From: Logan Gunthorpe <logang@deltatee.com>
To: Sagi Grimberg <sagi@grimberg.me>,
Max Gurtovoy <maxg@mellanox.com>,
linux-kernel@vger.kernel.org, linux-nvme@lists.infradead.org,
linux-block@vger.kernel.org, linux-fsdevel@vger.kernel.org
Cc: Chaitanya Kulkarni <Chaitanya.Kulkarni@wdc.com>,
Stephen Bates <sbates@raithlin.com>, Jens Axboe <axboe@fb.com>,
Keith Busch <kbusch@kernel.org>, Christoph Hellwig <hch@lst.de>
Subject: Re: [PATCH v7 08/14] nvmet-core: allow one host per passthru-ctrl
Date: Thu, 22 Aug 2019 13:41:32 -0600 [thread overview]
Message-ID: <5e53b732-5c33-c331-0c77-d52d5075306a@deltatee.com> (raw)
In-Reply-To: <e4430207-7def-8776-0289-0d58689dc0cd@grimberg.me>
On 2019-08-22 1:17 p.m., Sagi Grimberg wrote:
>
>>>>> I don't understand why we don't limit a regular ctrl to single
>>>>> access and we do it for the PT ctrl.
>>>>>
>>>>> I guess the block layer helps to sync between multiple access in
>>>>> parallel but we can do it as well.
>>>>>
>>>>> Also, let's say you limit the access to this subsystem to 1 user,
>>>>> the bdev is still accessibly for local user and also you can create
>>>>> a different subsystem that will use this device (PT and non-PT ctrl).
>>>>>
>>>>> Sagi,
>>>>>
>>>>> can you explain the trouble you meant and how this limitation solve
>>>>> it ?
>>>>
>>>> Its different to emulate the controller with all its admin
>>>> commands vs. passing it through to the nvme device.. (think of
>>>> format nvm)
>>>>
>>>>
>>>>
>>> we don't need to support format command for PT ctrl as we don't
>>> support other commands such create_sq/cq.
>>
>> That is just an example, basically every command that we are not aware
>> of we simply passthru to the drive without knowing the implications
>> on a multi-host environment..
>
> If we were to change the logic of nvmet_parse_passthru_admin_cmd to
> have the default case do nvmet_parse_admin_cmd, and only have
> the vendor-specific space opcodes do nvmet_passthru_execute_cmd
> then I could not see at the moment how we can break a multi-host
> export...
That makes sense. I'll make that change and resend a v8 next week.
Logan
next prev parent reply other threads:[~2019-08-22 19:41 UTC|newest]
Thread overview: 62+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-08-01 23:44 [PATCH v7 00/14] nvmet: add target passthru commands support Logan Gunthorpe
2019-08-01 23:44 ` Logan Gunthorpe
2019-08-01 23:45 ` [PATCH v7 01/14] nvme-core: introduce nvme_ctrl_get_by_path() Logan Gunthorpe
2019-08-01 23:45 ` Logan Gunthorpe
2019-08-14 14:20 ` Max Gurtovoy
2019-08-14 14:20 ` Max Gurtovoy
2019-08-15 11:46 ` Max Gurtovoy
2019-08-15 11:46 ` Max Gurtovoy
2019-08-15 15:59 ` Logan Gunthorpe
2019-08-15 15:59 ` Logan Gunthorpe
2019-08-01 23:45 ` [PATCH v7 02/14] nvme-core: export existing ctrl and ns interfaces Logan Gunthorpe
2019-08-01 23:45 ` Logan Gunthorpe
2019-08-01 23:45 ` [PATCH v7 03/14] nvmet: add return value to nvmet_add_async_event() Logan Gunthorpe
2019-08-01 23:45 ` Logan Gunthorpe
2019-08-14 14:26 ` Max Gurtovoy
2019-08-14 14:26 ` Max Gurtovoy
2019-08-14 16:59 ` Logan Gunthorpe
2019-08-14 16:59 ` Logan Gunthorpe
2019-08-01 23:45 ` [PATCH v7 04/14] nvmet: make nvmet_copy_ns_identifier() non-static Logan Gunthorpe
2019-08-01 23:45 ` Logan Gunthorpe
2019-08-14 14:29 ` Max Gurtovoy
2019-08-14 14:29 ` Max Gurtovoy
2019-08-15 7:15 ` Chaitanya Kulkarni
2019-08-15 7:15 ` Chaitanya Kulkarni
2019-08-01 23:45 ` [PATCH v7 05/14] nvmet-passthru: update KConfig with config passthru option Logan Gunthorpe
2019-08-01 23:45 ` Logan Gunthorpe
2019-08-14 14:31 ` Max Gurtovoy
2019-08-14 14:31 ` Max Gurtovoy
2019-08-01 23:45 ` [PATCH v7 06/14] nvmet-passthru: add passthru code to process commands Logan Gunthorpe
2019-08-01 23:45 ` Logan Gunthorpe
2019-08-01 23:45 ` [PATCH v7 07/14] nvmet-passthru: add enable/disable helpers Logan Gunthorpe
2019-08-01 23:45 ` Logan Gunthorpe
2019-08-15 12:20 ` Max Gurtovoy
2019-08-15 12:20 ` Max Gurtovoy
2019-08-15 16:02 ` Logan Gunthorpe
2019-08-15 16:02 ` Logan Gunthorpe
2019-08-01 23:45 ` [PATCH v7 08/14] nvmet-core: allow one host per passthru-ctrl Logan Gunthorpe
2019-08-01 23:45 ` Logan Gunthorpe
2019-08-15 12:36 ` Max Gurtovoy
2019-08-15 12:36 ` Max Gurtovoy
2019-08-15 16:06 ` Logan Gunthorpe
2019-08-15 16:06 ` Logan Gunthorpe
2019-08-18 10:33 ` Max Gurtovoy
2019-08-22 0:09 ` Sagi Grimberg
2019-08-22 8:50 ` Max Gurtovoy
2019-08-22 17:41 ` Sagi Grimberg
2019-08-22 19:17 ` Sagi Grimberg
2019-08-22 19:41 ` Logan Gunthorpe [this message]
2019-08-01 23:45 ` [PATCH v7 09/14] nvmet-core: don't check the data len for pt-ctrl Logan Gunthorpe
2019-08-01 23:45 ` Logan Gunthorpe
2019-08-01 23:45 ` [PATCH v7 10/14] nvmet-tcp: don't check data_len in nvmet_tcp_map_data() Logan Gunthorpe
2019-08-01 23:45 ` Logan Gunthorpe
2019-08-01 23:45 ` [PATCH v7 11/14] nvmet-configfs: introduce passthru configfs interface Logan Gunthorpe
2019-08-01 23:45 ` Logan Gunthorpe
2019-08-15 12:46 ` Max Gurtovoy
2019-08-15 12:46 ` Max Gurtovoy
2019-08-01 23:45 ` [PATCH v7 12/14] block: don't check blk_rq_is_passthrough() in blk_do_io_stat() Logan Gunthorpe
2019-08-01 23:45 ` Logan Gunthorpe
2019-08-01 23:45 ` [PATCH v7 13/14] block: call blk_account_io_start() in blk_execute_rq_nowait() Logan Gunthorpe
2019-08-01 23:45 ` Logan Gunthorpe
2019-08-01 23:45 ` [PATCH v7 14/14] nvmet-passthru: support block accounting Logan Gunthorpe
2019-08-01 23:45 ` Logan Gunthorpe
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