USB: make HCDs responsible for managing endpoint queues

This patch (as954) implements a suggestion of David Brownell's.  Now
the host controller drivers are responsible for linking and unlinking
URBs to/from their endpoint queues.  This eliminates the possiblity of
strange situations where usbcore thinks an URB is linked but the HCD
thinks it isn't.  It also means HCDs no longer have to check for URBs
being dequeued before they were fully enqueued.

In addition to the core changes, this requires changing every host
controller driver and the root-hub URB handler.  For the most part the
required changes are fairly small; drivers have to call
usb_hcd_link_urb_to_ep() in their urb_enqueue method,
usb_hcd_check_unlink_urb() in their urb_dequeue method, and
usb_hcd_unlink_urb_from_ep() before giving URBs back.  A few HCDs make
matters more complicated by the way they split up the flow of control.

In addition some method interfaces get changed.  The endpoint argument
for urb_enqueue is now redundant so it is removed.  The unlink status
is required by usb_hcd_check_unlink_urb(), so it has been added to
urb_dequeue.

Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
CC: David Brownell <david-b@pacbell.net>
CC: Olav Kongas <ok@artecdesign.ee>
CC: Tony Olech <tony.olech@elandigitalsystems.com>
CC: Yoshihiro Shimoda <shimoda.yoshihiro@renesas.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

drivers/usb/host/ohci-hcd.c

@@ -117,7 +117,6 @@ MODULE_PARM_DESC (no_handshake, "true (not default) disables BIOS handshake");
  */
 static int ohci_urb_enqueue (
 	struct usb_hcd	*hcd,
-	struct usb_host_endpoint *ep,
 	struct urb	*urb,
 	gfp_t		mem_flags
 ) {
@@ -134,7 +133,7 @@ static int ohci_urb_enqueue (
 #endif
 
 	/* every endpoint has a ed, locate and maybe (re)initialize it */
-	if (! (ed = ed_get (ohci, ep, urb->dev, pipe, urb->interval)))
+	if (! (ed = ed_get (ohci, urb->ep, urb->dev, pipe, urb->interval)))
 		return -ENOMEM;
 
 	/* for the private part of the URB we need the number of TDs (size) */
@@ -199,22 +198,17 @@ static int ohci_urb_enqueue (
 		retval = -ENODEV;
 		goto fail;
 	}
-
-	/* in case of unlink-during-submit */
-	spin_lock (&urb->lock);
-	if (urb->status != -EINPROGRESS) {
-		spin_unlock (&urb->lock);
-		urb->hcpriv = urb_priv;
-		finish_urb (ohci, urb);
-		retval = 0;
+	retval = usb_hcd_link_urb_to_ep(hcd, urb);
+	if (retval)
 		goto fail;
-	}
 
 	/* schedule the ed if needed */
 	if (ed->state == ED_IDLE) {
 		retval = ed_schedule (ohci, ed);
-		if (retval < 0)
-			goto fail0;
+		if (retval < 0) {
+			usb_hcd_unlink_urb_from_ep(hcd, urb);
+			goto fail;
+		}
 		if (ed->type == PIPE_ISOCHRONOUS) {
 			u16	frame = ohci_frame_no(ohci);
 
@@ -238,8 +232,6 @@ static int ohci_urb_enqueue (
 	urb->hcpriv = urb_priv;
 	td_submit_urb (ohci, urb);
 
-fail0:
-	spin_unlock (&urb->lock);
 fail:
 	if (retval)
 		urb_free_priv (ohci, urb_priv);
@@ -253,17 +245,21 @@ fail:
  * asynchronously, and we might be dealing with an urb that's
  * partially transferred, or an ED with other urbs being unlinked.
  */
-static int ohci_urb_dequeue (struct usb_hcd *hcd, struct urb *urb)
+static int ohci_urb_dequeue(struct usb_hcd *hcd, struct urb *urb, int status)
 {
 	struct ohci_hcd		*ohci = hcd_to_ohci (hcd);
 	unsigned long		flags;
+	int			rc;
 
 #ifdef OHCI_VERBOSE_DEBUG
 	urb_print (urb, "UNLINK", 1);
 #endif
 
 	spin_lock_irqsave (&ohci->lock, flags);
-	if (HC_IS_RUNNING(hcd->state)) {
+	rc = usb_hcd_check_unlink_urb(hcd, urb, status);
+	if (rc) {
+		;	/* Do nothing */
+	} else if (HC_IS_RUNNING(hcd->state)) {
 		urb_priv_t  *urb_priv;
 
 		/* Unless an IRQ completed the unlink while it was being
@@ -284,7 +280,7 @@ static int ohci_urb_dequeue (struct usb_hcd *hcd, struct urb *urb)
 			finish_urb (ohci, urb);
 	}
 	spin_unlock_irqrestore (&ohci->lock, flags);
-	return 0;
+	return rc;
 }
 
 /*-------------------------------------------------------------------------*/