USB: EHCI: change return value of qh_completions()

This patch (as1658) cleans up the usage of qh_completions() in
ehci-hcd.  Currently the function's return value indicates whether any
URBs were given back; the idea was that the caller can scan the QH
over again to handle any URBs that were dequeued by a completion
handler.  This is not necessary; when qh_completions() is ready to
give back dequeued URBs, it does its own rescanning.

Therefore the new return value will be a flag indicating whether the
caller needs to unlink the QH.  This is more convenient than forcing
the caller to check qh->needs_rescan, and it makes a lot more sense --
why should "needs_rescan" imply that an unlink is needed?  The callers
are also changed to remove the unneeded rescans.

Lastly, the check for whether qh->qtd_list is non-empty is removed
from the start of qh_completions().  Two of the callers have to make
this test anyway, so the same test can simply be added to the other
two callers.

Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

1 files changed, 5 insertions, 7 deletions

diff --git a/drivers/usb/host/ehci-sched.c b/drivers/usb/host/ehci-sched.c
index 66259dc7822e..5c82bbab9a48 100644
--- a/drivers/usb/host/ehci-sched.c
+++ b/drivers/usb/host/ehci-sched.c
@@ -649,7 +649,8 @@ static void end_unlink_intr(struct ehci_hcd *ehci, struct ehci_qh *qh)
         qh->qh_state = QH_STATE_IDLE;
         hw->hw_next = EHCI_LIST_END(ehci);
 
-        qh_completions(ehci, qh);
+        if (!list_empty(&qh->qtd_list))
+                qh_completions(ehci, qh);
 
         /* reschedule QH iff another request is queued */
         if (!list_empty(&qh->qtd_list) && ehci->rh_state == EHCI_RH_RUNNING) {
@@ -914,7 +915,7 @@ static void scan_intr(struct ehci_hcd *ehci)
 
         list_for_each_entry_safe(qh, ehci->qh_scan_next, &ehci->intr_qh_list,
                         intr_node) {
- rescan:
+
                 /* clean any finished work for this qh */
                 if (!list_empty(&qh->qtd_list)) {
                         int temp;
@@ -927,12 +928,9 @@ static void scan_intr(struct ehci_hcd *ehci)
                          * in qh_unlink_periodic().
                          */
                         temp = qh_completions(ehci, qh);
-                        if (unlikely(qh->needs_rescan ||
-                                        (list_empty(&qh->qtd_list) &&
-                                                qh->qh_state == QH_STATE_LINKED)))
+                        if (unlikely(temp || (list_empty(&qh->qtd_list) &&
+                                        qh->qh_state == QH_STATE_LINKED)))
                                 start_unlink_intr(ehci, qh);
-                        else if (temp != 0)
-                                goto rescan;
                 }
         }
 }