nexthop: Use enum to encode notification type

Currently there are only two types of in-kernel nexthop notification.
The two are distinguished by the 'is_grp' boolean field in 'struct
nh_notifier_info'.

As more notification types are introduced for more next-hop group types, a
boolean is not an easily extensible interface. Instead, convert it to an
enum.
Signed-off-by: Ido Schimmel <idosch@nvidia.com>
Reviewed-by: Petr Machata <petrm@nvidia.com>
Signed-off-by: Petr Machata <petrm@nvidia.com>
Reviewed-by: David Ahern <dsahern@kernel.org>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

drivers/net/ethernet/mellanox/mlxsw/spectrum_router.c

@@ -4309,11 +4309,18 @@ static int mlxsw_sp_nexthop_obj_validate(struct mlxsw_sp *mlxsw_sp,
 	if (event != NEXTHOP_EVENT_REPLACE)
 		return 0;
 
-	if (!info->is_grp)
+	switch (info->type) {
+	case NH_NOTIFIER_INFO_TYPE_SINGLE:
 		return mlxsw_sp_nexthop_obj_single_validate(mlxsw_sp, info->nh,
 							    info->extack);
-	return mlxsw_sp_nexthop_obj_group_validate(mlxsw_sp, info->nh_grp,
-						   info->extack);
+	case NH_NOTIFIER_INFO_TYPE_GRP:
+		return mlxsw_sp_nexthop_obj_group_validate(mlxsw_sp,
+							   info->nh_grp,
+							   info->extack);
+	default:
+		NL_SET_ERR_MSG_MOD(info->extack, "Unsupported nexthop type");
+		return -EOPNOTSUPP;
+	}
 }
 
 static bool mlxsw_sp_nexthop_obj_is_gateway(struct mlxsw_sp *mlxsw_sp,
@@ -4321,13 +4328,17 @@ static bool mlxsw_sp_nexthop_obj_is_gateway(struct mlxsw_sp *mlxsw_sp,
 {
 	const struct net_device *dev;
 
-	if (info->is_grp)
+	switch (info->type) {
+	case NH_NOTIFIER_INFO_TYPE_SINGLE:
+		dev = info->nh->dev;
+		return info->nh->gw_family || info->nh->is_reject ||
+		       mlxsw_sp_netdev_ipip_type(mlxsw_sp, dev, NULL);
+	case NH_NOTIFIER_INFO_TYPE_GRP:
 		/* Already validated earlier. */
 		return true;
-
-	dev = info->nh->dev;
-	return info->nh->gw_family || info->nh->is_reject ||
-	       mlxsw_sp_netdev_ipip_type(mlxsw_sp, dev, NULL);
+	default:
+		return false;
+	}
 }
 
 static void mlxsw_sp_nexthop_obj_blackhole_init(struct mlxsw_sp *mlxsw_sp,
@@ -4410,11 +4421,22 @@ mlxsw_sp_nexthop_obj_group_info_init(struct mlxsw_sp *mlxsw_sp,
 				     struct mlxsw_sp_nexthop_group *nh_grp,
 				     struct nh_notifier_info *info)
 {
-	unsigned int nhs = info->is_grp ? info->nh_grp->num_nh : 1;
 	struct mlxsw_sp_nexthop_group_info *nhgi;
 	struct mlxsw_sp_nexthop *nh;
+	unsigned int nhs;
 	int err, i;
 
+	switch (info->type) {
+	case NH_NOTIFIER_INFO_TYPE_SINGLE:
+		nhs = 1;
+		break;
+	case NH_NOTIFIER_INFO_TYPE_GRP:
+		nhs = info->nh_grp->num_nh;
+		break;
+	default:
+		return -EINVAL;
+	}
+
 	nhgi = kzalloc(struct_size(nhgi, nexthops, nhs), GFP_KERNEL);
 	if (!nhgi)
 		return -ENOMEM;
@@ -4427,12 +4449,18 @@ mlxsw_sp_nexthop_obj_group_info_init(struct mlxsw_sp *mlxsw_sp,
 		int weight;
 
 		nh = &nhgi->nexthops[i];
-		if (info->is_grp) {
-			nh_obj = &info->nh_grp->nh_entries[i].nh;
-			weight = info->nh_grp->nh_entries[i].weight;
-		} else {
+		switch (info->type) {
+		case NH_NOTIFIER_INFO_TYPE_SINGLE:
 			nh_obj = info->nh;
 			weight = 1;
+			break;
+		case NH_NOTIFIER_INFO_TYPE_GRP:
+			nh_obj = &info->nh_grp->nh_entries[i].nh;
+			weight = info->nh_grp->nh_entries[i].weight;
+			break;
+		default:
+			err = -EINVAL;
+			goto err_nexthop_obj_init;
 		}
 		err = mlxsw_sp_nexthop_obj_init(mlxsw_sp, nh_grp, nh, nh_obj,
 						weight);

drivers/net/netdevsim/fib.c

@@ -860,7 +860,7 @@ static struct nsim_nexthop *nsim_nexthop_create(struct nsim_fib_data *data,
 
 	nexthop = kzalloc(sizeof(*nexthop), GFP_KERNEL);
 	if (!nexthop)
-		return NULL;
+		return ERR_PTR(-ENOMEM);
 
 	nexthop->id = info->id;
 
