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From: Tejun Heo <htejun@gmail.com>
To: James Bottomley <James.Bottomley@HansenPartnership.com>
Cc: Mark Lord <liml@rtr.ca>, Matthew Wilcox <matthew@wil.cx>,
	linux-ide@vger.kernel.org, linux-kernel@vger.kernel.org,
	Jeff Garzik <jeff@garzik.org>
Subject: Re: ata_ram driver
Date: Fri, 07 Mar 2008 09:43:22 +0900	[thread overview]
Message-ID: <47D08FAA.7070001@gmail.com> (raw)
In-Reply-To: <1204850398.3062.111.camel@localhost.localdomain>

James Bottomley wrote:
> On Fri, 2008-03-07 at 09:28 +0900, Tejun Heo wrote:
>> James Bottomley wrote:
>>>> Yeap, sure.  It's the combination of things that always made me put this
>>>> off.  Is there a function I can call to just shutdown the host instead
>>>> of destroying it?
>>> Not really ... the process of unbinding the ULDs causes their remove
>>> methods to call shudown.  It is possible to separate this in the ULDS;
>>> but the original design was to make remove and shutdown be similar for
>>> the very reason that if you're removing the driver with unflushed data
>>> in the cache, we'd really like it flushed (flush is called from
>>> shutdown) because you have no way to talk to the device after this
>>> without reinserting the driver.
>> The problem is that libata EH and other stuff aren't ready to let go of
>> the SCSI host up until the last moment and that last moment can't be
>> moved before SCSI host destruction because shutdown sequence (flush and
>> spindown) requires live EH.  I think this can be solved by shooting down
>> individual sdev's instead of destroying the scsi_host.
> 
> Basically what scsi_scan.c:scsi_forget_host() does?  It's used
> internally at the moment, but I suppose we could export it.

Yeap, exactly.  I'll prep a patch after breakfast.

-- 
tejun

  reply	other threads:[~2008-03-07  0:43 UTC|newest]

Thread overview: 15+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2008-02-22 20:09 ata_ram driver Matthew Wilcox
2008-02-22 21:27 ` Mark Lord
2008-03-06  8:21   ` Tejun Heo
2008-03-06 15:28     ` James Bottomley
2008-03-06 23:55       ` Tejun Heo
2008-03-07  0:01         ` James Bottomley
2008-03-07  0:13           ` Tejun Heo
2008-03-07  0:22             ` James Bottomley
2008-03-07  0:28               ` Tejun Heo
2008-03-07  0:39                 ` James Bottomley
2008-03-07  0:43                   ` Tejun Heo [this message]
2008-03-07  3:08                     ` [PATCH 1/2] scsi: export scsi_forget_host() Tejun Heo
2008-03-07  3:11                       ` [PATCH 2/2] libata: kill SCSI devices before detaching ata_host Tejun Heo
2008-03-07  2:16                 ` ata_ram driver Jeff Garzik
2008-03-07  2:44                   ` James Bottomley

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