[NET]: Warn in __skb_trim if skb is paged

It's better to warn and fail rather than rarely triggering BUG on paths
that incorrectly call skb_trim/__skb_trim on a non-linear skb.

Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 2 insertions, 5 deletions

diff --git a/net/core/skbuff.c b/net/core/skbuff.c
index 96cdcbe24ba2..bb7210f4005e 100644
--- a/net/core/skbuff.c
+++ b/net/core/skbuff.c
@@ -801,12 +801,10 @@ struct sk_buff *skb_pad(struct sk_buff *skb, int pad)
         return nskb;
 }       
  
-/* Trims skb to length len. It can change skb pointers, if "realloc" is 1.
- * If realloc==0 and trimming is impossible without change of data,
- * it is BUG().
+/* Trims skb to length len. It can change skb pointers.
  */
 
-int ___pskb_trim(struct sk_buff *skb, unsigned int len, int realloc)
+int ___pskb_trim(struct sk_buff *skb, unsigned int len)
 {
         int offset = skb_headlen(skb);
         int nfrags = skb_shinfo(skb)->nr_frags;
@@ -816,7 +814,6 @@ int ___pskb_trim(struct sk_buff *skb, unsigned int len, int realloc)
                 int end = offset + skb_shinfo(skb)->frags[i].size;
                 if (end > len) {
                         if (skb_cloned(skb)) {
-                                BUG_ON(!realloc);
                                 if (pskb_expand_head(skb, 0, 0, GFP_ATOMIC))
                                         return -ENOMEM;
                         }