@@ -868,15 +868,20 @@ static struct nsim_nexthop *nsim_nexthop_create(struct nsim_fib_data *data,
 	 * occupy.
 	 */
 
-	if (!info->is_grp) {
+	switch (info->type) {
+	case NH_NOTIFIER_INFO_TYPE_SINGLE:
 		occ = 1;
-		goto out;
+		break;
+	case NH_NOTIFIER_INFO_TYPE_GRP:
+		for (i = 0; i < info->nh_grp->num_nh; i++)
+			occ += info->nh_grp->nh_entries[i].weight;
+		break;
+	default:
+		NL_SET_ERR_MSG_MOD(info->extack, "Unsupported nexthop type");
+		kfree(nexthop);
+		return ERR_PTR(-EOPNOTSUPP);
 	}
 
-	for (i = 0; i < info->nh_grp->num_nh; i++)
-		occ += info->nh_grp->nh_entries[i].weight;
-
-out:
 	nexthop->occ = occ;
 	return nexthop;
 }
@@ -972,8 +977,8 @@ static int nsim_nexthop_insert(struct nsim_fib_data *data,
 	int err;
 
 	nexthop = nsim_nexthop_create(data, info);
-	if (!nexthop)
-		return -ENOMEM;
+	if (IS_ERR(nexthop))
+		return PTR_ERR(nexthop);
 
 	nexthop_old = rhashtable_lookup_fast(&data->nexthop_ht, &info->id,
 					     nsim_nexthop_ht_params);

include/net/nexthop.h

@@ -114,6 +114,11 @@ enum nexthop_event_type {
 	NEXTHOP_EVENT_REPLACE,
 };
 
+enum nh_notifier_info_type {
+	NH_NOTIFIER_INFO_TYPE_SINGLE,
+	NH_NOTIFIER_INFO_TYPE_GRP,
+};
+
 struct nh_notifier_single_info {
 	struct net_device *dev;
 	u8 gw_family;
@@ -142,7 +147,7 @@ struct nh_notifier_info {
 	struct net *net;
 	struct netlink_ext_ack *extack;
 	u32 id;
-	bool is_grp;
+	enum nh_notifier_info_type type;
 	union {
 		struct nh_notifier_single_info *nh;
 		struct nh_notifier_grp_info *nh_grp;

net/ipv4/nexthop.c

@@ -71,6 +71,7 @@ __nh_notifier_single_info_init(struct nh_notifier_single_info *nh_info,
 static int nh_notifier_single_info_init(struct nh_notifier_info *info,
 					const struct nexthop *nh)
 {
+	info->type = NH_NOTIFIER_INFO_TYPE_SINGLE;
 	info->nh = kzalloc(sizeof(*info->nh), GFP_KERNEL);
 	if (!info->nh)
 		return -ENOMEM;
@@ -92,6 +93,7 @@ static int nh_notifier_grp_info_init(struct nh_notifier_info *info,
 	u16 num_nh = nhg->num_nh;
 	int i;
 
+	info->type = NH_NOTIFIER_INFO_TYPE_GRP;
 	info->nh_grp = kzalloc(struct_size(info->nh_grp, nh_entries, num_nh),
 			       GFP_KERNEL);
 	if (!info->nh_grp)
@@ -121,17 +123,17 @@ static int nh_notifier_info_init(struct nh_notifier_info *info,
 				 const struct nexthop *nh)
 {
 	info->id = nh->id;
-	info->is_grp = nh->is_group;
 
-	if (info->is_grp)
+	if (nh->is_group)
 		return nh_notifier_grp_info_init(info, nh);
 	else
 		return nh_notifier_single_info_init(info, nh);
 }
 
-static void nh_notifier_info_fini(struct nh_notifier_info *info)
+static void nh_notifier_info_fini(struct nh_notifier_info *info,
+				  const struct nexthop *nh)
 {
-	if (info->is_grp)
+	if (nh->is_group)
 		nh_notifier_grp_info_fini(info);
 	else
 		nh_notifier_single_info_fini(info);
@@ -161,7 +163,7 @@ static int call_nexthop_notifiers(struct net *net,
 
 	err = blocking_notifier_call_chain(&net->nexthop.notifier_chain,
 					   event_type, &info);
-	nh_notifier_info_fini(&info);
+	nh_notifier_info_fini(&info, nh);
 
 	return notifier_to_errno(err);
 }
@@ -182,7 +184,7 @@ static int call_nexthop_notifier(struct notifier_block *nb, struct net *net,
 		return err;
 
 	err = nb->notifier_call(nb, event_type, &info);
-	nh_notifier_info_fini(&info);
+	nh_notifier_info_fini(&info, nh);
 
 	return notifier_to_errno(err);
 }