From: Sagi Grimberg <sagig@dev.mellanox.co.il>
To: "Martin K. Petersen" <martin.petersen@oracle.com>
Cc: "Nicholas A. Bellinger" <nab@daterainc.com>,
target-devel <target-devel@vger.kernel.org>,
linux-scsi <linux-scsi@vger.kernel.org>,
linux-kernel <linux-kernel@vger.kernel.org>,
Christoph Hellwig <hch@lst.de>, Hannes Reinecke <hare@suse.de>,
Sagi Grimberg <sagig@mellanox.com>,
Or Gerlitz <ogerlitz@mellanox.com>,
Nicholas Bellinger <nab@linux-iscsi.org>
Subject: Re: [PATCH 09/14] target/configfs: Expose protection device attributes
Date: Sun, 12 Jan 2014 14:52:54 +0200 [thread overview]
Message-ID: <52D29026.6000302@dev.mellanox.co.il> (raw)
In-Reply-To: <yq138ktpdz9.fsf@sermon.lab.mkp.net>
On 1/12/2014 2:43 PM, Martin K. Petersen wrote:
>>>>>> "Sagi" == Sagi Grimberg <sagig@dev.mellanox.co.il> writes:
>>> The IP checksum is only supported by DIX between OS and initiator,
>>> not by the target. I guess we could signal to the initiator via a
>>> vendor-private VPD that IP checksum is supported directly. But now
>>> what we have hardware-accelerated T10 CRC I don't think it's a big
>>> deal.
> Sagi> shouldn't it stick around if it is not deprecated yet, the
> Sagi> transport is required to support ip-csum->CRC conversion anyhow.
>
> SBC mandates that the guard tag on the wire and on the target device be
> the T10 CRC. The IP checksum is a DIX-optimization for application-HBA
> exchanges. The only place you should support the IP checksum is in the
> initiator.
Right.
> Note that you could conceivably do a T10 CRC to IP checksum conversion
> on writes received by the target and store the IP checksum on disk. And
> then convert back to T10 CRC when the data is eventually read. But it
> makes no sense to do that given that you will have to do the T10 CRC
> calculation regardless. Even if the backing store is DIX-capable and
> supports the IP checksum.
>
I agree, but for backstore DIF (SW) emulation it will make sense.
next prev parent reply other threads:[~2014-01-12 12:52 UTC|newest]
Thread overview: 78+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-01-08 20:15 [PATCH 00/14] target: Initial support for DIF Type1+Type3 emulation Nicholas A. Bellinger
2014-01-08 20:15 ` [PATCH 01/14] target: Add DIF related base definitions Nicholas A. Bellinger
2014-01-09 10:58 ` Sagi Grimberg
2014-01-08 20:15 ` [PATCH 02/14] target: Add DIF CHECK_CONDITION ASC/ASCQ exception cases Nicholas A. Bellinger
2014-01-09 10:43 ` Sagi Grimberg
2014-01-10 6:53 ` Nicholas A. Bellinger
2014-01-14 7:44 ` Sagi Grimberg
2014-01-14 8:53 ` Nicholas A. Bellinger
2014-01-14 10:56 ` Sagi Grimberg
2014-01-08 20:15 ` [PATCH 03/14] target/sbc: Add sbc_check_prot + update sbc_parse_cdb for DIF Nicholas A. Bellinger
2014-01-09 14:58 ` Sagi Grimberg
2014-01-10 7:04 ` Nicholas A. Bellinger
2014-01-12 11:59 ` Sagi Grimberg
2014-01-13 19:23 ` Nicholas A. Bellinger
2014-01-10 20:30 ` Martin K. Petersen
2014-01-08 20:15 ` [PATCH 04/14] target/sbc: Add DIF TYPE1+TYPE3 read/write verify emulation Nicholas A. Bellinger
2014-01-08 20:15 ` [PATCH 05/14] target/spc: Add protection bit to standard INQUIRY output Nicholas A. Bellinger
