net/mlx5e: Block entering switchdev mode with ns inconsistency

[ Upstream commit 662404b24a4c4d839839ed25e3097571f5938b9b ]

Upon entering switchdev mode, VF/SF representors are spawned in the
devlink instance's net namespace, whereas the PF net device transforms
into the uplink representor, remaining in the net namespace the PF net
device was in. Therefore, if a PF net device's namespace is different from
its parent devlink net namespace, entering switchdev mode can create an
illegal situation where all representors sharing the same core device
are NOT in the same net namespace.

To avoid this issue, block entering switchdev mode for devices whose child
netdev net namespace has diverged from the parent devlink's.

Fixes: 7768d1971de6 ("net/mlx5: E-Switch, Add control for encapsulation")
Signed-off-by: Gavin Li <gavinl@nvidia.com>
Reviewed-by: Gavi Teitz <gavi@nvidia.com>
Signed-off-by: Saeed Mahameed <saeedm@nvidia.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>

diff --git a/drivers/net/ethernet/mellanox/mlx5/core/eswitch_offloads.c b/drivers/net/ethernet/mellanox/mlx5/core/eswitch_offloads.c
index 34790a82a09767a66506309b750b9065e63541b7..64e5b9f29206e156bb27fe66dd20b879fb746af0 100644 (file)
--- a/drivers/net/ethernet/mellanox/mlx5/core/eswitch_offloads.c
+++ b/drivers/net/ethernet/mellanox/mlx5/core/eswitch_offloads.c
@@ -3488,6 +3488,18 @@ static int esw_inline_mode_to_devlink(u8 mlx5_mode, u8 *mode)
        return 0;
 }
 
+static bool esw_offloads_devlink_ns_eq_netdev_ns(struct devlink *devlink)
+{
+       struct net *devl_net, *netdev_net;
+       struct mlx5_eswitch *esw;
+
+       esw = mlx5_devlink_eswitch_get(devlink);
+       netdev_net = dev_net(esw->dev->mlx5e_res.uplink_netdev);
+       devl_net = devlink_net(devlink);
+
+       return net_eq(devl_net, netdev_net);
+}
+
 int mlx5_devlink_eswitch_mode_set(struct devlink *devlink, u16 mode,
                                  struct netlink_ext_ack *extack)
 {
@@ -3502,6 +3514,13 @@ int mlx5_devlink_eswitch_mode_set(struct devlink *devlink, u16 mode,
        if (esw_mode_from_devlink(mode, &mlx5_mode))
                return -EINVAL;
 
+       if (mode == DEVLINK_ESWITCH_MODE_SWITCHDEV &&
+           !esw_offloads_devlink_ns_eq_netdev_ns(devlink)) {
+               NL_SET_ERR_MSG_MOD(extack,
+                                  "Can't change E-Switch mode to switchdev when netdev net namespace has diverged from the devlink's.");
+               return -EPERM;
+       }
+
        mlx5_lag_disable_change(esw->dev);
        err = mlx5_esw_try_lock(esw);
        if (err < 0) {