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-rw-r--r--drivers/usb/core/hcd.c3
-rw-r--r--drivers/usb/core/urb.c44
-rw-r--r--include/linux/usb.h3
3 files changed, 48 insertions, 2 deletions
diff --git a/drivers/usb/core/hcd.c b/drivers/usb/core/hcd.c
index 460bb59cb655..149cdf129293 100644
--- a/drivers/usb/core/hcd.c
+++ b/drivers/usb/core/hcd.c
@@ -1652,6 +1652,7 @@ int usb_hcd_unlink_urb (struct urb *urb, int status)
static void __usb_hcd_giveback_urb(struct urb *urb)
{
struct usb_hcd *hcd = bus_to_hcd(urb->dev->bus);
+ struct usb_anchor *anchor = urb->anchor;
int status = urb->unlinked;
unsigned long flags;
@@ -1663,6 +1664,7 @@ static void __usb_hcd_giveback_urb(struct urb *urb)
unmap_urb_for_dma(hcd, urb);
usbmon_urb_complete(&hcd->self, urb, status);
+ usb_anchor_suspend_wakeups(anchor);
usb_unanchor_urb(urb);
/* pass ownership to the completion handler */
@@ -1682,6 +1684,7 @@ static void __usb_hcd_giveback_urb(struct urb *urb)
urb->complete(urb);
local_irq_restore(flags);
+ usb_anchor_resume_wakeups(anchor);
atomic_dec(&urb->use_count);
if (unlikely(atomic_read(&urb->reject)))
wake_up(&usb_kill_urb_queue);
diff --git a/drivers/usb/core/urb.c b/drivers/usb/core/urb.c
index c12bc790a6a7..e62208356c89 100644
--- a/drivers/usb/core/urb.c
+++ b/drivers/usb/core/urb.c
@@ -138,13 +138,19 @@ void usb_anchor_urb(struct urb *urb, struct usb_anchor *anchor)
}
EXPORT_SYMBOL_GPL(usb_anchor_urb);
+static int usb_anchor_check_wakeup(struct usb_anchor *anchor)
+{
+ return atomic_read(&anchor->suspend_wakeups) == 0 &&
+ list_empty(&anchor->urb_list);
+}
+
/* Callers must hold anchor->lock */
static void __usb_unanchor_urb(struct urb *urb, struct usb_anchor *anchor)
{
urb->anchor = NULL;
list_del(&urb->anchor_list);
usb_put_urb(urb);
- if (list_empty(&anchor->urb_list))
+ if (usb_anchor_check_wakeup(anchor))
wake_up(&anchor->wait);
}
@@ -846,6 +852,39 @@ void usb_unlink_anchored_urbs(struct usb_anchor *anchor)
EXPORT_SYMBOL_GPL(usb_unlink_anchored_urbs);
/**
+ * usb_anchor_suspend_wakeups
+ * @anchor: the anchor you want to suspend wakeups on
+ *
+ * Call this to stop the last urb being unanchored from waking up any
+ * usb_wait_anchor_empty_timeout waiters. This is used in the hcd urb give-
+ * back path to delay waking up until after the completion handler has run.
+ */
+void usb_anchor_suspend_wakeups(struct usb_anchor *anchor)
+{
+ if (anchor)
+ atomic_inc(&anchor->suspend_wakeups);
+}
+EXPORT_SYMBOL_GPL(usb_anchor_suspend_wakeups);
+
+/**
+ * usb_anchor_resume_wakeups
+ * @anchor: the anchor you want to resume wakeups on
+ *
+ * Allow usb_wait_anchor_empty_timeout waiters to be woken up again, and
+ * wake up any current waiters if the anchor is empty.
+ */
+void usb_anchor_resume_wakeups(struct usb_anchor *anchor)
+{
+ if (!anchor)
+ return;
+
+ atomic_dec(&anchor->suspend_wakeups);
+ if (usb_anchor_check_wakeup(anchor))
+ wake_up(&anchor->wait);
+}
+EXPORT_SYMBOL_GPL(usb_anchor_resume_wakeups);
+
+/**
* usb_wait_anchor_empty_timeout - wait for an anchor to be unused
* @anchor: the anchor you want to become unused
* @timeout: how long you are willing to wait in milliseconds
@@ -858,7 +897,8 @@ EXPORT_SYMBOL_GPL(usb_unlink_anchored_urbs);
int usb_wait_anchor_empty_timeout(struct usb_anchor *anchor,
unsigned int timeout)
{
- return wait_event_timeout(anchor->wait, list_empty(&anchor->urb_list),
+ return wait_event_timeout(anchor->wait,
+ usb_anchor_check_wakeup(anchor),
msecs_to_jiffies(timeout));
}
EXPORT_SYMBOL_GPL(usb_wait_anchor_empty_timeout);
diff --git a/include/linux/usb.h b/include/linux/usb.h
index fa8bedf06c6e..055ba74bee80 100644
--- a/include/linux/usb.h
+++ b/include/linux/usb.h
@@ -1209,6 +1209,7 @@ struct usb_anchor {
struct list_head urb_list;
wait_queue_head_t wait;
spinlock_t lock;
+ atomic_t suspend_wakeups;
unsigned int poisoned:1;
};
@@ -1575,6 +1576,8 @@ extern void usb_kill_anchored_urbs(struct usb_anchor *anchor);
extern void usb_poison_anchored_urbs(struct usb_anchor *anchor);
extern void usb_unpoison_anchored_urbs(struct usb_anchor *anchor);
extern void usb_unlink_anchored_urbs(struct usb_anchor *anchor);
+extern void usb_anchor_suspend_wakeups(struct usb_anchor *anchor);
+extern void usb_anchor_resume_wakeups(struct usb_anchor *anchor);
extern void usb_anchor_urb(struct urb *urb, struct usb_anchor *anchor);
extern void usb_unanchor_urb(struct urb *urb);
extern int usb_wait_anchor_empty_timeout(struct usb_anchor *anchor,