xfrm: Mark flowi arg to ->get_tos() const.

Signed-off-by: NDavid S. Miller <davem@davemloft.net>

include/net/xfrm.h

@@ -273,7 +273,7 @@ struct xfrm_policy_afinfo {
 	void			(*decode_session)(struct sk_buff *skb,
 						  struct flowi *fl,
 						  int reverse);
-	int			(*get_tos)(struct flowi *fl);
+	int			(*get_tos)(const struct flowi *fl);
 	int			(*init_path)(struct xfrm_dst *path,
 					     struct dst_entry *dst,
 					     int nfheader_len);

net/ipv4/xfrm4_policy.c

@@ -56,7 +56,7 @@ static int xfrm4_get_saddr(struct net *net,
 	return 0;
 }
 
-static int xfrm4_get_tos(struct flowi *fl)
+static int xfrm4_get_tos(const struct flowi *fl)
 {
 	return IPTOS_RT_MASK & fl->fl4_tos; /* Strip ECN bits */
 }

net/ipv6/xfrm6_policy.c

@@ -67,7 +67,7 @@ static int xfrm6_get_saddr(struct net *net,
 	return 0;
 }
 
-static int xfrm6_get_tos(struct flowi *fl)
+static int xfrm6_get_tos(const struct flowi *fl)
 {
 	return 0;
 }

net/xfrm/xfrm_policy.c

@@ -1256,7 +1256,7 @@ xfrm_tmpl_resolve(struct xfrm_policy **pols, int npols, struct flowi *fl,
  * still valid.
  */
 
-static inline int xfrm_get_tos(struct flowi *fl, int family)
+static inline int xfrm_get_tos(const struct flowi *fl, int family)
 {
 	struct xfrm_policy_afinfo *afinfo = xfrm_policy_get_afinfo(family);
 	int tos;