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, 18 insertions, 8 deletions

diff --git a/drivers/usb/host/sl811-hcd.c b/drivers/usb/host/sl811-hcd.c
index 4cfa3ff2c993..3d3a63d002c5 100644
--- a/drivers/usb/host/sl811-hcd.c
+++ b/drivers/usb/host/sl811-hcd.c
@@ -441,6 +441,7 @@ static void finish_request(
         urb->hcpriv = NULL;
         spin_unlock(&urb->lock);
 
+        usb_hcd_unlink_urb_from_ep(sl811_to_hcd(sl811), urb);
         spin_unlock(&sl811->lock);
         usb_hcd_giveback_urb(sl811_to_hcd(sl811), urb);
         spin_lock(&sl811->lock);
@@ -807,7 +808,6 @@ static int balance(struct sl811 *sl811, u16 period, u16 load)
 
 static int sl811h_urb_enqueue(
         struct usb_hcd          *hcd,
-        struct usb_host_endpoint *hep,
         struct urb              *urb,
         gfp_t                   mem_flags
 ) {
@@ -820,7 +820,8 @@ static int sl811h_urb_enqueue(
         struct sl811h_ep        *ep = NULL;
         unsigned long           flags;
         int                     i;
-        int                     retval = 0;
+        int                     retval;
+        struct usb_host_endpoint        *hep = urb->ep;
 
 #ifdef  DISABLE_ISO
         if (type == PIPE_ISOCHRONOUS)
@@ -838,7 +839,12 @@ static int sl811h_urb_enqueue(
                         || !HC_IS_RUNNING(hcd->state)) {
                 retval = -ENODEV;
                 kfree(ep);
-                goto fail;
+                goto fail_not_linked;
+        }
+        retval = usb_hcd_link_urb_to_ep(hcd, urb);
+        if (retval) {
+                kfree(ep);
+                goto fail_not_linked;
         }
 
         if (hep->hcpriv) {
@@ -965,23 +971,27 @@ static int sl811h_urb_enqueue(
         start_transfer(sl811);
         sl811_write(sl811, SL11H_IRQ_ENABLE, sl811->irq_enable);
 fail:
+        if (retval)
+                usb_hcd_unlink_urb_from_ep(hcd, urb);
+fail_not_linked:
         spin_unlock_irqrestore(&sl811->lock, flags);
         return retval;
 }
 
-static int sl811h_urb_dequeue(struct usb_hcd *hcd, struct urb *urb)
+static int sl811h_urb_dequeue(struct usb_hcd *hcd, struct urb *urb, int status)
 {
         struct sl811            *sl811 = hcd_to_sl811(hcd);
         struct usb_host_endpoint *hep;
         unsigned long           flags;
         struct sl811h_ep        *ep;
-        int                     retval = 0;
+        int                     retval;
 
         spin_lock_irqsave(&sl811->lock, flags);
-        hep = urb->hcpriv;
-        if (!hep)
+        retval = usb_hcd_check_unlink_urb(hcd, urb, status);
+        if (retval)
                 goto fail;
 
+        hep = urb->hcpriv;
         ep = hep->hcpriv;
         if (ep) {
                 /* finish right away if this urb can't be active ...
@@ -1029,8 +1039,8 @@ static int sl811h_urb_dequeue(struct usb_hcd *hcd, struct urb *urb)
                         VDBG("dequeue, urb %p active %s; wait4irq\n", urb,
                                 (sl811->active_a == ep) ? "A" : "B");
         } else
-fail:
                 retval = -EINVAL;
+ fail:
         spin_unlock_irqrestore(&sl811->lock, flags);
         return retval;
 }