Commit fca1cdd3 authored Feb 03, 2020 by Huy Nguyen Committed by Greg Kroah-Hartman Feb 28, 2020

net/mlx5: Fix sleep while atomic in mlx5_eswitch_get_vepa



commit 3d9c5e023a0dbf3e117bb416cfefd9405bf5af0c upstream.

rtnl_bridge_getlink is protected by rcu lock, so mlx5_eswitch_get_vepa
cannot take mutex lock. Two possible issues can happen:
1. User at the same time change vepa mode via RTM_SETLINK command.
2. User at the same time change the switchdev mode via devlink netlink
interface.

Case 1 cannot happen because rtnl executes one message in order.
Case 2 can happen but we do not expect user to change the switchdev mode
when changing vepa. Even if a user does it, so he will read a value
which is no longer valid.

Fixes: 8da202b2 ("net/mlx5: E-Switch, Add support for VEPA in legacy mode.")
Signed-off-by: Huy Nguyen <huyn@mellanox.com>
Reviewed-by: Mark Bloch <markb@mellanox.com>
Signed-off-by: Saeed Mahameed <saeedm@mellanox.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

parent 06320052

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

+3 −11

Original line number	Diff line number	Diff line
		@@ -2319,25 +2319,17 @@ int mlx5_eswitch_set_vepa(struct mlx5_eswitch *esw, u8 setting)

		int mlx5_eswitch_get_vepa(struct mlx5_eswitch esw, u8 setting)
		{
		int err = 0;

		if (!esw)
		return -EOPNOTSUPP;

		if (!ESW_ALLOWED(esw))
		return -EPERM;

		mutex_lock(&esw->state_lock);
		if (esw->mode != MLX5_ESWITCH_LEGACY) {
		err = -EOPNOTSUPP;
		goto out;
		}
		if (esw->mode != MLX5_ESWITCH_LEGACY)
		return -EOPNOTSUPP;

		*setting = esw->fdb_table.legacy.vepa_uplink_rule ? 1 : 0;

		out:
		mutex_unlock(&esw->state_lock);
		return err;
		return 0;
		}

		int mlx5_eswitch_set_vport_trust(struct mlx5_eswitch *esw,