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 66259dc..5c82bba 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;
 		}
 	}
 }