USB: EHCI: add pointer to end of async-unlink list
This patch (as1570) adds a pointer for the end of ehci-hcd's
async-unlink list. The list (which is actually a queue) is singly
linked, so having a pointer to its end makes adding new entries easier
-- there's no longer any need to scan through the whole list.
In principle it could be changed to a standard doubly-linked list. It
turns out that doing so actually makes the code less clear, so I'm
leaving it as is.
Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
diff --git a/drivers/usb/host/ehci-hcd.c b/drivers/usb/host/ehci-hcd.c
index efee426..8b75e42 100644
--- a/drivers/usb/host/ehci-hcd.c
+++ b/drivers/usb/host/ehci-hcd.c
@@ -1041,14 +1041,9 @@
/* defer till later if busy */
if (ehci->async_unlink) {
- struct ehci_qh *last;
-
- for (last = ehci->async_unlink;
- last->unlink_next;
- last = last->unlink_next)
- continue;
qh->qh_state = QH_STATE_UNLINK_WAIT;
- last->unlink_next = qh;
+ ehci->async_unlink_last->unlink_next = qh;
+ ehci->async_unlink_last = qh;
/* start IAA cycle */
} else
diff --git a/drivers/usb/host/ehci-q.c b/drivers/usb/host/ehci-q.c
index 8e80cde..5193612 100644
--- a/drivers/usb/host/ehci-q.c
+++ b/drivers/usb/host/ehci-q.c
@@ -1227,6 +1227,8 @@
qh->qh_state = QH_STATE_UNLINK;
ehci->async_unlink = qh;
+ if (!qh->unlink_next)
+ ehci->async_unlink_last = qh;
prev = ehci->async;
while (prev->qh_next.qh != qh)
diff --git a/drivers/usb/host/ehci.h b/drivers/usb/host/ehci.h
index 3c6c07c..475f23e 100644
--- a/drivers/usb/host/ehci.h
+++ b/drivers/usb/host/ehci.h
@@ -82,6 +82,7 @@
struct ehci_qh *async;
struct ehci_qh *dummy; /* For AMD quirk use */
struct ehci_qh *async_unlink;
+ struct ehci_qh *async_unlink_last;
struct ehci_qh *qh_scan_next;
unsigned scanning : 1;