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>

1 files changed, 17 insertions, 5 deletions

diff --git a/drivers/usb/gadget/dummy_hcd.c b/drivers/usb/gadget/dummy_hcd.c
index d008d1360a7..c441d10c087 100644
--- a/drivers/usb/gadget/dummy_hcd.c
+++ b/drivers/usb/gadget/dummy_hcd.c
@@ -962,13 +962,13 @@ static struct platform_driver dummy_udc_driver = {
 
 static int dummy_urb_enqueue (
 	struct usb_hcd			*hcd,
-	struct usb_host_endpoint	*ep,
 	struct urb			*urb,
 	gfp_t				mem_flags
 ) {
 	struct dummy	*dum;
 	struct urbp	*urbp;
 	unsigned long	flags;
+	int		rc;
 
 	if (!urb->transfer_buffer && urb->transfer_buffer_length)
 		return -EINVAL;
@@ -980,6 +980,11 @@ static int dummy_urb_enqueue (
 
 	dum = hcd_to_dummy (hcd);
 	spin_lock_irqsave (&dum->lock, flags);
+	rc = usb_hcd_link_urb_to_ep(hcd, urb);
+	if (rc) {
+		kfree(urbp);
+		goto done;
+	}
 
 	if (!dum->udev) {
 		dum->udev = urb->dev;
@@ -997,22 +1002,28 @@ static int dummy_urb_enqueue (
 		mod_timer (&dum->timer, jiffies + 1);
 
 	spin_unlock_irqrestore (&dum->lock, flags);
-	return 0;
+ done:
+	return rc;
 }
 
-static int dummy_urb_dequeue (struct usb_hcd *hcd, struct urb *urb)
+static int dummy_urb_dequeue(struct usb_hcd *hcd, struct urb *urb, int status)
 {
 	struct dummy	*dum;
 	unsigned long	flags;
+	int		rc;
 
 	/* giveback happens automatically in timer callback,
 	 * so make sure the callback happens */
 	dum = hcd_to_dummy (hcd);
 	spin_lock_irqsave (&dum->lock, flags);
-	if (dum->rh_state != DUMMY_RH_RUNNING && !list_empty(&dum->urbp_list))
+
+	rc = usb_hcd_check_unlink_urb(hcd, urb, status);
+	if (!rc && dum->rh_state != DUMMY_RH_RUNNING &&
+			!list_empty(&dum->urbp_list))
 		mod_timer (&dum->timer, jiffies);
+
 	spin_unlock_irqrestore (&dum->lock, flags);
-	return 0;
+	return rc;
 }
 
 static void maybe_set_status (struct urb *urb, int status)
@@ -1511,6 +1522,7 @@ return_urb:
 		if (ep)
 			ep->already_seen = ep->setup_stage = 0;
 
+		usb_hcd_unlink_urb_from_ep(dummy_to_hcd(dum), urb);
 		spin_unlock (&dum->lock);
 		usb_hcd_giveback_urb (dummy_to_hcd(dum), urb);
 		spin_lock (&dum->lock);