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, 9 insertions, 5 deletions

diff --git a/drivers/usb/host/ehci-q.c b/drivers/usb/host/ehci-q.c
index 140bfa4..1da2de4 100644
--- a/drivers/usb/host/ehci-q.c
+++ b/drivers/usb/host/ehci-q.c
@@ -262,6 +262,7 @@ __acquires(ehci->lock)
 #endif
 
 	/* complete() can reenter this HCD */
+	usb_hcd_unlink_urb_from_ep(ehci_to_hcd(ehci), urb);
 	spin_unlock (&ehci->lock);
 	usb_hcd_giveback_urb (ehci_to_hcd(ehci), urb);
 	spin_lock (&ehci->lock);
@@ -913,7 +914,6 @@ static struct ehci_qh *qh_append_tds (
 static int
 submit_async (
 	struct ehci_hcd		*ehci,
-	struct usb_host_endpoint *ep,
 	struct urb		*urb,
 	struct list_head	*qtd_list,
 	gfp_t			mem_flags
@@ -922,10 +922,10 @@ submit_async (
 	int			epnum;
 	unsigned long		flags;
 	struct ehci_qh		*qh = NULL;
-	int			rc = 0;
+	int			rc;
 
 	qtd = list_entry (qtd_list->next, struct ehci_qtd, qtd_list);
-	epnum = ep->desc.bEndpointAddress;
+	epnum = urb->ep->desc.bEndpointAddress;
 
 #ifdef EHCI_URB_TRACE
 	ehci_dbg (ehci,
@@ -933,7 +933,7 @@ submit_async (
 		__FUNCTION__, urb->dev->devpath, urb,
 		epnum & 0x0f, (epnum & USB_DIR_IN) ? "in" : "out",
 		urb->transfer_buffer_length,
-		qtd, ep->hcpriv);
+		qtd, urb->ep->hcpriv);
 #endif
 
 	spin_lock_irqsave (&ehci->lock, flags);
@@ -942,9 +942,13 @@ submit_async (
 		rc = -ESHUTDOWN;
 		goto done;
 	}
+	rc = usb_hcd_link_urb_to_ep(ehci_to_hcd(ehci), urb);
+	if (unlikely(rc))
+		goto done;
 
-	qh = qh_append_tds (ehci, urb, qtd_list, epnum, &ep->hcpriv);
+	qh = qh_append_tds(ehci, urb, qtd_list, epnum, &urb->ep->hcpriv);
 	if (unlikely(qh == NULL)) {
+		usb_hcd_unlink_urb_from_ep(ehci_to_hcd(ehci), urb);
 		rc = -ENOMEM;
 		goto done;
 	}