USB: mark "reject" field of struct urb as atomic_t

[linux-2.6-omap-h63xx.git] / drivers / usb / core / urb.c

diff --git a/drivers/usb/core/urb.c b/drivers/usb/core/urb.c
index f2638009a4648414892179c3fae7d105f73d4c03..b5e9948698bfcdbc20bc0f7f93e293069d04272d 100644 (file)
--- a/drivers/usb/core/urb.c
+++ b/drivers/usb/core/urb.c
@@ -10,7 +10,6 @@
 
 #define to_urb(d) container_of(d, struct urb, kref)
 
-static DEFINE_SPINLOCK(usb_reject_lock);
 
 static void urb_destroy(struct kref *kref)
 {
@@ -85,8 +84,8 @@ EXPORT_SYMBOL_GPL(usb_alloc_urb);
  * Must be called when a user of a urb is finished with it.  When the last user
  * of the urb calls this function, the memory of the urb is freed.
  *
- * Note: The transfer buffer associated with the urb is not freed, that must be
- * done elsewhere.
+ * Note: The transfer buffer associated with the urb is not freed unless the
+ * URB_FREE_BUFFER transfer flag is set.
  */
 void usb_free_urb(struct urb *urb)
 {
@@ -131,9 +130,7 @@ void usb_anchor_urb(struct urb *urb, struct usb_anchor *anchor)
        urb->anchor = anchor;
 
        if (unlikely(anchor->poisoned)) {
-               spin_lock(&usb_reject_lock);
-               urb->reject++;
-               spin_unlock(&usb_reject_lock);
+               atomic_inc(&urb->reject);
        }
 
        spin_unlock_irqrestore(&anchor->lock, flags);
@@ -474,6 +471,12 @@ EXPORT_SYMBOL_GPL(usb_submit_urb);
  * indicating that the request has been canceled (rather than any other
  * code).
  *
+ * Drivers should not call this routine or related routines, such as
+ * usb_kill_urb() or usb_unlink_anchored_urbs(), after their disconnect
+ * method has returned.  The disconnect function should synchronize with
+ * a driver's I/O routines to insure that all URB-related activity has
+ * completed before it returns.
+ *
  * This request is always asynchronous.  Success is indicated by
  * returning -EINPROGRESS, at which time the URB will probably not yet
  * have been given back to the device driver.  When it is eventually
@@ -550,22 +553,21 @@ EXPORT_SYMBOL_GPL(usb_unlink_urb);
  * This routine may not be used in an interrupt context (such as a bottom
  * half or a completion handler), or when holding a spinlock, or in other
  * situations where the caller can't schedule().
+ *
+ * This routine should not be called by a driver after its disconnect
+ * method has returned.
  */
 void usb_kill_urb(struct urb *urb)
 {
        might_sleep();
        if (!(urb && urb->dev && urb->ep))
                return;
-       spin_lock_irq(&usb_reject_lock);
-       ++urb->reject;
-       spin_unlock_irq(&usb_reject_lock);
+       atomic_inc(&urb->reject);
 
        usb_hcd_unlink_urb(urb, -ENOENT);
        wait_event(usb_kill_urb_queue, atomic_read(&urb->use_count) == 0);
 
-       spin_lock_irq(&usb_reject_lock);
-       --urb->reject;
-       spin_unlock_irq(&usb_reject_lock);
+       atomic_dec(&urb->reject);
 }
 EXPORT_SYMBOL_GPL(usb_kill_urb);
 
@@ -588,15 +590,16 @@ EXPORT_SYMBOL_GPL(usb_kill_urb);
  * This routine may not be used in an interrupt context (such as a bottom
  * half or a completion handler), or when holding a spinlock, or in other
  * situations where the caller can't schedule().
+ *
+ * This routine should not be called by a driver after its disconnect
+ * method has returned.
  */
 void usb_poison_urb(struct urb *urb)
 {
        might_sleep();
        if (!(urb && urb->dev && urb->ep))
                return;
-       spin_lock_irq(&usb_reject_lock);
-       ++urb->reject;
-       spin_unlock_irq(&usb_reject_lock);
+       atomic_inc(&urb->reject);
 
        usb_hcd_unlink_urb(urb, -ENOENT);
        wait_event(usb_kill_urb_queue, atomic_read(&urb->use_count) == 0);
@@ -605,14 +608,10 @@ EXPORT_SYMBOL_GPL(usb_poison_urb);
 
 void usb_unpoison_urb(struct urb *urb)
 {
-       unsigned long flags;
-
        if (!urb)
                return;
 
-       spin_lock_irqsave(&usb_reject_lock, flags);
-       --urb->reject;
-       spin_unlock_irqrestore(&usb_reject_lock, flags);
+       atomic_dec(&urb->reject);
 }
 EXPORT_SYMBOL_GPL(usb_unpoison_urb);
 
@@ -622,6 +621,9 @@ EXPORT_SYMBOL_GPL(usb_unpoison_urb);
  *
  * this allows all outstanding URBs to be killed starting
  * from the back of the queue
+ *
+ * This routine should not be called by a driver after its disconnect
+ * method has returned.
  */
 void usb_kill_anchored_urbs(struct usb_anchor *anchor)
 {
@@ -651,6 +653,9 @@ EXPORT_SYMBOL_GPL(usb_kill_anchored_urbs);
  * this allows all outstanding URBs to be poisoned starting
  * from the back of the queue. Newly added URBs will also be
  * poisoned
+ *
+ * This routine should not be called by a driver after its disconnect
+ * method has returned.
  */
 void usb_poison_anchored_urbs(struct usb_anchor *anchor)
 {
@@ -672,6 +677,7 @@ void usb_poison_anchored_urbs(struct usb_anchor *anchor)
        spin_unlock_irq(&anchor->lock);
 }
 EXPORT_SYMBOL_GPL(usb_poison_anchored_urbs);
+
 /**
  * usb_unlink_anchored_urbs - asynchronously cancel transfer requests en masse
  * @anchor: anchor the requests are bound to
@@ -680,6 +686,9 @@ EXPORT_SYMBOL_GPL(usb_poison_anchored_urbs);
  * from the back of the queue. This function is asynchronous.
  * The unlinking is just tiggered. It may happen after this
  * function has returned.
+ *
+ * This routine should not be called by a driver after its disconnect
+ * method has returned.
  */
 void usb_unlink_anchored_urbs(struct usb_anchor *anchor)
 {