net: add skb functions to process remote checksum offload

This patch adds skb_remcsum_process and skb_gro_remcsum_process to
perform the appropriate adjustments to the skb when receiving
remote checksum offload.

Updated vxlan and gue to use these functions.

Tested: Ran TCP_RR and TCP_STREAM netperf for VXLAN and GUE, did
not see any change in performance.

Signed-off-by: Tom Herbert <therbert@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 2 insertions, 16 deletions

diff --git a/net/ipv4/fou.c b/net/ipv4/fou.c
index 3bc0cf07661c..92ddea1e6457 100644
--- a/net/ipv4/fou.c
+++ b/net/ipv4/fou.c
@@ -70,7 +70,6 @@ static struct guehdr *gue_remcsum(struct sk_buff *skb, struct guehdr *guehdr,
         size_t start = ntohs(pd[0]);
         size_t offset = ntohs(pd[1]);
         size_t plen = hdrlen + max_t(size_t, offset + sizeof(u16), start);
-        __wsum delta;
 
         if (skb->remcsum_offload) {
                 /* Already processed in GRO path */
@@ -82,14 +81,7 @@ static struct guehdr *gue_remcsum(struct sk_buff *skb, struct guehdr *guehdr,
                 return NULL;
         guehdr = (struct guehdr *)&udp_hdr(skb)[1];
 
-        if (unlikely(skb->ip_summed != CHECKSUM_COMPLETE))
-                __skb_checksum_complete(skb);
-
-        delta = remcsum_adjust((void *)guehdr + hdrlen,
-                               skb->csum, start, offset);
-
-        /* Adjust skb->csum since we changed the packet */
-        skb->csum = csum_add(skb->csum, delta);
+        skb_remcsum_process(skb, (void *)guehdr + hdrlen, start, offset);
 
         return guehdr;
 }
@@ -228,7 +220,6 @@ static struct guehdr *gue_gro_remcsum(struct sk_buff *skb, unsigned int off,
         size_t start = ntohs(pd[0]);
         size_t offset = ntohs(pd[1]);
         size_t plen = hdrlen + max_t(size_t, offset + sizeof(u16), start);
-        __wsum delta;
 
         if (skb->remcsum_offload)
                 return guehdr;
@@ -243,12 +234,7 @@ static struct guehdr *gue_gro_remcsum(struct sk_buff *skb, unsigned int off,
                         return NULL;
         }
 
-        delta = remcsum_adjust((void *)guehdr + hdrlen,
-                               NAPI_GRO_CB(skb)->csum, start, offset);
-
-        /* Adjust skb->csum since we changed the packet */
-        skb->csum = csum_add(skb->csum, delta);
-        NAPI_GRO_CB(skb)->csum = csum_add(NAPI_GRO_CB(skb)->csum, delta);
+        skb_gro_remcsum_process(skb, (void *)guehdr + hdrlen, start, offset);
 
         skb->remcsum_offload = 1;