net: Add safe reverse SKB queue walkers.

Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/include/linux/skbuff.h b/include/linux/skbuff.h
index bf221d65d9ad5d0c2878795021b2733012c4ef2f..6e946da9d1d65cbf6cd4acd25159e9a7188e85ce 100644 (file)
--- a/include/linux/skbuff.h
+++ b/include/linux/skbuff.h
@@ -1801,6 +1801,15 @@ static inline int pskb_trim_rcsum(struct sk_buff *skb, unsigned int len)
                     prefetch(skb->prev), (skb != (struct sk_buff *)(queue));   \
                     skb = skb->prev)
 
+#define skb_queue_reverse_walk_safe(queue, skb, tmp)                           \
+               for (skb = (queue)->prev, tmp = skb->prev;                      \
+                    skb != (struct sk_buff *)(queue);                          \
+                    skb = tmp, tmp = skb->prev)
+
+#define skb_queue_reverse_walk_from_safe(queue, skb, tmp)                      \
+               for (tmp = skb->prev;                                           \
+                    skb != (struct sk_buff *)(queue);                          \
+                    skb = tmp, tmp = skb->prev)
 
 static inline bool skb_has_frag_list(const struct sk_buff *skb)
 {