From: Bart Van Assche <bvanassche@acm.org>
To: SelvaKumar S <selvakuma.s1@samsung.com>,
linux-nvme@lists.infradead.org, linux-block@vger.kernel.org
Cc: Mike Snitzer <snitzer@redhat.com>,
Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
djwong@kernel.org, dm-devel@redhat.com, hch@lst.de,
agk@redhat.com, linux-scsi@vger.kernel.org,
nitheshshetty@gmail.com, willy@infradead.org,
nj.shetty@samsung.com, kch@kernel.org, selvajove@gmail.com,
mpatocka@redhat.com, javier.gonz@samsung.com, kbusch@kernel.org,
axboe@kernel.dk, damien.lemoal@wdc.com, joshi.k@samsung.com,
"Martin K. Petersen" <martin.petersen@oracle.com>,
linux-api@vger.kernel.org, johannes.thumshirn@wdc.com,
linux-fsdevel@vger.kernel.org, joshiiitr@gmail.com,
asml.silence@gmail.com
Subject: Re: [dm-devel] [PATCH 3/7] block: copy offload support infrastructure
Date: Tue, 17 Aug 2021 10:14:27 -0700 [thread overview]
Message-ID: <ad3561b9-775d-dd4d-0d92-6343440b1f8f@acm.org> (raw)
In-Reply-To: <20210817101423.12367-4-selvakuma.s1@samsung.com>
On 8/17/21 3:14 AM, SelvaKumar S wrote:
> Introduce REQ_OP_COPY, a no-merge copy offload operation. Create
> bio with control information as payload and submit to the device.
> Larger copy operation may be divided if necessary by looking at device
> limits. REQ_OP_COPY(19) is a write op and takes zone_write_lock when
> submitted to zoned device.
> Native copy offload is not supported for stacked devices.
Using a single operation for copy-offloading instead of separate
operations for reading and writing is fundamentally incompatible with
the device mapper. I think we need a copy-offloading implementation that
is compatible with the device mapper.
Storing the parameters of the copy operation in the bio payload is
incompatible with the current implementation of bio_split().
In other words, I think there are fundamental problems with this patch
series.
Bart.
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next prev parent reply other threads:[~2021-08-17 17:15 UTC|newest]
Thread overview: 30+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <CGME20210817101741epcas5p174ca0a539587da6a67b9f58cd13f2bad@epcas5p1.samsung.com>
2021-08-17 10:14 ` [dm-devel] [PATCH 0/7] add simple copy support SelvaKumar S
[not found] ` <CGME20210817101747epcas5p1242e63ec29b127b03b6f9f5f1b57f86e@epcas5p1.samsung.com>
2021-08-17 10:14 ` [dm-devel] [PATCH 1/7] block: make bio_map_kern() non static SelvaKumar S
[not found] ` <CGME20210817101753epcas5p4f4257f8edda27e184ecbb273b700ccbc@epcas5p4.samsung.com>
2021-08-17 10:14 ` [dm-devel] [PATCH 2/7] block: Introduce queue limits for copy-offload support SelvaKumar S
2021-08-17 13:08 ` Greg KH
2021-08-17 14:42 ` Nitesh Shetty
[not found] ` <CGME20210817101758epcas5p1ec353b3838d64654e69488229256d9eb@epcas5p1.samsung.com>
2021-08-17 10:14 ` [dm-devel] [PATCH 3/7] block: copy offload support infrastructure SelvaKumar S
2021-08-17 17:14 ` Bart Van Assche [this message]
2021-08-17 20:41 ` Mikulas Patocka
2021-08-17 21:53 ` Douglas Gilbert
2021-08-17 22:06 ` Bart Van Assche
2021-08-20 10:39 ` Kanchan Joshi
2021-08-20 21:18 ` Bart Van Assche
2021-08-26 7:46 ` Nitesh Shetty
2021-08-17 20:35 ` kernel test robot
2021-08-18 18:35 ` Martin K. Petersen
2021-08-20 11:11 ` Kanchan Joshi
[not found] ` <CGME20210817101803epcas5p10cda1d52f8a8f1172e34b1f9cf8eef3b@epcas5p1.samsung.com>
2021-08-17 10:14 ` [dm-devel] [PATCH 4/7] block: Introduce a new ioctl for simple copy SelvaKumar S
2021-08-17 13:09 ` Greg KH
2021-08-17 13:10 ` Greg KH
2021-08-17 14:48 ` Nitesh Shetty
2021-08-17 23:36 ` Darrick J. Wong
2021-08-18 15:37 ` Nitesh Shetty
2021-08-18 16:17 ` Darrick J. Wong
[not found] ` <CGME20210817101809epcas5p39eed3531ed82f5f08127eb3dba1fc50f@epcas5p3.samsung.com>
2021-08-17 10:14 ` [dm-devel] [PATCH 5/7] block: add emulation " SelvaKumar S
2021-08-17 22:10 ` kernel test robot
[not found] ` <CGME20210817101814epcas5p41db3d7269f5139efcaf2ca685cd04a16@epcas5p4.samsung.com>
2021-08-17 10:14 ` [dm-devel] [PATCH 6/7] nvme: add simple copy support SelvaKumar S
[not found] ` <CGME20210817101822epcas5p470644cf681d5e8db5367dc7998305c65@epcas5p4.samsung.com>
2021-08-17 10:14 ` [dm-devel] [PATCH 7/7] dm kcopyd: add simple copy offload support SelvaKumar S
2021-08-17 20:29 ` Mikulas Patocka
2021-08-17 23:37 ` [dm-devel] [PATCH 0/7] add simple copy support Darrick J. Wong
2021-08-18 15:40 ` Nitesh Shetty
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