usb_serial_suspend(): buggy(?) code

usb_serial_suspend(): buggy(?) code

[Adrian Bunk]

Commit ec22559e0b7a05283a3413bda5d177e42c950e23 added the following 
function to drivers/usb/serial/usb-serial.c:

<--  snip  -->

...
int usb_serial_suspend(struct usb_interface *intf, pm_message_t message)
{
        struct usb_serial *serial = usb_get_intfdata(intf);
        struct usb_serial_port *port;
        int i, r = 0;

        if (serial) {
                for (i = 0; i < serial->num_ports; ++i) {
                        port = serial->port[i];
                        if (port)
                                kill_traffic(port);
                }
        }

        if (serial->type->suspend)
                serial->type->suspend(serial, message);

        return r;
}
...

<--  snip  -->

The Coverity checker spotted the inconsequent NULL checking for "serial".

Looking at the code it also doesn't seem to have been intended to always 
return 0.

cu
Adrian

-- 

       "Is there not promise of rain?" Ling Tan asked suddenly out
        of the darkness. There had been need of rain for many days.
       "Only a promise," Lao Er said.
                                       Pearl S. Buck - Dragon Seed

Re: usb_serial_suspend(): buggy(?) code

[Oliver Neukum]

Am Montag 23 Juli 2007 schrieb Adrian Bunk:
> Commit ec22559e0b7a05283a3413bda5d177e42c950e23 added the following 
> function to drivers/usb/serial/usb-serial.c:
> 
[..]
> 
> The Coverity checker spotted the inconsequent NULL checking for "serial".
> 
> Looking at the code it also doesn't seem to have been intended to always 
> return 0.

Coverity is right. The check for NULL is wrongly done and the error
return is lost.

	Regards
		Oliver
Signed-off-by: Oliver Neukum <oneukum@suse.de>
--

--- a/drivers/usb/serial/usb-serial.c	2007-07-23 08:47:35.000000000 +0200
+++ b/drivers/usb/serial/usb-serial.c	2007-07-23 08:49:20.000000000 +0200
@@ -1077,16 +1077,17 @@ int usb_serial_suspend(struct usb_interf
 	struct usb_serial_port *port;
 	int i, r = 0;
 
-	if (serial) {
-		for (i = 0; i < serial->num_ports; ++i) {
-			port = serial->port[i];
-			if (port)
-				kill_traffic(port);
-		}
+	if (!serial) /* device has been disconnected */
+		return 0;
+
+	for (i = 0; i < serial->num_ports; ++i) {
+		port = serial->port[i];
+		if (port)
+			kill_traffic(port);
 	}
 
 	if (serial->type->suspend)
-		serial->type->suspend(serial, message);
+		r = serial->type->suspend(serial, message);
 
 	return r;
 }