[15/18] USB: fix mos7840 problem with minor numbers

[Greg KH <gregkh@suse.de>]

2.6.27-stable review patch.  If anyone has any objections, please let us know.

------------------
From: Tony Cook <tony-cook@bigpond.com>

commit 37768adf9a1d49aeac0db1ba3dc28b3274b7b789 upstream

This patch fixes a problem with any mos7840 device where the use of the
field "minor" before it is initialised results in all the devices being
overlaid in memory (minor = 0 for all instances)

Contributed by: Phillip Branch

Backported to .27 by Christoph Biedl <linux-kernel.bfrz@manchmal.in-ulm.de>

Signed-off-by: Tony Cook <tony-cook@bigpond.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>


---
 drivers/usb/serial/mos7840.c |   21 ++++++++++++++-------
 1 file changed, 14 insertions(+), 7 deletions(-)

--- a/drivers/usb/serial/mos7840.c
+++ b/drivers/usb/serial/mos7840.c
@@ -2453,9 +2453,14 @@ static int mos7840_startup(struct usb_se
 		mos7840_set_port_private(serial->port[i], mos7840_port);
 		spin_lock_init(&mos7840_port->pool_lock);
 
-		mos7840_port->port_num = ((serial->port[i]->number -
-					   (serial->port[i]->serial->minor)) +
-					  1);
+		/* minor is not initialised until later by
+		 * usb-serial.c:get_free_serial() and cannot therefore be used
+		 * to index device instances */
+		mos7840_port->port_num = i + 1;
+		dbg ("serial->port[i]->number = %d", serial->port[i]->number);
+		dbg ("serial->port[i]->serial->minor = %d", serial->port[i]->serial->minor);
+		dbg ("mos7840_port->port_num = %d", mos7840_port->port_num);
+		dbg ("serial->minor = %d", serial->minor);
 
 		if (mos7840_port->port_num == 1) {
 			mos7840_port->SpRegOffset = 0x0;
@@ -2666,10 +2671,12 @@ static void mos7840_disconnect(struct us
 
 	for (i = 0; i < serial->num_ports; ++i) {
 		mos7840_port = mos7840_get_port_private(serial->port[i]);
-		spin_lock_irqsave(&mos7840_port->pool_lock, flags);
-		mos7840_port->zombie = 1;
-		spin_unlock_irqrestore(&mos7840_port->pool_lock, flags);
-		usb_kill_urb(mos7840_port->control_urb);
+		if (mos7840_port) {
+			spin_lock_irqsave(&mos7840_port->pool_lock, flags);
+			mos7840_port->zombie = 1;
+			spin_unlock_irqrestore(&mos7840_port->pool_lock, flags);
+			usb_kill_urb(mos7840_port->control_urb);
+		}
 	}
 
 	dbg("%s\n", "Thank u ::");