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Subject: Re: [PATCH v7 08/14] nvmet-core: allow one host per passthru-ctrl
To:     Max Gurtovoy <maxg@mellanox.com>,
        Logan Gunthorpe <logang@deltatee.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>
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 <5717f515-e051-c420-07b7-299bcfcd1f32@mellanox.com>
From:   Sagi Grimberg <sagi@grimberg.me>
Message-ID: <b0921c72-93f1-f67a-c4b3-31baeb1c39cb@grimberg.me>
Date:   Wed, 21 Aug 2019 17:09:23 -0700
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> 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)