vxlan: Remove access to nexthop group struct

vxlan driver should be using helpers to access nexthop struct
internals. Remove open check if whether nexthop is multipath in
favor of the existing nexthop_is_multipath helper. Add a new
helper, nexthop_has_v4, to cover the need to check has_v4 in
a group.

Fixes: 1274e1cc ("vxlan: ecmp support for mac fdb entries")
Cc: Roopa Prabhu <roopa@cumulusnetworks.com>
Signed-off-by: David Ahern <dsahern@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/vxlan.c

@@ -857,7 +857,6 @@ static int vxlan_fdb_nh_update(struct vxlan_dev *vxlan, struct vxlan_fdb *fdb,
 			       u32 nhid, struct netlink_ext_ack *extack)
 {
 	struct nexthop *old_nh = rtnl_dereference(fdb->nh);
-	struct nh_group *nhg;
 	struct nexthop *nh;
 	int err = -EINVAL;
 
@@ -881,8 +880,7 @@ static int vxlan_fdb_nh_update(struct vxlan_dev *vxlan, struct vxlan_fdb *fdb,
 			goto err_inval;
 		}
 
-		nhg = rtnl_dereference(nh->nh_grp);
-		if (!nh->is_group || !nhg->mpath) {
+		if (!nexthop_is_multipath(nh)) {
 			NL_SET_ERR_MSG(extack, "Nexthop is not a multipath group");
 			goto err_inval;
 		}
@@ -890,14 +888,14 @@ static int vxlan_fdb_nh_update(struct vxlan_dev *vxlan, struct vxlan_fdb *fdb,
 		/* check nexthop group family */
 		switch (vxlan->default_dst.remote_ip.sa.sa_family) {
 		case AF_INET:
-			if (!nhg->has_v4) {
+			if (!nexthop_has_v4(nh)) {
 				err = -EAFNOSUPPORT;
 				NL_SET_ERR_MSG(extack, "Nexthop group family not supported");
 				goto err_inval;
 			}
 			break;
 		case AF_INET6:
-			if (nhg->has_v4) {
+			if (nexthop_has_v4(nh)) {
 				err = -EAFNOSUPPORT;
 				NL_SET_ERR_MSG(extack, "Nexthop group family not supported");
 				goto err_inval;

include/net/nexthop.h

@@ -151,6 +151,17 @@ static inline bool nexthop_is_fdb(const struct nexthop *nh)
 	}
 }
 
+static inline bool nexthop_has_v4(const struct nexthop *nh)
+{
+	if (nh->is_group) {
+		struct nh_group *nh_grp;
+
+		nh_grp = rcu_dereference_rtnl(nh->nh_grp);
+		return nh_grp->has_v4;
+	}
+	return false;
+}
+
 static inline bool nexthop_is_multipath(const struct nexthop *nh)
 {
 	if (nh->is_group) {