All of lore.kernel.org
 help / color / mirror / Atom feed
From: Mike Snitzer <snitzer@redhat.com>
To: Christoph Hellwig <hch@lst.de>
Cc: Hannes Reinecke <hare@suse.de>,
	Keith Busch <keith.busch@intel.com>,
	"Martin K. Petersen" <martin.petersen@oracle.com>,
	"linux-scsi@vger.kernel.org" <linux-scsi@vger.kernel.org>,
	Bart van Assche <bart.vanassche@sandisk.com>,
	Hannes Reinecke <hare@suse.com>,
	device-mapper development <dm-devel@redhat.com>,
	linux-block@vger.kernel.org
Subject: Re: [PATCHv2] scsi: use 'scsi_device_from_queue()' for scsi_dh
Date: Sun, 19 Feb 2017 00:59:06 -0500	[thread overview]
Message-ID: <CAMM=eLfpNCxj4yegh3vNGYawh0X+-ya3ZHjoPC9ogRKGa8azFw@mail.gmail.com> (raw)
In-Reply-To: <20170217082752.GA18258@lst.de>

On Fri, Feb 17, 2017 at 3:27 AM, Christoph Hellwig <hch@lst.de> wrote:
>
> On Fri, Feb 17, 2017 at 09:06:14AM +0100, Hannes Reinecke wrote:
> > We could, but why?
> > ATM we're only having SCSI devices able to use device handler; adding
> > another layer of indirection doesn't solve anything here.
> > Moving the infrastructure one level up will only make sense if we're
> > getting non-SCSI device handler (ANA?), but until then I'd think it's
> > just overengineering.
>
> Agreed.  Independent of what does the balancing between queues hardware
> handler should be attached by the low-level driver for any future
> transport without any control from DM.

But doesn't Keith's abstraction makes a lot of sense given that you're
providing a device handler interface for NVMe?

The most important part of scsi_dh that DM uses is its calls to
scsi_dh_activate.  Attachment isn't interesting or the issue (DM's
call to scsi_dh_attach is purely legacy now that SCSI attaches the
proper scsi_dh during SCSI's device scan).

WARNING: multiple messages have this Message-ID (diff)
From: Mike Snitzer <snitzer@redhat.com>
To: Christoph Hellwig <hch@lst.de>
Cc: linux-block@vger.kernel.org, Hannes Reinecke <hare@suse.com>,
	"linux-scsi@vger.kernel.org" <linux-scsi@vger.kernel.org>,
	"Martin K. Petersen" <martin.petersen@oracle.com>,
	Keith Busch <keith.busch@intel.com>,
	device-mapper development <dm-devel@redhat.com>,
	Bart van Assche <bart.vanassche@sandisk.com>
Subject: Re: [PATCHv2] scsi: use 'scsi_device_from_queue()' for scsi_dh
Date: Sun, 19 Feb 2017 00:59:06 -0500	[thread overview]
Message-ID: <CAMM=eLfpNCxj4yegh3vNGYawh0X+-ya3ZHjoPC9ogRKGa8azFw@mail.gmail.com> (raw)
In-Reply-To: <20170217082752.GA18258@lst.de>

On Fri, Feb 17, 2017 at 3:27 AM, Christoph Hellwig <hch@lst.de> wrote:
>
> On Fri, Feb 17, 2017 at 09:06:14AM +0100, Hannes Reinecke wrote:
> > We could, but why?
> > ATM we're only having SCSI devices able to use device handler; adding
> > another layer of indirection doesn't solve anything here.
> > Moving the infrastructure one level up will only make sense if we're
> > getting non-SCSI device handler (ANA?), but until then I'd think it's
> > just overengineering.
>
> Agreed.  Independent of what does the balancing between queues hardware
> handler should be attached by the low-level driver for any future
> transport without any control from DM.

But doesn't Keith's abstraction makes a lot of sense given that you're
providing a device handler interface for NVMe?

The most important part of scsi_dh that DM uses is its calls to
scsi_dh_activate.  Attachment isn't interesting or the issue (DM's
call to scsi_dh_attach is purely legacy now that SCSI attaches the
proper scsi_dh during SCSI's device scan).

  reply	other threads:[~2017-02-19  6:05 UTC|newest]

Thread overview: 9+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2017-02-16 15:12 [PATCHv2] scsi: use 'scsi_device_from_queue()' for scsi_dh Hannes Reinecke
2017-02-16 16:09 ` Bart Van Assche
2017-02-17  7:19   ` Hannes Reinecke
2017-02-16 17:05 ` Keith Busch
2017-02-16 17:13   ` Keith Busch
2017-02-17  8:06   ` Hannes Reinecke
2017-02-17  8:27     ` Christoph Hellwig
2017-02-19  5:59       ` Mike Snitzer [this message]
2017-02-19  5:59         ` Mike Snitzer

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to='CAMM=eLfpNCxj4yegh3vNGYawh0X+-ya3ZHjoPC9ogRKGa8azFw@mail.gmail.com' \
    --to=snitzer@redhat.com \
    --cc=bart.vanassche@sandisk.com \
    --cc=dm-devel@redhat.com \
    --cc=hare@suse.com \
    --cc=hare@suse.de \
    --cc=hch@lst.de \
    --cc=keith.busch@intel.com \
    --cc=linux-block@vger.kernel.org \
    --cc=linux-scsi@vger.kernel.org \
    --cc=martin.petersen@oracle.com \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body. 
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.