From: Tom Herbert <tom@herbertland.com>
Date: Thu, 20 Aug 2015 00:07:32 +0000 (-0700)
Subject: gro: Fix remcsum offload to deal with frags in GRO
X-Git-Tag: omap-for-v4.3/fixes-rc1~110^2~112^2~2
X-Git-Url: http://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=b7fe10e5ebac2a3f37e95535e616494b65fa020f;p=pandora-kernel.git

gro: Fix remcsum offload to deal with frags in GRO

The remote checksum offload GRO did not consider the case that frag0
might be in use. This patch fixes that by accessing headers using the
skb_gro functions and not saving offsets relative to skb->head.

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

diff --git a/drivers/net/vxlan.c b/drivers/net/vxlan.c
index 54615bb9d916..64fcd2402562 100644
--- a/drivers/net/vxlan.c
+++ b/drivers/net/vxlan.c
@@ -519,10 +519,10 @@ static struct vxlanhdr *vxlan_gro_remcsum(struct sk_buff *skb,
 					  u32 data, struct gro_remcsum *grc,
 					  bool nopartial)
 {
-	size_t start, offset, plen;
+	size_t start, offset;
 
 	if (skb->remcsum_offload)
-		return NULL;
+		return vh;
 
 	if (!NAPI_GRO_CB(skb)->csum_valid)
 		return NULL;
@@ -532,17 +532,8 @@ static struct vxlanhdr *vxlan_gro_remcsum(struct sk_buff *skb,
 			  offsetof(struct udphdr, check) :
 			  offsetof(struct tcphdr, check));
 
-	plen = hdrlen + offset + sizeof(u16);
-
-	/* Pull checksum that will be written */
-	if (skb_gro_header_hard(skb, off + plen)) {
-		vh = skb_gro_header_slow(skb, off + plen, off);
-		if (!vh)
-			return NULL;
-	}
-
-	skb_gro_remcsum_process(skb, (void *)vh + hdrlen,
-				start, offset, grc, nopartial);
+	vh = skb_gro_remcsum_process(skb, (void *)vh, off, hdrlen,
+				     start, offset, grc, nopartial);
 
 	skb->remcsum_offload = 1;
 
@@ -573,7 +564,6 @@ static struct sk_buff **vxlan_gro_receive(struct sk_buff **head,
 			goto out;
 	}
 
-	skb_gro_pull(skb, sizeof(struct vxlanhdr)); /* pull vxlan header */
 	skb_gro_postpull_rcsum(skb, vh, sizeof(struct vxlanhdr));
 
 	flags = ntohl(vh->vx_flags);
@@ -588,6 +578,8 @@ static struct sk_buff **vxlan_gro_receive(struct sk_buff **head,
 			goto out;
 	}
 
+	skb_gro_pull(skb, sizeof(struct vxlanhdr)); /* pull vxlan header */
+
 	flush = 0;
 
 	for (p = *head; p; p = p->next) {
@@ -1110,6 +1102,9 @@ static struct vxlanhdr *vxlan_remcsum(struct sk_buff *skb, struct vxlanhdr *vh,
 {
 	size_t start, offset, plen;
 
+	if (skb->remcsum_offload)
+		return vh;
+
 	start = (data & VXLAN_RCO_MASK) << VXLAN_RCO_SHIFT;
 	offset = start + ((data & VXLAN_RCO_UDP) ?
 			  offsetof(struct udphdr, check) :
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