From mboxrd@z Thu Jan  1 00:00:00 1970
From: Elias Oltmanns <eo@nebensachen.de>
Subject: Re: [PATCH] SCSI: erase invalid data returned by device
Date: Wed, 16 Jul 2008 16:39:39 +0200
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	(Alan Stern's message of "Wed, 16 Jul 2008 10:28:12 -0400 (EDT)")
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To: Alan Stern <stern@rowland.harvard.edu>
Cc: James Bottomley <James.Bottomley@HansenPartnership.com>, Peter Teoh <htmldeveloper@gmail.com>, Maciej Rutecki <maciej.rutecki@gmail.com>, Boaz Harrosh <bharrosh@panasas.com>, USB Storage list <usb-storage@lists.one-eyed-alien.net>, SCSI development list <linux-scsi@vger.kernel.org>

Alan Stern <stern@rowland.harvard.edu> wrote:
> On Wed, 16 Jul 2008, Elias Oltmanns wrote:
>
>> Oh, I see. The name fooled me there, I suppose. So, the meaning of
>> req->data_len is inverted, as it were, when the LLDD performs the data
>> transfer, right?
>
> The inversion takes place in the midlayer, not in the LLDD.  Take a
> look inside scsi_io_completion():
>
> 	if (blk_pc_request(req)) { /* SG_IO ioctl from block level */
> 		...
> 		req->data_len = scsi_get_resid(cmd);
> 	}

Right, thanks for the hint.

Regards,

Elias