2014-01-10 20:34 ` Martin K. Petersen
2014-01-08 20:15 ` [PATCH 06/14] target/spc: Add protection related bits to INQUIRY EVPD=0x86 Nicholas A. Bellinger
2014-01-10 20:35 ` Martin K. Petersen
2014-01-08 20:15 ` [PATCH 07/14] target/sbc: Add P_TYPE + PROT_EN bits to READ_CAPACITY_16 Nicholas A. Bellinger
2014-01-09 10:24 ` Sagi Grimberg
2014-01-10 6:21 ` Nicholas A. Bellinger
2014-01-10 19:50 ` Andy Grover
2014-01-10 20:15 ` Nicholas A. Bellinger
2014-01-10 20:46 ` Martin K. Petersen
2014-01-12 11:49 ` Sagi Grimberg
2014-01-10 20:40 ` Martin K. Petersen
2014-01-10 20:39 ` Martin K. Petersen
2014-01-12 12:13 ` Sagi Grimberg
2014-01-12 12:33 ` Martin K. Petersen
2014-01-12 12:47 ` Sagi Grimberg
2014-01-12 12:53 ` Martin K. Petersen
2014-01-12 16:37 ` Douglas Gilbert
2014-01-12 17:21 ` Martin K. Petersen
2014-01-12 18:53 ` Douglas Gilbert
2014-01-13 16:33 ` Sagi Grimberg
2014-01-12 12:13 ` Sagi Grimberg
2014-01-10 20:37 ` Martin K. Petersen
2014-01-08 20:15 ` [PATCH 08/14] target/spc: Expose ATO bit in control mode page Nicholas A. Bellinger
2014-01-10 20:57 ` Martin K. Petersen
2014-01-08 20:15 ` [PATCH 09/14] target/configfs: Expose protection device attributes Nicholas A. Bellinger
2014-01-09 11:01 ` Sagi Grimberg
2014-01-10 7:00 ` Nicholas A. Bellinger
2014-01-12 11:56 ` Sagi Grimberg
2014-01-10 21:01 ` Martin K. Petersen
2014-01-12 12:18 ` Sagi Grimberg
2014-01-12 12:43 ` Martin K. Petersen
2014-01-12 12:52 ` Sagi Grimberg [this message]
2014-01-13 18:30 ` Nicholas A. Bellinger
2014-01-13 18:52 ` James Bottomley
2014-01-13 19:27 ` Nicholas A. Bellinger
2014-01-13 19:43 ` James Bottomley
2014-01-13 20:19 ` Martin K. Petersen
2014-01-13 20:24 ` James Bottomley
2014-01-13 20:30 ` Martin K. Petersen
2014-01-08 20:15 ` [PATCH 10/14] target: Add protection SGLs to target_submit_cmd_map_sgls Nicholas A. Bellinger
2014-01-08 20:15 ` [PATCH 11/14] target/rd: Refactor rd_build_device_space + rd_release_device_space Nicholas A. Bellinger
2014-01-08 20:15 ` [PATCH 12/14] target/rd: Add support for protection SGL setup + release Nicholas A. Bellinger
2014-01-08 20:15 ` [PATCH 13/14] target/rd: Add DIF protection into rd_execute_rw Nicholas A. Bellinger
2014-01-09 10:32 ` Sagi Grimberg
2014-01-10 6:52 ` Nicholas A. Bellinger
2014-01-12 11:53 ` Sagi Grimberg
2014-01-13 19:22 ` Nicholas A. Bellinger
2014-01-10 21:06 ` Martin K. Petersen
2014-01-12 12:23 ` Sagi Grimberg
2014-01-08 20:15 ` [PATCH 14/14] tcm_loop: Enable DIF/DIX modes in SCSI host LLD Nicholas A. Bellinger
2014-01-10 21:09 ` Martin K. Petersen
2014-01-13 18:45 ` Nicholas A. Bellinger
2014-01-13 20:08 ` Martin K. Petersen
2014-01-10 2:00 ` [PATCH 00/14] target: Initial support for DIF Type1+Type3 emulation Martin K. Petersen
2014-01-10 5:57 ` Nicholas A. Bellinger
2014-01-15 18:03 ` sagi grimberg
2014-01-15 21:55 ` Nicholas A. Bellinger
2014-01-16 1:42 ` Martin K. Petersen
2014-01-16 2:32 ` Nicholas A. Bellinger
2014-01-16 3:04 ` Martin K. Petersen
2014-01-16 7:45 ` sagi grimberg
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