fib: introduce FIB info offload flag helpers

These helpers are to be used in case someone offloads the FIB entry. The
result is that if the entry is offloaded to at least one device, the
offload flag is set.
Signed-off-by: Jiri Pirko <jiri@mellanox.com>
Reviewed-by: Ido Schimmel <idosch@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

include/net/ip_fib.h

@@ -123,6 +123,7 @@ struct fib_info {
 #ifdef CONFIG_IP_ROUTE_MULTIPATH
 	int			fib_weight;
 #endif
+	unsigned int		fib_offload_cnt;
 	struct rcu_head		rcu;
 	struct fib_nh		fib_nh[0];
 #define fib_dev		fib_nh[0].nh_dev
@@ -174,6 +175,18 @@ struct fib_result_nl {
 
 __be32 fib_info_update_nh_saddr(struct net *net, struct fib_nh *nh);
 
+static inline void fib_info_offload_inc(struct fib_info *fi)
+{
+	fi->fib_offload_cnt++;
+	fi->fib_flags |= RTNH_F_OFFLOAD;
+}
+
+static inline void fib_info_offload_dec(struct fib_info *fi)
+{
+	if (--fi->fib_offload_cnt == 0)
+		fi->fib_flags &= ~RTNH_F_OFFLOAD;
+}
+
 #define FIB_RES_SADDR(net, res)				\
 	((FIB_RES_NH(res).nh_saddr_genid ==		\
 	  atomic_read(&(net)->ipv4.dev_addr_genid)) ?	\

net/switchdev/switchdev.c

@@ -1216,7 +1216,7 @@ int switchdev_fib_ipv4_add(u32 dst, int dst_len, struct fib_info *fi,
 	ipv4_fib.obj.orig_dev = dev;
 	err = switchdev_port_obj_add(dev, &ipv4_fib.obj);
 	if (!err)
-		fi->fib_flags |= RTNH_F_OFFLOAD;
+		fib_info_offload_inc(fi);
 
 	return err == -EOPNOTSUPP ? 0 : err;
 }
@@ -1260,7 +1260,7 @@ int switchdev_fib_ipv4_del(u32 dst, int dst_len, struct fib_info *fi,
 	ipv4_fib.obj.orig_dev = dev;
 	err = switchdev_port_obj_del(dev, &ipv4_fib.obj);
 	if (!err)
-		fi->fib_flags &= ~RTNH_F_OFFLOAD;
+		fib_info_offload_dec(fi);
 
 	return err == -EOPNOTSUPP ? 0 : err;
 }