USB: fix mos7840 problem with minor numbers

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>

diff --git a/drivers/usb/serial/mos7840.c b/drivers/usb/serial/mos7840.c
index e8a3938..1911589 100644 (file)
--- a/drivers/usb/serial/mos7840.c
+++ b/drivers/usb/serial/mos7840.c
@@ -2453,9 +2453,14 @@ static int mos7840_startup(struct usb_serial *serial)
                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 usb_serial *serial)
 
        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 ::");