From: "Martin K. Petersen" <martin.petersen@oracle.com>
To: Max Gurtovoy <maxg@mellanox.com>
Cc: sagi@grimberg.me, vladimirk@mellanox.com, idanb@mellanox.com,
israelr@mellanox.com, linux-nvme@lists.infradead.org,
shlomin@mellanox.com, oren@mellanox.com,
"Martin K. Petersen" <martin.petersen@oracle.com>,
kbusch@kernel.org, hch@lst.de
Subject: Re: [PATCH 06/15] block: Introduce BIP_NOMAP_INTEGRITY bip_flag
Date: Fri, 08 Nov 2019 21:10:26 -0500 [thread overview]
Message-ID: <yq1zhh5vlyl.fsf@oracle.com> (raw)
In-Reply-To: <578955b0-719e-0ab4-919f-b4ec84d1f77d@mellanox.com> (Max Gurtovoy's message of "Thu, 7 Nov 2019 15:29:25 +0200")
Max,
> In the fabric solution the Initiator side is the SW controller of the
> namespace and the target is kinda HW controller.
>
> The SW controller is doing the reftag remapping during
> prepare/complete functions and it should be done only once.
>
> The HW controller should write/read the data from the media as is (and
> maybe verify/add it).
>
> When you're using an NVMe disk as the bdev for the target namespace,
> then prepare/complete will be called also in the "target" side and we
> don't want double remapping to happen.
In a typical SCSI setup you'll have remapping several times as the file
block offset visible to an application is different from the LBA on the
LUN. And the LUN LBA is different from the LBA of the drive physically
storing the data block inside the disk array.
To me it sounds like your 1:1 mapping between host LBA and target
back-end LBA is just a special case. What happens in your scenario if
the target bdev is a partition and not a full namespace?
> In the complete_fn there is no option to skip the remapping...
Only because there hasn't been a need. Feel free to add a
BIP_MAPPED_INTEGRITY check to complete_fn.
--
Martin K. Petersen Oracle Linux Engineering
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next prev parent reply other threads:[~2019-11-09 2:10 UTC|newest]
Thread overview: 52+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-11-05 16:20 [PATCH 00/15] nvme-rdma/nvmet-rdma: Add metadata/T10-PI support Max Gurtovoy
2019-11-05 16:20 ` [PATCH] nvme-cli/fabrics: Add pi_enable param to connect cmd Max Gurtovoy
2019-11-07 2:36 ` Martin K. Petersen
2019-11-07 12:02 ` Max Gurtovoy
2019-11-09 1:55 ` Martin K. Petersen
2019-11-10 9:25 ` Max Gurtovoy
2019-11-12 17:47 ` Sagi Grimberg
2019-11-12 18:14 ` James Smart
2019-11-12 18:23 ` Sagi Grimberg
2019-11-05 16:20 ` [PATCH 01/15] nvme-fabrics: allow user enabling metadata/T10-PI support Max Gurtovoy
2019-11-12 17:48 ` Sagi Grimberg
2019-11-05 16:20 ` [PATCH 02/15] nvme: Fail __nvme_revalidate_disk in case of a spec violation Max Gurtovoy
2019-11-05 17:49 ` Christoph Hellwig
2019-11-12 17:52 ` Sagi Grimberg
2019-11-05 16:20 ` [PATCH 03/15] nvme: Introduce max_integrity_segments ctrl attribute Max Gurtovoy
2019-11-05 17:49 ` Christoph Hellwig
2019-11-12 17:53 ` Sagi Grimberg
2019-11-05 16:20 ` [PATCH 04/15] nvme: Inline nvme_ns_has_pi function Max Gurtovoy
2019-11-05 17:50 ` Christoph Hellwig
2019-11-05 16:20 ` [PATCH 05/15] nvme-rdma: Add metadata/T10-PI support Max Gurtovoy
2019-11-05 17:58 ` Christoph Hellwig
2019-11-20 10:41 ` Max Gurtovoy
2019-11-12 18:22 ` Sagi Grimberg
2019-11-13 14:35 ` Max Gurtovoy
2019-11-14 23:57 ` Sagi Grimberg
2019-11-05 16:20 ` [PATCH 06/15] block: Introduce BIP_NOMAP_INTEGRITY bip_flag Max Gurtovoy
2019-11-05 17:52 ` Christoph Hellwig
2019-11-07 2:43 ` Martin K. Petersen
2019-11-07 13:29 ` Max Gurtovoy
2019-11-09 2:10 ` Martin K. Petersen [this message]
2019-11-12 10:40 ` Max Gurtovoy
2019-11-05 16:20 ` [PATCH 07/15] nvmet: Prepare metadata request Max Gurtovoy
2019-11-05 16:20 ` [PATCH 08/15] nvmet: Add metadata characteristics for a namespace Max Gurtovoy
2019-11-05 17:59 ` Christoph Hellwig
2019-11-12 18:38 ` Sagi Grimberg
2019-11-05 16:20 ` [PATCH 09/15] nvmet: Rename nvmet_rw_len to nvmet_rw_data_len Max Gurtovoy
2019-11-05 17:59 ` Christoph Hellwig
2019-11-12 18:39 ` Sagi Grimberg
2019-11-05 16:20 ` [PATCH 10/15] nvmet: Rename nvmet_check_data_len to nvmet_check_transfer_len Max Gurtovoy
2019-11-05 18:00 ` Christoph Hellwig
2019-11-12 18:43 ` Sagi Grimberg
2019-11-05 16:20 ` [PATCH 11/15] nvmet: Introduce nvmet_rw_prot_len and nvmet_ns_has_pi Max Gurtovoy
2019-11-05 18:00 ` Christoph Hellwig
2019-11-05 16:20 ` [PATCH 12/15] nvme: Add Metadata Capabilities enumerations Max Gurtovoy
2019-11-05 16:20 ` [PATCH 13/15] nvmet: Add metadata/T10-PI support Max Gurtovoy
2019-11-05 16:20 ` [PATCH 14/15] nvmet: Add metadata support for block devices Max Gurtovoy
2019-11-05 16:20 ` [PATCH 15/15] nvmet-rdma: Add metadata/T10-PI support Max Gurtovoy
2019-11-05 18:02 ` Christoph Hellwig
2019-11-07 13:43 ` Max Gurtovoy
2019-11-12 18:34 ` Sagi Grimberg
2019-11-13 13:56 ` Max Gurtovoy
2019-11-14 23:45 ` Sagi Grimberg
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