USB: fix needless failure under certain conditions

in devices.c we have a piece of code for dealing with losing in a race.
If we indeed lose the race we don't care whether our own memory allocation
worked. The check for that is so early that we return early even if we
don't have to.

Signed-off-by: Oliver Neukum <oneukum@suse.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

drivers/usb/core/devices.c

@@ -604,17 +604,18 @@ static unsigned int usb_device_poll(struct file *file, struct poll_table_struct
 	lock_kernel();
 	if (!st) {
 		st = kmalloc(sizeof(struct usb_device_status), GFP_KERNEL);
-		if (!st) {
-			unlock_kernel();
-			return POLLIN;
-		}
 
 		/* we may have dropped BKL - need to check for having lost the race */
 		if (file->private_data) {
 			kfree(st);
 			st = file->private_data;
 			goto lost_race;
 		}
+		/* we haven't lost - check for allocation failure now */
+		if (!st) {
+			unlock_kernel();
+			return POLLIN;
+		}
 
 		/*
 		 * need to prevent the module from being unloaded, since