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From: Christoph Hellwig <[email protected]>
To: Sagi Grimberg <[email protected]>
Cc: Christoph Hellwig <[email protected]>,
	Kanchan Joshi <[email protected]>,
	[email protected], [email protected], [email protected],
	[email protected], [email protected],
	[email protected], [email protected],
	[email protected], [email protected]
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: <[email protected]> (raw)
In-Reply-To: <[email protected]>

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.

  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
     [not found]   ` <CGME20220711110800epcas5p3d338dd486fd778c5ba5bfe93a91ec8bd@epcas5p3.samsung.com>
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
     [not found]   ` <CGME20220711110812epcas5p33aa90b23aa62fb11722aa8195754becf@epcas5p3.samsung.com>
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
     [not found]   ` <CGME20220711110824epcas5p22c8e945cb8c3c3ac46c8c2b5ab55db9b@epcas5p2.samsung.com>
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
     [not found]   ` <CGME20220711110827epcas5p3fd81f142f55ca3048abc38a9ef0d0089@epcas5p3.samsung.com>
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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