diff options
| -rw-r--r-- | net/atm/ipcommon.c | 17 |
1 files changed, 11 insertions, 6 deletions
diff --git a/net/atm/ipcommon.c b/net/atm/ipcommon.c index 4b1faca5013..1d3de42fada 100644 --- a/net/atm/ipcommon.c +++ b/net/atm/ipcommon.c @@ -25,22 +25,27 @@ /* * skb_migrate appends the list at "from" to "to", emptying "from" in the * process. skb_migrate is atomic with respect to all other skb operations on - * "from" and "to". Note that it locks both lists at the same time, so beware - * of potential deadlocks. + * "from" and "to". Note that it locks both lists at the same time, so to deal + * with the lock ordering, the locks are taken in address order. * * This function should live in skbuff.c or skbuff.h. */ -void skb_migrate(struct sk_buff_head *from,struct sk_buff_head *to) +void skb_migrate(struct sk_buff_head *from, struct sk_buff_head *to) { unsigned long flags; struct sk_buff *skb_from = (struct sk_buff *) from; struct sk_buff *skb_to = (struct sk_buff *) to; struct sk_buff *prev; - spin_lock_irqsave(&from->lock,flags); - spin_lock(&to->lock); + if ((unsigned long) from < (unsigned long) to) { + spin_lock_irqsave(&from->lock, flags); + spin_lock_nested(&to->lock, SINGLE_DEPTH_NESTING); + } else { + spin_lock_irqsave(&to->lock, flags); + spin_lock_nested(&from->lock, SINGLE_DEPTH_NESTING); + } prev = from->prev; from->next->prev = to->prev; prev->next = skb_to; @@ -51,7 +56,7 @@ void skb_migrate(struct sk_buff_head *from,struct sk_buff_head *to) from->prev = skb_from; from->next = skb_from; from->qlen = 0; - spin_unlock_irqrestore(&from->lock,flags); + spin_unlock_irqrestore(&from->lock, flags); } |