Re: [PATCH 4/4] virtio_blk: use disk_name_format() to support mass of disks naming

From: "Michael S. Tsirkin" <mst@redhat.com>
To: Ren Mingxin <renmx@cn.fujitsu.com>
Cc: Tejun Heo <tj@kernel.org>,
	James Bottomley <James.Bottomley@HansenPartnership.com>,
	Jens Axboe <axboe@kernel.dk>, KVM <kvm@vger.kernel.org>,
	SCSI <linux-scsi@vger.kernel.org>,
	LKML <linux-kernel@vger.kernel.org>,
	VIRTUAL <virtualization@lists.linux-foundation.org>
Subject: Re: [PATCH 4/4] virtio_blk: use disk_name_format() to support mass of disks naming
Date: Mon, 9 Apr 2012 10:50:01 +0300	[thread overview]
Message-ID: <20120409075001.GA27771@redhat.com> (raw)
In-Reply-To: <4F825BE7.80204@cn.fujitsu.com>

On Mon, Apr 09, 2012 at 11:47:51AM +0800, Ren Mingxin wrote:
>  On 04/04/2012 04:01 PM, Michael S. Tsirkin wrote:
> >On Mon, Apr 02, 2012 at 12:00:45PM -0700, Tejun Heo wrote:
> >>On Mon, Apr 02, 2012 at 11:56:18AM -0700, James Bottomley wrote:
> >>>So if we're agreed no other devices going forwards should ever use this
> >>>interface, is there any point unifying the interface?  No matter how
> >>>many caveats you hedge it round with, putting the API in a central place
> >>>will be a bit like a honey trap for careless bears.   It might be safer
> >>>just to leave it buried in the three current drivers.
> >>Yeah, that was my hope but I think it would be easier to enforce to
> >>have a common function which is clearly marked legacy so that new
> >>driver writers can go look for the naming code in the existing ones,
> >>find out they're all using the same function which is marked legacy
> >>and explains what to do for newer drivers.
> >I think I'm not the only one to be confused about the
> >preferred direction here.
> >James, do you agree to the approach above?
> >
> >It would be nice to fix virtio block for 3.4, so
> >how about this:
> >- I'll just apply the original bugfix patch for 3.4 -
> >   it only affects virtio
> 
> Sorry, about only affects virtio, I'm not very clear here:
> 1) Just duplicate the disk name format function in virtio_blk
>     like the original patch: https://lkml.org/lkml/2012/3/28/45

So I'd like to apply this, and we can discuss the
deduplication for 3.5. Please post a version of this that
1. isn't line-wrapped and doesn't have damaged whitespace
   so I can run git am on it
2. lists the # of duspported disks correctly as 26^3+(26^2+26)
   in the description

Thanks!

> 2) Move the disk name format function into block core like
>     this patch series but only affects virtio(not affect mtip32xx).
> Do you mean the 2) one or something else?
> 
> >- Ren will repost the refactoring patch on top, and we can
> >   keep up the discussion
> >
> >Ren if you agree, can you make this a two patch series please?
> >
> 
> Sure.
> 
> -- 
> Thanks,
> Ren