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, 31 insertions, 12 deletions

diff --git a/drivers/usb/host/ehci-sched.c b/drivers/usb/host/ehci-sched.c
index e682f2342ef8..8b267b3fd2bb 100644
--- a/drivers/usb/host/ehci-sched.c
+++ b/drivers/usb/host/ehci-sched.c
@@ -797,7 +797,6 @@ done:
 
 static int intr_submit (
         struct ehci_hcd         *ehci,
-        struct usb_host_endpoint *ep,
         struct urb              *urb,
         struct list_head        *qtd_list,
         gfp_t                   mem_flags
@@ -805,23 +804,26 @@ static int intr_submit (
         unsigned                epnum;
         unsigned long           flags;
         struct ehci_qh          *qh;
-        int                     status = 0;
+        int                     status;
         struct list_head        empty;
 
         /* get endpoint and transfer/schedule data */
-        epnum = ep->desc.bEndpointAddress;
+        epnum = urb->ep->desc.bEndpointAddress;
 
         spin_lock_irqsave (&ehci->lock, flags);
 
         if (unlikely(!test_bit(HCD_FLAG_HW_ACCESSIBLE,
                         &ehci_to_hcd(ehci)->flags))) {
                 status = -ESHUTDOWN;
-                goto done;
+                goto done_not_linked;
         }
+        status = usb_hcd_link_urb_to_ep(ehci_to_hcd(ehci), urb);
+        if (unlikely(status))
+                goto done_not_linked;
 
         /* get qh and force any scheduling errors */
         INIT_LIST_HEAD (&empty);
-        qh = qh_append_tds (ehci, urb, &empty, epnum, &ep->hcpriv);
+        qh = qh_append_tds(ehci, urb, &empty, epnum, &urb->ep->hcpriv);
         if (qh == NULL) {
                 status = -ENOMEM;
                 goto done;
@@ -832,13 +834,16 @@ static int intr_submit (
         }
 
         /* then queue the urb's tds to the qh */
-        qh = qh_append_tds (ehci, urb, qtd_list, epnum, &ep->hcpriv);
+        qh = qh_append_tds(ehci, urb, qtd_list, epnum, &urb->ep->hcpriv);
         BUG_ON (qh == NULL);
 
         /* ... update usbfs periodic stats */
         ehci_to_hcd(ehci)->self.bandwidth_int_reqs++;
 
 done:
+        if (unlikely(status))
+                usb_hcd_unlink_urb_from_ep(ehci_to_hcd(ehci), urb);
+done_not_linked:
         spin_unlock_irqrestore (&ehci->lock, flags);
         if (status)
                 qtd_list_free (ehci, urb, qtd_list);
@@ -1686,12 +1691,19 @@ static int itd_submit (struct ehci_hcd *ehci, struct urb *urb,
         /* schedule ... need to lock */
         spin_lock_irqsave (&ehci->lock, flags);
         if (unlikely(!test_bit(HCD_FLAG_HW_ACCESSIBLE,
-                               &ehci_to_hcd(ehci)->flags)))
+                               &ehci_to_hcd(ehci)->flags))) {
                 status = -ESHUTDOWN;
-        else
-                status = iso_stream_schedule (ehci, urb, stream);
+                goto done_not_linked;
+        }
+        status = usb_hcd_link_urb_to_ep(ehci_to_hcd(ehci), urb);
+        if (unlikely(status))
+                goto done_not_linked;
+        status = iso_stream_schedule(ehci, urb, stream);
         if (likely (status == 0))
                 itd_link_urb (ehci, urb, ehci->periodic_size << 3, stream);
+        else
+                usb_hcd_unlink_urb_from_ep(ehci_to_hcd(ehci), urb);
+done_not_linked:
         spin_unlock_irqrestore (&ehci->lock, flags);
 
 done:
@@ -2049,12 +2061,19 @@ static int sitd_submit (struct ehci_hcd *ehci, struct urb *urb,
         /* schedule ... need to lock */
         spin_lock_irqsave (&ehci->lock, flags);
         if (unlikely(!test_bit(HCD_FLAG_HW_ACCESSIBLE,
-                               &ehci_to_hcd(ehci)->flags)))
+                               &ehci_to_hcd(ehci)->flags))) {
                 status = -ESHUTDOWN;
-        else
-                status = iso_stream_schedule (ehci, urb, stream);
+                goto done_not_linked;
+        }
+        status = usb_hcd_link_urb_to_ep(ehci_to_hcd(ehci), urb);
+        if (unlikely(status))
+                goto done_not_linked;
+        status = iso_stream_schedule(ehci, urb, stream);
         if (status == 0)
                 sitd_link_urb (ehci, urb, ehci->periodic_size << 3, stream);
+        else
+                usb_hcd_unlink_urb_from_ep(ehci_to_hcd(ehci), urb);
+done_not_linked:
         spin_unlock_irqrestore (&ehci->lock, flags);
 
 done: