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

It is enough to protect accesses to reject field of urb
by marking it as atomic_t,also it is the only reason of
existence of usb_reject_lock,so remove the lock to make
code more clean.
Signed-off-by: Ming Lei <tom.leiming@gmail.com>
Acked-off-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

drivers/usb/core/hcd.c

@@ -1010,7 +1010,7 @@ int usb_hcd_link_urb_to_ep(struct usb_hcd *hcd, struct urb *urb)
 	spin_lock(&hcd_urb_list_lock);
 
 	/* Check that the URB isn't being killed */
-	if (unlikely(urb->reject)) {
+	if (unlikely(atomic_read(&urb->reject))) {
 		rc = -EPERM;
 		goto done;
 	}
@@ -1340,7 +1340,7 @@ int usb_hcd_submit_urb (struct urb *urb, gfp_t mem_flags)
 		INIT_LIST_HEAD(&urb->urb_list);
 		atomic_dec(&urb->use_count);
 		atomic_dec(&urb->dev->urbnum);
-		if (urb->reject)
+		if (atomic_read(&urb->reject))
 			wake_up(&usb_kill_urb_queue);
 		usb_put_urb(urb);
 	}
@@ -1444,7 +1444,7 @@ void usb_hcd_giveback_urb(struct usb_hcd *hcd, struct urb *urb, int status)
 	urb->status = status;
 	urb->complete (urb);
 	atomic_dec (&urb->use_count);
-	if (unlikely (urb->reject))
+	if (unlikely(atomic_read(&urb->reject)))
 		wake_up (&usb_kill_urb_queue);
 	usb_put_urb (urb);
 }

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)
 {
@@ -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);
@@ -565,16 +562,12 @@ 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);
 
@@ -606,9 +599,7 @@ 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);
@@ -617,14 +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);
 

include/linux/usb.h

@@ -1340,7 +1340,7 @@ struct urb {
 	struct kref kref;		/* reference count of the URB */
 	void *hcpriv;			/* private data for host controller */
 	atomic_t use_count;		/* concurrent submissions counter */
-	u8 reject;			/* submissions will fail */
+	atomic_t reject;		/* submissions will fail */
 	int unlinked;			/* unlink error code */
 
 	/* public: documented fields in the urb that can be used by drivers */