USB: anchor API changes needed for btusb

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From: Linux Kernel Mailing List
Date: Friday, October 17, 2008 - 5:05 pm

Gitweb:     http://git.kernel.org/git/?p=linux/kernel/git/torvalds/linux-2.6.git;a=commit;h=198762...
Commit:     1987625226a918cd20c334ffce5e2a224cba0718
Parent:     c0f082c5367a02e8493d779e16ad336167e14718
Author:     Oliver Neukum <oliver@neukum.org>
AuthorDate: Mon Aug 25 22:40:25 2008 +0200
Committer:  Greg Kroah-Hartman <gregkh@suse.de>
CommitDate: Fri Oct 17 14:41:02 2008 -0700

    USB: anchor API changes needed for btusb
    
    This extends the anchor API as btusb needs for autosuspend.
    
    
    Signed-off-by: Oliver Neukum <oneukum@suse.de>
    Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
---
 drivers/usb/core/urb.c |   70 ++++++++++++++++++++++++++++++++++++++++++++++++
 include/linux/usb.h    |    3 ++
 2 files changed, 73 insertions(+), 0 deletions(-)

diff --git a/drivers/usb/core/urb.c b/drivers/usb/core/urb.c
index eebc070..175d528 100644
--- a/drivers/usb/core/urb.c
+++ b/drivers/usb/core/urb.c
@@ -716,3 +716,73 @@ int usb_wait_anchor_empty_timeout(struct usb_anchor *anchor,
 				  msecs_to_jiffies(timeout));
 }
 EXPORT_SYMBOL_GPL(usb_wait_anchor_empty_timeout);
+
+/**
+ * usb_get_from_anchor - get an anchor's oldest urb
+ * @anchor: the anchor whose urb you want
+ *
+ * this will take the oldest urb from an anchor,
+ * unanchor and return it
+ */
+struct urb *usb_get_from_anchor(struct usb_anchor *anchor)
+{
+	struct urb *victim;
+	unsigned long flags;
+
+	spin_lock_irqsave(&anchor->lock, flags);
+	if (!list_empty(&anchor->urb_list)) {
+		victim = list_entry(anchor->urb_list.next, struct urb,
+				    anchor_list);
+		usb_get_urb(victim);
+		spin_unlock_irqrestore(&anchor->lock, flags);
+		usb_unanchor_urb(victim);
+	} else {
+		spin_unlock_irqrestore(&anchor->lock, flags);
+		victim = NULL;
+	}
+
+	return victim;
+}
+
+EXPORT_SYMBOL_GPL(usb_get_from_anchor);
+
+/**
+ * usb_scuttle_anchored_urbs - unanchor all an anchor's urbs
+ * @anchor: the anchor whose urbs you want to unanchor
+ *
+ * use this to get rid of all an anchor's urbs
+ */
+void usb_scuttle_anchored_urbs(struct usb_anchor *anchor)
+{
+	struct urb *victim;
+	unsigned long flags;
+
+	spin_lock_irqsave(&anchor->lock, flags);
+	while (!list_empty(&anchor->urb_list)) {
+		victim = list_entry(anchor->urb_list.prev, struct urb,
+				    anchor_list);
+		usb_get_urb(victim);
+		spin_unlock_irqrestore(&anchor->lock, flags);
+		/* this may free the URB */
+		usb_unanchor_urb(victim);
+		usb_put_urb(victim);
+		spin_lock_irqsave(&anchor->lock, flags);
+	}
+	spin_unlock_irqrestore(&anchor->lock, flags);
+}
+
+EXPORT_SYMBOL_GPL(usb_scuttle_anchored_urbs);
+
+/**
+ * usb_anchor_empty - is an anchor empty
+ * @anchor: the anchor you want to query
+ *
+ * returns 1 if the anchor has no urbs associated with it
+ */
+int usb_anchor_empty(struct usb_anchor *anchor)
+{
+	return list_empty(&anchor->urb_list);
+}
+
+EXPORT_SYMBOL_GPL(usb_anchor_empty);
+
diff --git a/include/linux/usb.h b/include/linux/usb.h
index d979279..8fa973b 100644
--- a/include/linux/usb.h
+++ b/include/linux/usb.h
@@ -1469,6 +1469,9 @@ 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,
 					 unsigned int timeout);
+extern struct urb *usb_get_from_anchor(struct usb_anchor *anchor);
+extern void usb_scuttle_anchored_urbs(struct usb_anchor *anchor);
+extern int usb_anchor_empty(struct usb_anchor *anchor);
 
 /**
  * usb_urb_dir_in - check if an URB describes an IN transfer
--
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