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From: Christoph Hellwig <hch@lst.de>
To: Keith Busch <kbusch@kernel.org>
Cc: "Javier González" <javier@javigon.com>,
	"Minwoo Im" <minwoo.im.dev@gmail.com>,
	linux-nvme@lists.infradead.org, linux-block@vger.kernel.org,
	hch@lst.de, sagi@grimberg.me
Subject: Re: [PATCH 4/4] nvme: enable char device per namespace
Date: Tue, 1 Dec 2020 20:38:23 +0100	[thread overview]
Message-ID: <20201201193823.GA3522@lst.de> (raw)
In-Reply-To: <20201201193002.GB27728@redsun51.ssa.fujisawa.hgst.com>

On Wed, Dec 02, 2020 at 04:30:02AM +0900, Keith Busch wrote:
> > > In multi-path, private namespaces for a head are not in /dev, so I don't
> > > think this will hurt private namespaces (e.g., nvme0c0n1), But it looks
> > > like it will make a little bit confusions between chardev and hidden blkdev.
> > > 
> > > I don't against to update nvme-cli things also even naming conventions are
> > > going to become different than nvmeXcYnZ.
> > 
> > Agree. But as I understand it, Keith had a good argument to keep names
> > aligned with the hidden bdev. 
> 
> My suggested naming makes it as obvious as possible that the character
> device in /dev/ and the hidden block device in /sys/ are referring to
> the same thing. What is confusing about that?
> 
> > It is also true that in that comment he suggested nesting the char
> > device in /dev/nvme
> 
> Yeah, I'm okay with sub-directories for these special handles, but there
> are arguments against it too. I don't feel that strongly about it either
> way.

I'd prefer different naming for the char vs the block devices.  Yes,
this will require a little work in the userspace tools to support the
character device, but I think it is much cleaner.

Devices in subdirectories of /dev/ are very rare and keep causing problem
with userspace tooling for the few drivers that use them, so I don't
think they are a good idea.

WARNING: multiple messages have this Message-ID (diff)
From: Christoph Hellwig <hch@lst.de>
To: Keith Busch <kbusch@kernel.org>
Cc: "Javier González" <javier@javigon.com>,
	sagi@grimberg.me, linux-nvme@lists.infradead.org,
	linux-block@vger.kernel.org,
	"Minwoo Im" <minwoo.im.dev@gmail.com>,
	hch@lst.de
Subject: Re: [PATCH 4/4] nvme: enable char device per namespace
Date: Tue, 1 Dec 2020 20:38:23 +0100	[thread overview]
Message-ID: <20201201193823.GA3522@lst.de> (raw)
In-Reply-To: <20201201193002.GB27728@redsun51.ssa.fujisawa.hgst.com>

On Wed, Dec 02, 2020 at 04:30:02AM +0900, Keith Busch wrote:
> > > In multi-path, private namespaces for a head are not in /dev, so I don't
> > > think this will hurt private namespaces (e.g., nvme0c0n1), But it looks
> > > like it will make a little bit confusions between chardev and hidden blkdev.
> > > 
> > > I don't against to update nvme-cli things also even naming conventions are
> > > going to become different than nvmeXcYnZ.
> > 
> > Agree. But as I understand it, Keith had a good argument to keep names
> > aligned with the hidden bdev. 
> 
> My suggested naming makes it as obvious as possible that the character
> device in /dev/ and the hidden block device in /sys/ are referring to
> the same thing. What is confusing about that?
> 
> > It is also true that in that comment he suggested nesting the char
> > device in /dev/nvme
> 
> Yeah, I'm okay with sub-directories for these special handles, but there
> are arguments against it too. I don't feel that strongly about it either
> way.

I'd prefer different naming for the char vs the block devices.  Yes,
this will require a little work in the userspace tools to support the
character device, but I think it is much cleaner.

Devices in subdirectories of /dev/ are very rare and keep causing problem
with userspace tooling for the few drivers that use them, so I don't
think they are a good idea.

_______________________________________________
Linux-nvme mailing list
Linux-nvme@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-nvme

  reply	other threads:[~2020-12-01 19:39 UTC|newest]

Thread overview: 32+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-12-01 12:56 [PATCH 0/4] nvme: enable per-namespace char device javier
2020-12-01 12:56 ` javier
2020-12-01 12:56 ` [PATCH 1/4] nvme: remove unnecessary return values javier
2020-12-01 12:56   ` javier
2020-12-01 14:04   ` Minwoo Im
2020-12-01 14:04     ` Minwoo Im
2020-12-01 12:56 ` [PATCH 2/4] nvme: rename controller base dev_t char device javier
2020-12-01 12:56   ` javier
2020-12-01 14:05   ` Minwoo Im
2020-12-01 14:05     ` Minwoo Im
2020-12-01 12:56 ` [PATCH 3/4] nvme: rename bdev operations javier
2020-12-01 12:56   ` javier
2020-12-01 14:06   ` Minwoo Im
2020-12-01 14:06     ` Minwoo Im
2020-12-01 12:56 ` [PATCH 4/4] nvme: enable char device per namespace javier
2020-12-01 12:56   ` javier
2020-12-01 14:03   ` Minwoo Im
2020-12-01 14:03     ` Minwoo Im
2020-12-01 18:57     ` Javier González
2020-12-01 18:57       ` Javier González
2020-12-01 19:30       ` Keith Busch
2020-12-01 19:30         ` Keith Busch
2020-12-01 19:38         ` Christoph Hellwig [this message]
2020-12-01 19:38           ` Christoph Hellwig
2020-12-01 20:44           ` Javier González
2020-12-01 20:44             ` Javier González
2020-12-07 14:06             ` Christoph Hellwig
2020-12-07 14:06               ` Christoph Hellwig
2020-12-02  3:00         ` Minwoo Im
2020-12-02  3:00           ` Minwoo Im
2020-12-01 19:35 ` [PATCH 0/4] nvme: enable per-namespace char device Christoph Hellwig
2020-12-01 19:35   ` Christoph Hellwig

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