[PATCH 4/6] USB: remove "locktree" routine from the hub driver

This patch (as892) removes the "locktree" routine from the hub driver.
It currently is used in only one place, by a single kernel thread;
hence it isn't doing any good.

Signed-off-by: Alan Stern <[email protected]>

---

Sorry, Dave -- I know how strongly you are attached to this code.  But the 
evolution in the design of the rest of usbcore, especially the suspend and 
resume parts, seems to have made it a dinosaur.

If it turns out there is some sequence of events where locktree would 
provide a useful purpose, we can always put it back.

Alan Stern


Index: usb-2.6/drivers/usb/core/hub.c
===================================================================
--- usb-2.6.orig/drivers/usb/core/hub.c
+++ usb-2.6/drivers/usb/core/hub.c
@@ -1062,49 +1062,6 @@ hub_ioctl(struct usb_interface *intf, un
 }
 
 
-/* grab device/port lock, returning index of that port (zero based).
- * protects the upstream link used by this device from concurrent
- * tree operations like suspend, resume, reset, and disconnect, which
- * apply to everything downstream of a given port.
- */
-static int locktree(struct usb_device *udev)
-{
-	int			t;
-	struct usb_device	*hdev;
-
-	if (!udev)
-		return -ENODEV;
-
-	/* root hub is always the first lock in the series */
-	hdev = udev->parent;
-	if (!hdev) {
-		usb_lock_device(udev);
-		return 0;
-	}
-
-	/* on the path from root to us, lock everything from
-	 * top down, dropping parent locks when not needed
-	 */
-	t = locktree(hdev);
-	if (t < 0)
-		return t;
-
-	/* everything is fail-fast once disconnect
-	 * processing starts
-	 */
-	if (udev->state == USB_STATE_NOTATTACHED) {
-		usb_unlock_device(hdev);
-		return -ENODEV;
-	}
-
-	/* when everyone grabs locks top->bottom,
-	 * non-overlapping work may be concurrent
-	 */
-	usb_lock_device(udev);
-	usb_unlock_device(hdev);
-	return udev->portnum;
-}
-
 static void recursively_mark_NOTATTACHED(struct usb_device *udev)
 {
 	int i;
@@ -2673,10 +2630,7 @@ static void hub_events(void)
 
 		/* Lock the device, then check to see if we were
 		 * disconnected while waiting for the lock to succeed. */
-		if (locktree(hdev) < 0) {
-			usb_put_intf(intf);
-			continue;
-		}
+		usb_lock_device(hdev);
 		if (hub != usb_get_intfdata(intf))
 			goto loop;
 


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