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From: James Bottomley <James.Bottomley@steeleye.com>
To: Lee Xing <lxing@Crossroads.com>
Cc: SCSI Mailing List <linux-scsi@vger.kernel.org>,
	Douglas Gilbert <dougg@torque.net>
Subject: Re: Help - a question on scsi_debug and mid-layer
Date: 21 Jun 2004 14:12:40 -0500	[thread overview]
Message-ID: <1087845161.2077.75.camel@mulgrave> (raw)
In-Reply-To: <519672568F040C41B6FAC21ADF51B18FF03D@mailnode1.commstor.crossroads.com>

On Mon, 2004-06-21 at 13:53, Lee Xing wrote:
> I'm playing with scsi_debug (a low-level driver) of lk2.4 and notice that scsi_debug_queuecommand(...) defined in scsi_debug returns sometimes before the SCSI command completes (i.e. before done(cmd) is invoked), and sometimes after done(cmd) is invoked.  Can SCSI mid-layer really handle both cases without any problems, and why?
> 
> I assume that before scsi_debug_queuecommand() returns the control to mid-layer, mid-layer has no way to know whether that SCSI command has been successfully queued in low-level driver, therefore scsi_debug should not invoke done(cmd) before completing scsi_debug_queuecommand(...), correct?

I think if you look in Documentation/scsi/scsi_mid_low_api.txt (on 2.6)
you'll find it explains all of this under the entry for queuecommand.

James



      reply	other threads:[~2004-06-21 19:12 UTC|newest]

Thread overview: 2+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2004-06-21 18:53 Help - a question on scsi_debug and mid-layer Lee Xing
2004-06-21 19:12 ` James Bottomley [this message]

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