diff options
| -rw-r--r-- | drivers/bluetooth/hci_usb.h | 21 |
1 files changed, 13 insertions, 8 deletions
diff --git a/drivers/bluetooth/hci_usb.h b/drivers/bluetooth/hci_usb.h index 414080a..1790cc8 100644 --- a/drivers/bluetooth/hci_usb.h +++ b/drivers/bluetooth/hci_usb.h @@ -70,7 +70,8 @@ static inline void _urb_queue_head(struct _urb_queue *q, struct _urb *_urb) { unsigned long flags; spin_lock_irqsave(&q->lock, flags); - list_add(&_urb->list, &q->head); _urb->queue = q; + /* _urb_unlink needs to know which spinlock to use, thus mb(). */ + _urb->queue = q; mb(); list_add(&_urb->list, &q->head); spin_unlock_irqrestore(&q->lock, flags); } @@ -78,19 +79,23 @@ static inline void _urb_queue_tail(struct _urb_queue *q, struct _urb *_urb) { unsigned long flags; spin_lock_irqsave(&q->lock, flags); - list_add_tail(&_urb->list, &q->head); _urb->queue = q; + /* _urb_unlink needs to know which spinlock to use, thus mb(). */ + _urb->queue = q; mb(); list_add_tail(&_urb->list, &q->head); spin_unlock_irqrestore(&q->lock, flags); } static inline void _urb_unlink(struct _urb *_urb) { - struct _urb_queue *q = _urb->queue; + struct _urb_queue *q; unsigned long flags; - if (q) { - spin_lock_irqsave(&q->lock, flags); - list_del(&_urb->list); _urb->queue = NULL; - spin_unlock_irqrestore(&q->lock, flags); - } + + mb(); + q = _urb->queue; + /* If q is NULL, it will die at easy-to-debug NULL pointer dereference. + No need to BUG(). */ + spin_lock_irqsave(&q->lock, flags); + list_del(&_urb->list); _urb->queue = NULL; + spin_unlock_irqrestore(&q->lock, flags); } struct hci_usb { |
