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authorAlan Stern <stern@rowland.harvard.edu>2013-03-22 13:30:56 -0400
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2013-03-25 13:35:05 -0700
commit79bcf7b02ba3d45bafe81a2753cedb8ef49548e3 (patch)
treeda06b30b0fdd12dfb3286bed6a940bd2e4e0dfe0 /drivers/usb/host/ehci-q.c
parentc1fdb68e3d73741630ca16695cf9176c233be7ed (diff)
downloadlinux-stericsson-79bcf7b02ba3d45bafe81a2753cedb8ef49548e3.tar.gz
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>
Diffstat (limited to 'drivers/usb/host/ehci-q.c')
-rw-r--r--drivers/usb/host/ehci-q.c22
1 files changed, 8 insertions, 14 deletions
diff --git a/drivers/usb/host/ehci-q.c b/drivers/usb/host/ehci-q.c
index b824cb674898..c95f60d43b1a 100644
--- a/drivers/usb/host/ehci-q.c
+++ b/drivers/usb/host/ehci-q.c
@@ -292,8 +292,8 @@ static int qh_schedule (struct ehci_hcd *ehci, struct ehci_qh *qh);
/*
* Process and free completed qtds for a qh, returning URBs to drivers.
- * Chases up to qh->hw_current. Returns number of completions called,
- * indicating how much "real" work we did.
+ * Chases up to qh->hw_current. Returns nonzero if the caller should
+ * unlink qh.
*/
static unsigned
qh_completions (struct ehci_hcd *ehci, struct ehci_qh *qh)
@@ -302,13 +302,9 @@ qh_completions (struct ehci_hcd *ehci, struct ehci_qh *qh)
struct list_head *entry, *tmp;
int last_status;
int stopped;
- unsigned count = 0;
u8 state;
struct ehci_qh_hw *hw = qh->hw;
- if (unlikely (list_empty (&qh->qtd_list)))
- return count;
-
/* completions (or tasks on other cpus) must never clobber HALT
* till we've gone through and cleaned everything up, even when
* they add urbs to this qh's queue or mark them for unlinking.
@@ -345,7 +341,6 @@ qh_completions (struct ehci_hcd *ehci, struct ehci_qh *qh)
if (last) {
if (likely (last->urb != urb)) {
ehci_urb_done(ehci, last->urb, last_status);
- count++;
last_status = -EINPROGRESS;
}
ehci_qtd_free (ehci, last);
@@ -519,7 +514,6 @@ qh_completions (struct ehci_hcd *ehci, struct ehci_qh *qh)
/* last urb's completion might still need calling */
if (likely (last != NULL)) {
ehci_urb_done(ehci, last->urb, last_status);
- count++;
ehci_qtd_free (ehci, last);
}
@@ -566,7 +560,7 @@ qh_completions (struct ehci_hcd *ehci, struct ehci_qh *qh)
/* otherwise, unlink already started */
}
- return count;
+ return qh->needs_rescan;
}
/*-------------------------------------------------------------------------*/
@@ -1254,7 +1248,8 @@ static void end_unlink_async(struct ehci_hcd *ehci)
qh->qh_state = QH_STATE_IDLE;
qh->qh_next.qh = NULL;
- qh_completions(ehci, qh);
+ if (!list_empty(&qh->qtd_list))
+ qh_completions(ehci, qh);
if (!list_empty(&qh->qtd_list) &&
ehci->rh_state == EHCI_RH_RUNNING)
qh_link_async(ehci, qh);
@@ -1348,7 +1343,7 @@ static void scan_async (struct ehci_hcd *ehci)
while (ehci->qh_scan_next) {
qh = ehci->qh_scan_next;
ehci->qh_scan_next = qh->qh_next.qh;
- rescan:
+
/* clean any finished work for this qh */
if (!list_empty(&qh->qtd_list)) {
int temp;
@@ -1361,14 +1356,13 @@ static void scan_async (struct ehci_hcd *ehci)
* in single_unlink_async().
*/
temp = qh_completions(ehci, qh);
- if (qh->needs_rescan) {
+ if (unlikely(temp)) {
start_unlink_async(ehci, qh);
} else if (list_empty(&qh->qtd_list)
&& qh->qh_state == QH_STATE_LINKED) {
qh->unlink_cycle = ehci->async_unlink_cycle;
check_unlinks_later = true;
- } else if (temp != 0)
- goto rescan;
+ }
}
}