[[email protected]: Patch to USB Storage to allow for LUNs greater than 2TB]

The message below implements a recently discussed patch to allow 16-byte
CDBs through usb-storage, which allows device support up to 2Tb.

I didn't see a patch come from anywhere else, so I'm forwarding this one.
Then again, I just got back from vacation 9 timezones away, so I'm still
catching up...

Signed-off-by: Matthew Dharm <[email protected]>

Greg, please apply.

Matt

----- Forwarded message from Richard Sharpe <[email protected]> -----

Date: Fri, 5 Oct 2007 06:27:43 -0700 (PDT)
From: Richard Sharpe <[email protected]>
Subject: Patch to USB Storage to allow for LUNs greater than 2TB
To: Matthew Dharm <[email protected]>
X-Spam-Status: No, score=-2.5 required=5.0 tests=BAYES_00,FORGED_RCVD_HELO
	autolearn=ham version=3.1.9
X-Virus-Status: Clean

Hi,

Attached is a very small patch (several comment lines) and a one-line coded 
change) that allows for USB storage devices that are larger than 2TB.

At the company where I work we need such support, and one of my co-workers, 
Jane Liu, pointed out that SCSI low-layer drivers need to specify what size 
CDBs they accept. After looking through the code it became obvious that the 
current USB Storage code accepted the default of 12-byte CDBs, so I changed 
it to accept 16-byte CDBs. This allows our device to work.

I this helps other people.

Signed-off-by: Richard Sharpe <[email protected]>

Regards
-------
Richard Sharpe, rsharpe[at]richardsharpe.com, rsharpe[at]samba.org,
sharpe[at]ethereal.com, http://www.richardsharpe.com

Content-Description: USB Storage GT 2TB
--- linux-2.6.22/drivers/usb/storage/usb.orig.c	2007-10-03 22:26:59.000000000 -0700
+++ linux-2.6.22/drivers/usb/storage/usb.c	2007-10-03 22:29:05.000000000 -0700
@@ -967,6 +967,10 @@ static int storage_probe(struct usb_inte
 		return -ENOMEM;
 	}
 
+	/*
+	 * Allow 16-byte CDBs and thus > 2TB
+	 */
+	host->max_cmd_len = 16; 
 	us = host_to_us(host);
 	memset(us, 0, sizeof(struct us_data));
 	mutex_init(&(us->dev_mutex));


----- End forwarded message -----

-- 
Matthew Dharm                              Home: [email protected] 
Maintainer, Linux USB Mass Storage Driver

Hi.  I have my back hairs caught in my computer fan.
					-- Customer
User Friendly, 8/20/1998

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