From: Christoph Hellwig <hch@lst.de>
To: Sagi Grimberg <sagi@grimberg.me>
Cc: Christoph Hellwig <hch@lst.de>,
Kanchan Joshi <joshi.k@samsung.com>,
kbusch@kernel.org, axboe@kernel.dk, io-uring@vger.kernel.org,
linux-nvme@lists.infradead.org, linux-block@vger.kernel.org,
asml.silence@gmail.com, joshiiitr@gmail.com,
anuj20.g@samsung.com, gost.dev@samsung.com
Subject: Re: [PATCH for-next 4/4] nvme-multipath: add multipathing for uring-passthrough commands
Date: Wed, 13 Jul 2022 07:36:33 +0200 [thread overview]
Message-ID: <20220713053633.GA13135@lst.de> (raw)
In-Reply-To: <436c8875-5a99-4328-80ac-6a5aef7f16f4@grimberg.me>
On Tue, Jul 12, 2022 at 11:13:57PM +0300, Sagi Grimberg wrote:
> I think the difference from scsi-generic and controller nvme passthru is
> that this is a mpath device node (or mpath chardev). This is why I think
> that users would expect that it would have equivalent multipath
> capabilities (i.e. failover).
How is that different from /dev/sg?
> In general, I think that uring passthru as an alternative I/O interface
> and as such needs to be able to failover. If this is not expected from
> the interface, then why are we exposing a chardev for the mpath device
> node? why not only the bottom namespaces?
The failover will happen when you retry, but we leave that retry to
userspace. There even is the uevent to tell userspace when a new
path is up.
next prev parent reply other threads:[~2022-07-13 5:41 UTC|newest]
Thread overview: 52+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <CGME20220711110753epcas5p4169b9e288d15ca35740dbb66a6f6983a@epcas5p4.samsung.com>
2022-07-11 11:01 ` [PATCH for-next 0/4] nvme-multipathing for uring-passthrough Kanchan Joshi
2022-07-11 11:01 ` [PATCH for-next 1/4] io_uring, nvme: rename a function Kanchan Joshi
2022-07-14 13:55 ` Ming Lei
2022-07-11 11:01 ` [PATCH for-next 2/4] nvme: compact nvme_uring_cmd_pdu struct Kanchan Joshi
2022-07-12 6:32 ` Christoph Hellwig
2022-07-11 11:01 ` [PATCH for-next 3/4] io_uring: grow a field in struct io_uring_cmd Kanchan Joshi
2022-07-11 17:00 ` Sagi Grimberg
2022-07-11 17:19 ` Jens Axboe
2022-07-11 17:18 ` Jens Axboe
2022-07-11 17:55 ` Sagi Grimberg
2022-07-11 18:22 ` Sagi Grimberg
2022-07-11 18:24 ` Jens Axboe
2022-07-11 18:58 ` Sagi Grimberg
2022-07-12 11:40 ` Kanchan Joshi
2022-07-14 3:40 ` Ming Lei
2022-07-14 8:19 ` Kanchan Joshi
2022-07-14 15:30 ` Daniel Wagner
2022-07-15 11:07 ` Kanchan Joshi
2022-07-18 9:03 ` Daniel Wagner
2022-07-11 11:01 ` [PATCH for-next 4/4] nvme-multipath: add multipathing for uring-passthrough commands Kanchan Joshi
2022-07-11 13:51 ` Sagi Grimberg
2022-07-11 15:12 ` Stefan Metzmacher
2022-07-11 16:58 ` Sagi Grimberg
2022-07-11 18:54 ` Kanchan Joshi
2022-07-11 18:37 ` Kanchan Joshi
2022-07-11 19:56 ` Sagi Grimberg
2022-07-12 4:23 ` Kanchan Joshi
2022-07-12 21:26 ` Sagi Grimberg
2022-07-13 5:37 ` Kanchan Joshi
2022-07-13 9:03 ` Sagi Grimberg
2022-07-13 11:28 ` Kanchan Joshi
2022-07-13 12:17 ` Sagi Grimberg
2022-07-14 15:14 ` Ming Lei
2022-07-14 23:05 ` Kanchan Joshi
2022-07-15 1:35 ` Ming Lei
2022-07-15 1:46 ` Ming Lei
2022-07-15 4:24 ` Kanchan Joshi
2022-07-12 6:52 ` Christoph Hellwig
2022-07-12 11:33 ` Kanchan Joshi
2022-07-12 20:13 ` Sagi Grimberg
2022-07-13 5:36 ` Christoph Hellwig [this message]
2022-07-13 8:04 ` Sagi Grimberg
2022-07-13 10:12 ` Christoph Hellwig
2022-07-13 11:00 ` Sagi Grimberg
2022-07-13 11:28 ` Christoph Hellwig
2022-07-13 12:16 ` Sagi Grimberg
2022-07-13 11:49 ` Hannes Reinecke
2022-07-13 12:43 ` Sagi Grimberg
2022-07-13 13:30 ` Hannes Reinecke
2022-07-13 13:41 ` Sagi Grimberg
2022-07-13 14:07 ` Hannes Reinecke
2022-07-13 15:59 ` Sagi Grimberg
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