rtnetlink: remove redundant checks for nlattr IFLA_BRIDGE_MODE

The commit d73ef2d6 ("rtnetlink: let rtnl_bridge_setlink checks
IFLA_BRIDGE_MODE length") added the nla_len check in rtnl_bridge_setlink,
which is the only caller for ndo_bridge_setlink handlers defined in
low-level driver codes. Hence, this patch cleanups the redundant checks in
each ndo_bridge_setlink handler function.
Suggested-by: Hangbin Liu <liuhangbin@gmail.com>
Signed-off-by: Lin Ma <linma@zju.edu.cn>
Acked-by: Pavan Chebbi <pavan.chebbi@broadcom.com>
Reviewed-by: Simon Horman <horms@kernel.org>
Link: https://lore.kernel.org/r/20230807091347.3804523-1-linma@zju.edu.cnSigned-off-by: Jakub Kicinski <kuba@kernel.org>

drivers/net/ethernet/broadcom/bnxt/bnxt.c

@@ -13132,9 +13132,6 @@ static int bnxt_bridge_setlink(struct net_device *dev, struct nlmsghdr *nlh,
 		if (nla_type(attr) != IFLA_BRIDGE_MODE)
 			continue;
 
-		if (nla_len(attr) < sizeof(mode))
-			return -EINVAL;
-
 		mode = nla_get_u16(attr);
 		if (mode == bp->br_mode)
 			break;

drivers/net/ethernet/emulex/benet/be_main.c

@@ -4986,9 +4986,6 @@ static int be_ndo_bridge_setlink(struct net_device *dev, struct nlmsghdr *nlh,
 		if (nla_type(attr) != IFLA_BRIDGE_MODE)
 			continue;
 
-		if (nla_len(attr) < sizeof(mode))
-			return -EINVAL;
-
 		mode = nla_get_u16(attr);
 		if (BE3_chip(adapter) && mode == BRIDGE_MODE_VEPA)
 			return -EOPNOTSUPP;

drivers/net/ethernet/intel/ixgbe/ixgbe_main.c

@@ -10042,9 +10042,6 @@ static int ixgbe_ndo_bridge_setlink(struct net_device *dev,
 		if (nla_type(attr) != IFLA_BRIDGE_MODE)
 			continue;
 
-		if (nla_len(attr) < sizeof(mode))
-			return -EINVAL;
-
 		mode = nla_get_u16(attr);
 		status = ixgbe_configure_bridge_mode(adapter, mode);
 		if (status)

drivers/net/ethernet/mellanox/mlx5/core/en_main.c

@@ -4896,9 +4896,6 @@ static int mlx5e_bridge_setlink(struct net_device *dev, struct nlmsghdr *nlh,
 		if (nla_type(attr) != IFLA_BRIDGE_MODE)
 			continue;
 
-		if (nla_len(attr) < sizeof(mode))
-			return -EINVAL;
-
 		mode = nla_get_u16(attr);
 		if (mode > BRIDGE_MODE_VEPA)
 			return -EINVAL;

drivers/net/ethernet/netronome/nfp/nfp_net_common.c

@@ -2108,9 +2108,6 @@ static int nfp_net_bridge_setlink(struct net_device *dev, struct nlmsghdr *nlh,
 		if (nla_type(attr) != IFLA_BRIDGE_MODE)
 			continue;
 
-		if (nla_len(attr) < sizeof(mode))
-			return -EINVAL;
-
 		new_ctrl = nn->dp.ctrl;
 		mode = nla_get_u16(attr);
 		if (mode == BRIDGE_MODE_VEPA)