple copy offload support SelvaKumar S
2021-02-20 18:01   ` [RFC PATCH v5 0/4] add simple copy support David Laight
2021-02-20 19:08     ` Matthew Wilcox
2021-02-20 19:19     ` Keith Busch
2021-02-21 23:52   ` Dave Chinner
2021-02-23  9:14     ` Selva Jove
2021-02-22  1:31   ` Ming Lei
2021-02-22  6:52   ` Su Yue
2021-02-23  9:00     ` Selva Jove
2021-04-10  0:21   ` Max Gurtovoy
2021-04-10  0:29     ` Chaitanya Kulkarni
2021-04-10  6:32       ` Javier González
2021-04-11  9:10         ` Max Gurtovoy
2021-04-11 19:26           ` Javier González
2021-04-13 15:38             ` Max Gurtovoy
2021-04-13 18:25               ` Javier González
2021-04-13 18:36                 ` Chaitanya Kulkarni

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