1 files changed, 27 insertions, 21 deletions

diff --git a/include/linux/skbuff.h b/include/linux/skbuff.h
index bec1cc7d5e3c..6f69b3f914fb 100644
--- a/include/linux/skbuff.h
+++ b/include/linux/skbuff.h
@@ -1638,6 +1638,11 @@ static inline void skb_set_mac_header(struct sk_buff *skb, const int offset)
         skb->mac_header += offset;
 }
 
+static inline void skb_pop_mac_header(struct sk_buff *skb)
+{
+        skb->mac_header = skb->network_header;
+}
+
 static inline void skb_probe_transport_header(struct sk_buff *skb,
                                               const int offset_hint)
 {
@@ -2263,6 +2268,24 @@ static inline void skb_postpull_rcsum(struct sk_buff *skb,
 
 unsigned char *skb_pull_rcsum(struct sk_buff *skb, unsigned int len);
 
+/**
+ *      pskb_trim_rcsum - trim received skb and update checksum
+ *      @skb: buffer to trim
+ *      @len: new length
+ *
+ *      This is exactly the same as pskb_trim except that it ensures the
+ *      checksum of received packets are still valid after the operation.
+ */
+
+static inline int pskb_trim_rcsum(struct sk_buff *skb, unsigned int len)
+{
+        if (likely(len >= skb->len))
+                return 0;
+        if (skb->ip_summed == CHECKSUM_COMPLETE)
+                skb->ip_summed = CHECKSUM_NONE;
+        return __pskb_trim(skb, len);
+}
+
 #define skb_queue_walk(queue, skb) \
                 for (skb = (queue)->next;                                       \
                      skb != (struct sk_buff *)(queue);                          \
@@ -2360,27 +2383,6 @@ __wsum __skb_checksum(const struct sk_buff *skb, int offset, int len,
 __wsum skb_checksum(const struct sk_buff *skb, int offset, int len,
                     __wsum csum);
 
-/**
- *      pskb_trim_rcsum - trim received skb and update checksum
- *      @skb: buffer to trim
- *      @len: new length
- *
- *      This is exactly the same as pskb_trim except that it ensures the
- *      checksum of received packets are still valid after the operation.
- */
-
-static inline int pskb_trim_rcsum(struct sk_buff *skb, unsigned int len)
-{
-        if (likely(len >= skb->len))
-                return 0;
-        if (skb->ip_summed == CHECKSUM_COMPLETE) {
-                __wsum adj = skb_checksum(skb, len, skb->len - len, 0);
-
-                skb->csum = csum_sub(skb->csum, adj);
-        }
-        return __pskb_trim(skb, len);
-}
-
 static inline void *skb_header_pointer(const struct sk_buff *skb, int offset,
                                        int len, void *buffer)
 {
@@ -2529,6 +2531,10 @@ static inline void sw_tx_timestamp(struct sk_buff *skb)
  * Ethernet MAC Drivers should call this function in their hard_xmit()
  * function immediately before giving the sk_buff to the MAC hardware.
  *
+ * Specifically, one should make absolutely sure that this function is
+ * called before TX completion of this packet can trigger.  Otherwise
+ * the packet could potentially already be freed.
+ *
  * @skb: A socket buffer.
  */
 static inline void skb_tx_timestamp(struct sk_buff *skb)