From: "Javier González" <javier.gonz@samsung.com>
To: Christoph Hellwig <hch@lst.de>
Cc: Minwoo Im <minwoo.im.dev@gmail.com>,
<linux-nvme@lists.infradead.org>, Keith Busch <kbusch@kernel.org>,
Jens Axboe <axboe@fb.com>, Sagi Grimberg <sagi@grimberg.me>,
Kanchan Joshi <joshiiitr@gmail.com>
Subject: Re: [PATCH V2 1/1] nvme: introduce generic per-namespace chardev
Date: Thu, 8 Apr 2021 12:26:25 +0200 [thread overview]
Message-ID: <20210408102625.2u6sarhs2qss35ft@mpHalley.local> (raw)
In-Reply-To: <20210408072641.GA24793@lst.de>
On 08.04.2021 09:26, Christoph Hellwig wrote:
>On Thu, Apr 08, 2021 at 09:11:28AM +0200, Javier González wrote:
>> This would be useful for devices with metadata that is not supported by
>> the block layer, i.e., nvme_configure_metadata().
>
>You mean in nvme_update_disk_info? It would be the right thing to do,
>but back in the day the maintainers opted for the zero capacity
>block device hack. At least we now have the char device as well.
Yes. This path starts in nvme_update_ns_info() and part of it is
nvme_configure_metadata(), which might fail is the metadata is not
supported.
In this case, I believe we should still create the char device so that
any OME-specific NVMe device can still be used from user-space without
requiring SPDK and a PCI detach.
Does this sound good to you?
Regarding the current logic, I would not mind that the block device
still appears as a zero capacity too. We can think of removing this in
the future as this path becomes more stable. It requeries Kanchan's work
on io_uring to be usable for I/O.
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next prev parent reply other threads:[~2021-04-08 10:26 UTC|newest]
Thread overview: 31+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-04-06 6:48 [PATCH V2 0/1] nvme: introduce generic per-namespace chardev Minwoo Im
2021-04-06 6:48 ` [PATCH V2 1/1] " Minwoo Im
2021-04-07 13:15 ` Christoph Hellwig
2021-04-07 14:11 ` Minwoo Im
2021-04-07 14:21 ` Christoph Hellwig
2021-04-07 15:35 ` Minwoo Im
2021-04-07 15:40 ` Christoph Hellwig
2021-04-07 15:44 ` Minwoo Im
2021-04-07 15:47 ` Minwoo Im
2021-04-07 16:48 ` Christoph Hellwig
2021-04-07 16:59 ` Minwoo Im
2021-04-07 17:09 ` Minwoo Im
2021-04-07 17:14 ` Christoph Hellwig
2021-04-08 7:11 ` Javier González
2021-04-08 7:26 ` Christoph Hellwig
2021-04-08 10:26 ` Javier González [this message]
2021-04-08 11:27 ` Christoph Hellwig
2021-04-08 11:46 ` Javier González
2021-04-08 12:41 ` Minwoo Im
2021-04-06 9:01 ` [PATCH V2 0/1] " Niklas Cassel
2021-04-06 13:35 ` Minwoo Im
2021-04-06 14:59 ` Christoph Hellwig
2021-04-06 16:23 ` Minwoo Im
2021-04-07 6:00 ` Christoph Hellwig
2021-04-07 6:02 ` Minwoo Im
2021-04-07 7:36 ` Niklas Cassel
2021-04-07 9:39 ` Christoph Hellwig
2021-04-07 10:00 ` Niklas Cassel
2021-04-07 10:34 ` Damien Le Moal
2021-04-07 11:50 ` Javier González
2021-04-06 14:13 ` Kanchan Joshi
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