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From: James Bottomley <James.Bottomley@SteelEye.com>
To: Kristen Carlson Accardi <kristen.c.accardi@intel.com>
Cc: akpm@linux-foundation.org, jeff@garzik.org,
	linux-scsi@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [patch 0/3] clean gendisk out of scsi ULD structs
Date: Fri, 06 Jul 2007 15:02:49 -0500	[thread overview]
Message-ID: <1183752169.3448.93.camel@localhost.localdomain> (raw)
In-Reply-To: <20070705140636.6dbabd6f.kristen.c.accardi@intel.com>

On Thu, 2007-07-05 at 14:06 -0700, Kristen Carlson Accardi wrote:
> Since gendisk will now become part of struct scsi_device, we don't need
> to store this value in any private data structs where they already store
> scsi_device.  This series cleans up a few drivers which did this.

Actually, as Al pointed out, we do have lifetime rules issues with doing
this.  The problem is that gendisk itself always has a shorter lifetime
than scsi_device (not much shorter, usually, but if you execute a legal
ULD unbind manoeuvre you'll end up with a dangling gendisk pointer).

The other problem with taking gendisk out of the ULD structure and
putting it into the scsi_device is that for the sg driver, we have two
of them (one for the attached ULD and one for the sg driver).

The fundamental issue seems to be that the gendisk is the holder of all
the other info (queue, ULD etc) not vice versa ... and this patch is
trying to reverse that relationship.

James



  parent reply	other threads:[~2007-07-06 20:03 UTC|newest]

Thread overview: 8+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2007-07-05 21:06 [patch 0/3] clean gendisk out of scsi ULD structs Kristen Carlson Accardi
2007-07-05 22:09 ` Douglas Gilbert
2007-07-05 23:03   ` Al Viro
2007-07-05 23:02 ` Al Viro
2007-07-05 23:14   ` James Bottomley
2007-07-06 20:02 ` James Bottomley [this message]
2007-07-07  3:25   ` Douglas Gilbert
2007-07-07 15:15     ` James Bottomley

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