From: James Bottomley <James.Bottomley@HansenPartnership.com>
To: "K. Y. Srinivasan" <kys@microsoft.com>
Cc: gregkh@linuxfoundation.org, linux-kernel@vger.kernel.org,
devel@linuxdriverproject.org, ohering@suse.com,
hch@infradead.org, linux-scsi@vger.kernel.org
Subject: Re: Drivers: scsi
Date: Thu, 25 Oct 2012 07:25:20 +0900 [thread overview]
Message-ID: <1351117520.2494.8.camel@dabdike> (raw)
In-Reply-To: <1351095938-12204-1-git-send-email-kys@microsoft.com>
On Wed, 2012-10-24 at 09:25 -0700, K. Y. Srinivasan wrote:
> When the low level driver returns SCSI_MLQUEUE_DEVICE_BUSY,
> how is the command retried; I suspect the retry is done after some delay.
Delay depends mainly on I/O pressure and the unplug timer in the block
layer.
> Is this delay programmable? If the device state changes,
> can the low level driver notify upper layers that it can now handle
> the command that it had failed earlier with SCSI_MLQUEUE_DEVICE_BUSY.
In theory, you can call blk_run_queue() from the event handler that sees
the device become ready. I don't think any driver actually does this,
but I can't see it would cause any problem.
James
next prev parent reply other threads:[~2012-10-24 22:25 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-10-24 16:25 Drivers: scsi K. Y. Srinivasan
2012-10-24 22:25 ` James Bottomley [this message]
2012-10-24 22:34 ` KY Srinivasan
2012-10-24 22:34 ` KY Srinivasan
-- strict thread matches above, loose matches on Subject: below --
2012-11-03 16:40 K. Y. Srinivasan
2012-11-04 9:39 ` James Bottomley
2012-11-04 9:39 ` James Bottomley
2012-11-04 15:26 ` KY Srinivasan
2012-11-04 15:26 ` KY Srinivasan
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