4 files changed, 33 insertions, 29 deletions

diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h
index dfc1d8b8bd0f..456eb1fe51e8 100644
--- a/include/linux/netdevice.h
+++ b/include/linux/netdevice.h
@@ -1883,8 +1883,8 @@ struct napi_gro_cb {
         /* GRO checksum is valid */
         u8      csum_valid:1;
 
-        /* Number encapsulation layers crossed */
-        u8      encapsulation;
+        /* Number of checksums via CHECKSUM_UNNECESSARY */
+        u8      csum_cnt:3;
 
         /* used to support CHECKSUM_COMPLETE for tunneling protocols */
         __wsum  csum;
@@ -2179,8 +2179,7 @@ static inline bool __skb_gro_checksum_validate_needed(struct sk_buff *skb,
                                                       __sum16 check)
 {
         return (skb->ip_summed != CHECKSUM_PARTIAL &&
-                (skb->ip_summed != CHECKSUM_UNNECESSARY ||
-                 (NAPI_GRO_CB(skb)->encapsulation > skb->encapsulation)) &&
+                NAPI_GRO_CB(skb)->csum_cnt == 0 &&
                 (!zero_okay || check));
 }
 
@@ -2196,18 +2195,17 @@ static inline __sum16 __skb_gro_checksum_validate_complete(struct sk_buff *skb,
         return __skb_gro_checksum_complete(skb);
 }
 
-/* Update skb for CHECKSUM_UNNECESSARY when we verified a top level
- * checksum or an encapsulated one during GRO. This saves work
- * if we fallback to normal path with the packet.
- */
 static inline void skb_gro_incr_csum_unnecessary(struct sk_buff *skb)
 {
-        if (skb->ip_summed == CHECKSUM_UNNECESSARY) {
-                if (NAPI_GRO_CB(skb)->encapsulation)
-                        skb->encapsulation = 1;
-        } else if (skb->ip_summed != CHECKSUM_PARTIAL) {
-                skb->ip_summed = CHECKSUM_UNNECESSARY;
-                skb->encapsulation = 0;
+        if (NAPI_GRO_CB(skb)->csum_cnt > 0) {
+                /* Consume a checksum from CHECKSUM_UNNECESSARY */
+                NAPI_GRO_CB(skb)->csum_cnt--;
+        } else {
+                /* Update skb for CHECKSUM_UNNECESSARY and csum_level when we
+                 * verified a new top level checksum or an encapsulated one
+                 * during GRO. This saves work if we fallback to normal path.
+                 */
+                __skb_incr_checksum_unnecessary(skb);
         }
 }
 
diff --git a/net/core/dev.c b/net/core/dev.c
index 26d296c2447c..a6077ef56345 100644
--- a/net/core/dev.c
+++ b/net/core/dev.c
@@ -3962,13 +3962,6 @@ static enum gro_result dev_gro_receive(struct napi_struct *napi, struct sk_buff
 
         gro_list_prepare(napi, skb);
 
-        if (skb->ip_summed == CHECKSUM_COMPLETE) {
-                NAPI_GRO_CB(skb)->csum = skb->csum;
-                NAPI_GRO_CB(skb)->csum_valid = 1;
-        } else {
-                NAPI_GRO_CB(skb)->csum_valid = 0;
-        }
-
         rcu_read_lock();
         list_for_each_entry_rcu(ptype, head, list) {
                 if (ptype->type != type || !ptype->callbacks.gro_receive)
@@ -3980,7 +3973,22 @@ static enum gro_result dev_gro_receive(struct napi_struct *napi, struct sk_buff
                 NAPI_GRO_CB(skb)->flush = 0;
                 NAPI_GRO_CB(skb)->free = 0;
                 NAPI_GRO_CB(skb)->udp_mark = 0;
-                NAPI_GRO_CB(skb)->encapsulation = 0;
+
+                /* Setup for GRO checksum validation */
+                switch (skb->ip_summed) {
+                case CHECKSUM_COMPLETE:
+                        NAPI_GRO_CB(skb)->csum = skb->csum;
+                        NAPI_GRO_CB(skb)->csum_valid = 1;
+                        NAPI_GRO_CB(skb)->csum_cnt = 0;
+                        break;
+                case CHECKSUM_UNNECESSARY:
+                        NAPI_GRO_CB(skb)->csum_cnt = skb->csum_level + 1;
+                        NAPI_GRO_CB(skb)->csum_valid = 0;
+                        break;
+                default:
+                        NAPI_GRO_CB(skb)->csum_cnt = 0;
+                        NAPI_GRO_CB(skb)->csum_valid = 0;
+                }
 
                 pp = ptype->callbacks.gro_receive(&napi->gro_list, skb);
                 break;
diff --git a/net/ipv4/gre_offload.c b/net/ipv4/gre_offload.c
index d1bd16937d93..a4d7965fb880 100644
--- a/net/ipv4/gre_offload.c
+++ b/net/ipv4/gre_offload.c
@@ -172,12 +172,9 @@ static struct sk_buff **gre_gro_receive(struct sk_buff **head,
         }
 
         /* Don't bother verifying checksum if we're going to flush anyway. */
-        if (greh->flags & GRE_CSUM) {
-                if (!NAPI_GRO_CB(skb)->flush &&
-                    skb_gro_checksum_simple_validate(skb))
+        if ((greh->flags & GRE_CSUM) && !NAPI_GRO_CB(skb)->flush &&
+            skb_gro_checksum_simple_validate(skb))
                         goto out_unlock;
-                NAPI_GRO_CB(skb)->encapsulation++;
-        }
 
         flush = 0;
 
diff --git a/net/ipv4/udp_offload.c b/net/ipv4/udp_offload.c
index 8ed460e3753c..a6adff98382a 100644
--- a/net/ipv4/udp_offload.c
+++ b/net/ipv4/udp_offload.c
@@ -238,12 +238,13 @@ struct sk_buff **udp_gro_receive(struct sk_buff **head, struct sk_buff *skb,
         int flush = 1;
 
         if (NAPI_GRO_CB(skb)->udp_mark ||
-            (!skb->encapsulation && !NAPI_GRO_CB(skb)->csum_valid))
+            (skb->ip_summed != CHECKSUM_PARTIAL &&
+             NAPI_GRO_CB(skb)->csum_cnt == 0 &&
+             !NAPI_GRO_CB(skb)->csum_valid))
                 goto out;
 
         /* mark that this skb passed once through the udp gro layer */
         NAPI_GRO_CB(skb)->udp_mark = 1;
-        NAPI_GRO_CB(skb)->encapsulation++;
 
         rcu_read_lock();
         uo_priv = rcu_dereference(udp_offload_base);