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 12:12:35 +0200 [thread overview]
Message-ID: <20220713101235.GA27815@lst.de> (raw)
In-Reply-To: <24f0a3e6-aa53-8c69-71b7-d66289a63eae@grimberg.me>
On Wed, Jul 13, 2022 at 11:04:31AM +0300, Sagi Grimberg wrote:
> Maybe the solution is to just not expose a /dev/ng for the mpath device
> node, but only for bottom namespaces. Then it would be completely
> equivalent to scsi-generic devices.
>
> It just creates an unexpected mix of semantics of best-effort
> multipathing with just path selection, but no requeue/failover...
Which is exactly the same semanics as SG_IO on the dm-mpath nodes.
> If the user needs to do the retry, discover and understand namespace
> paths, ANA states, controller states, etc. Why does the user need a
> mpath chardev at all?
The user needs to do that for all kinds of other resons anyway,
as we don't do any retries for passthrough at all.
next prev parent reply other threads:[~2022-07-13 10:13 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
2022-07-13 8:04 ` Sagi Grimberg
2022-07-13 10:12 ` Christoph Hellwig [this message]
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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