USB: hub: fix up early-exit pathway in hub_activate

The early-exit pathway in hub_activate, added by commit e50293ef
("USB: fix invalid memory access in hub_activate()") needs
improvement.  It duplicates code that is already present at the end of
the subroutine, and it neglects to undo the effect of a
usb_autopm_get_interface_no_resume() call.

This patch fixes both problems by making the early-exit pathway jump
directly to the end of the subroutine.  It simplifies the code at the
end by merging two conditionals that actually test the same condition
although they appear different: If type < HUB_INIT3 then type must be
either HUB_INIT2 or HUB_INIT, and it can't be HUB_INIT because in that
case the subroutine would have exited earlier.
Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
CC: <stable@vger.kernel.org> #4.4+
Reviewed-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/usb/core/hub.c

@@ -1055,11 +1055,8 @@ static void hub_activate(struct usb_hub *hub, enum hub_activation_type type)
 		device_lock(hub->intfdev);
 
 		/* Was the hub disconnected while we were waiting? */
-		if (hub->disconnected) {
-			device_unlock(hub->intfdev);
-			kref_put(&hub->kref, hub_release);
-			return;
-		}
+		if (hub->disconnected)
+			goto disconnected;
 		if (type == HUB_INIT2)
 			goto init2;
 		goto init3;
@@ -1281,12 +1278,12 @@ static void hub_activate(struct usb_hub *hub, enum hub_activation_type type)
 	/* Scan all ports that need attention */
 	kick_hub_wq(hub);
 
+	if (type == HUB_INIT2 || type == HUB_INIT3) {
 		/* Allow autosuspend if it was suppressed */
-	if (type <= HUB_INIT3)
+ disconnected:
 		usb_autopm_put_interface_async(to_usb_interface(hub->intfdev));
-
-	if (type == HUB_INIT2 || type == HUB_INIT3)
 		device_unlock(hub->intfdev);
+	}
 
 	kref_put(&hub->kref, hub_release);
 }