net/mlx5e: Fix crash unsetting rx-vlan-filter in switchdev mode

Moving to switchdev mode with rx-vlan-filter on and then setting it off
causes the kernel to crash since fs->vlan is freed during nic profile
cleanup flow.

RX VLAN filtering is not supported in switchdev mode so unset it when
changing to switchdev and restore its value when switching back to
legacy.

trace:
[] RIP: 0010:mlx5e_disable_cvlan_filter+0x43/0x70
[] set_feature_cvlan_filter+0x37/0x40 [mlx5_core]
[] mlx5e_handle_feature+0x3a/0x60 [mlx5_core]
[] mlx5e_set_features+0x6d/0x160 [mlx5_core]
[] __netdev_update_features+0x288/0xa70
[] ethnl_set_features+0x309/0x380
[] ? __nla_parse+0x21/0x30
[] genl_family_rcv_msg_doit.isra.17+0x110/0x150
[] genl_rcv_msg+0x112/0x260
[] ? features_reply_size+0xe0/0xe0
[] ? genl_family_rcv_msg_doit.isra.17+0x150/0x150
[] netlink_rcv_skb+0x4e/0x100
[] genl_rcv+0x24/0x40
[] netlink_unicast+0x1ab/0x290
[] netlink_sendmsg+0x257/0x4f0
[] sock_sendmsg+0x5c/0x70

Fixes: cb67b832 ("net/mlx5e: Introduce SRIOV VF representors")
Signed-off-by: Amir Tzin <amirtz@nvidia.com>
Reviewed-by: Maor Dickman <maord@nvidia.com>
Signed-off-by: Saeed Mahameed <saeedm@nvidia.com>

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

@@ -443,7 +443,7 @@ void mlx5e_enable_cvlan_filter(struct mlx5e_flow_steering *fs, bool promisc)
 
 void mlx5e_disable_cvlan_filter(struct mlx5e_flow_steering *fs, bool promisc)
 {
-	if (fs->vlan->cvlan_filter_disabled)
+	if (!fs->vlan || fs->vlan->cvlan_filter_disabled)
 		return;
 
 	fs->vlan->cvlan_filter_disabled = true;

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

@@ -4018,6 +4018,10 @@ static netdev_features_t mlx5e_fix_uplink_rep_features(struct net_device *netdev
 	if (netdev->features & NETIF_F_GRO_HW)
 		netdev_warn(netdev, "Disabling HW_GRO, not supported in switchdev mode\n");
 
+	features &= ~NETIF_F_HW_VLAN_CTAG_FILTER;
+	if (netdev->features & NETIF_F_HW_VLAN_CTAG_FILTER)
+		netdev_warn(netdev, "Disabling HW_VLAN CTAG FILTERING, not supported in switchdev mode\n");
+
 	return features;
 }