2 files changed, 13 insertions, 0 deletions

diff --git a/drivers/net/ppp/ppp_generic.c b/drivers/net/ppp/ppp_generic.c
index af034dba9bd6..9d15566521a7 100644
--- a/drivers/net/ppp/ppp_generic.c
+++ b/drivers/net/ppp/ppp_generic.c
@@ -1716,6 +1716,7 @@ ppp_receive_frame(struct ppp *ppp, struct sk_buff *skb, struct channel *pch)
 {
         /* note: a 0-length skb is used as an error indication */
         if (skb->len > 0) {
+                skb_checksum_complete_unset(skb);
 #ifdef CONFIG_PPP_MULTILINK
                 /* XXX do channel-level decompression here */
                 if (PPP_PROTO(skb) == PPP_MP)
diff --git a/include/linux/skbuff.h b/include/linux/skbuff.h
index 0991259643d6..06793b598f44 100644
--- a/include/linux/skbuff.h
+++ b/include/linux/skbuff.h
@@ -3016,6 +3016,18 @@ static inline bool __skb_checksum_validate_needed(struct sk_buff *skb,
  */
 #define CHECKSUM_BREAK 76
 
+/* Unset checksum-complete
+ *
+ * Unset checksum complete can be done when packet is being modified
+ * (uncompressed for instance) and checksum-complete value is
+ * invalidated.
+ */
+static inline void skb_checksum_complete_unset(struct sk_buff *skb)
+{
+        if (skb->ip_summed == CHECKSUM_COMPLETE)
+                skb->ip_summed = CHECKSUM_NONE;
+}
+
 /* Validate (init) checksum based on checksum complete.
  *
  * Return values: