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, 24 insertions, 13 deletions

diff --git a/drivers/usb/host/r8a66597-hcd.c b/drivers/usb/host/r8a66597-hcd.c
index 40a1de4c256e..94bb229df3bc 100644
--- a/drivers/usb/host/r8a66597-hcd.c
+++ b/drivers/usb/host/r8a66597-hcd.c
@@ -784,6 +784,9 @@ static void force_dequeue(struct r8a66597 *r8a66597, u16 pipenum, u16 address)
                 if (urb) {
                         urb->status = -ENODEV;
                         urb->hcpriv = NULL;
+                        usb_hcd_unlink_urb_from_ep(r8a66597_to_hcd(r8a66597),
+                                        urb);
+
                         spin_unlock(&r8a66597->lock);
                         usb_hcd_giveback_urb(r8a66597_to_hcd(r8a66597), urb);
                         spin_lock(&r8a66597->lock);
@@ -1131,6 +1134,8 @@ static void done(struct r8a66597 *r8a66597, struct r8a66597_td *td,
                         urb->start_frame = r8a66597_get_frame(hcd);
 
                 urb->hcpriv = NULL;
+                usb_hcd_unlink_urb_from_ep(r8a66597_to_hcd(r8a66597), urb);
+
                 spin_unlock(&r8a66597->lock);
                 usb_hcd_giveback_urb(hcd, urb);
                 spin_lock(&r8a66597->lock);
@@ -1722,21 +1727,25 @@ static struct r8a66597_td *r8a66597_make_td(struct r8a66597 *r8a66597,
 }
 
 static int r8a66597_urb_enqueue(struct usb_hcd *hcd,
-                                struct usb_host_endpoint *hep,
                                 struct urb *urb,
                                 gfp_t mem_flags)
 {
+        struct usb_host_endpoint *hep = urb->ep;
         struct r8a66597 *r8a66597 = hcd_to_r8a66597(hcd);
         struct r8a66597_td *td = NULL;
-        int ret = 0, request = 0;
+        int ret, request = 0;
         unsigned long flags;
 
         spin_lock_irqsave(&r8a66597->lock, flags);
         if (!get_urb_to_r8a66597_dev(r8a66597, urb)) {
                 ret = -ENODEV;
-                goto error;
+                goto error_not_linked;
         }
 
+        ret = usb_hcd_link_urb_to_ep(hcd, urb);
+        if (ret)
+                goto error_not_linked;
+
         if (!hep->hcpriv) {
                 hep->hcpriv = kzalloc(sizeof(struct r8a66597_pipe),
                                 GFP_ATOMIC);
@@ -1761,15 +1770,7 @@ static int r8a66597_urb_enqueue(struct usb_hcd *hcd,
         if (list_empty(&r8a66597->pipe_queue[td->pipenum]))
                 request = 1;
         list_add_tail(&td->queue, &r8a66597->pipe_queue[td->pipenum]);
-
-        spin_lock(&urb->lock);
-        if (urb->status != -EINPROGRESS) {
-                spin_unlock(&urb->lock);
-                ret = -EPIPE;
-                goto error;
-        }
         urb->hcpriv = td;
-        spin_unlock(&urb->lock);
 
         if (request) {
                 ret = start_transfer(r8a66597, td);
@@ -1781,17 +1782,26 @@ static int r8a66597_urb_enqueue(struct usb_hcd *hcd,
                 set_td_timer(r8a66597, td);
 
 error:
+        if (ret)
+                usb_hcd_unlink_urb_from_ep(hcd, urb);
+error_not_linked:
         spin_unlock_irqrestore(&r8a66597->lock, flags);
         return ret;
 }
 
-static int r8a66597_urb_dequeue(struct usb_hcd *hcd, struct urb *urb)
+static int r8a66597_urb_dequeue(struct usb_hcd *hcd, struct urb *urb,
+                int status)
 {
         struct r8a66597 *r8a66597 = hcd_to_r8a66597(hcd);
         struct r8a66597_td *td;
         unsigned long flags;
+        int rc;
 
         spin_lock_irqsave(&r8a66597->lock, flags);
+        rc = usb_hcd_check_unlink_urb(hcd, urb, status);
+        if (rc)
+                goto done;
+
         if (urb->hcpriv) {
                 td = urb->hcpriv;
                 pipe_stop(r8a66597, td->pipe);
@@ -1799,8 +1809,9 @@ static int r8a66597_urb_dequeue(struct usb_hcd *hcd, struct urb *urb)
                 disable_irq_empty(r8a66597, td->pipenum);
                 done(r8a66597, td, td->pipenum, urb);
         }
+ done:
         spin_unlock_irqrestore(&r8a66597->lock, flags);
-        return 0;
+        return rc;
 }
 
 static void r8a66597_endpoint_disable(struct usb_hcd *hcd,