ip6_gre: Avoid updating tunnel->tun_hlen in __gre6_xmit()

[ Upstream commit f40c064e933d7787ca7411b699504d7a2664c1f5 ]

Do not update tunnel->tun_hlen in data plane code.  Use a local variable
instead, just like "tunnel_hlen" in net/ipv4/ip_gre.c:gre_fb_xmit().

Co-developed-by: Cong Wang <cong.wang@bytedance.com>
Signed-off-by: Cong Wang <cong.wang@bytedance.com>
Signed-off-by: Peilin Ye <peilin.ye@bytedance.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Sasha Levin <sashal@kernel.org>

diff --git a/net/ipv6/ip6_gre.c b/net/ipv6/ip6_gre.c
index 466a561..2887208 100644 (file)
--- a/net/ipv6/ip6_gre.c
+++ b/net/ipv6/ip6_gre.c
@@ -743,6 +743,7 @@ static netdev_tx_t __gre6_xmit(struct sk_buff *skb,
                struct ip_tunnel_info *tun_info;
                const struct ip_tunnel_key *key;
                __be16 flags;
+               int tun_hlen;
 
                tun_info = skb_tunnel_info_txcheck(skb);
                if (IS_ERR(tun_info) ||
@@ -760,9 +761,9 @@ static netdev_tx_t __gre6_xmit(struct sk_buff *skb,
                dsfield = key->tos;
                flags = key->tun_flags &
                        (TUNNEL_CSUM | TUNNEL_KEY | TUNNEL_SEQ);
-               tunnel->tun_hlen = gre_calc_hlen(flags);
+               tun_hlen = gre_calc_hlen(flags);
 
-               gre_build_header(skb, tunnel->tun_hlen,
+               gre_build_header(skb, tun_hlen,
                                 flags, protocol,
                                 tunnel_id_to_key32(tun_info->key.tun_id),
                                 (flags & TUNNEL_SEQ) ? htonl(tunnel->o_seqno++)