Re: [PATCH 1/5] 8021q: Vlan driver should use rcu_barrier() on unload instead of syncronize_net()

Paul E. McKenney
2009-06-08T15:54:46Z

On Mon, Jun 08, 2009 at 03:11:28PM +0200, Jesper Dangaard Brouer wrote:
> The VLAN 8021q driver needs to call rcu_barrier() when unloading the module,
> instead of syncronize_net(). This is needed to make sure that outstanding
> call_rcu() callbacks have completed, before the callback function code is
> removed on module unload.

Looks good! And thank you for checking up on this!!!

Reviewed-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>

> Signed-off-by: Jesper Dangaard Brouer <hawk@comx.dk>
> ---
>
> net/8021q/vlan.c | 2 +-
> 1 files changed, 1 insertions(+), 1 deletions(-)
>
> diff --git a/net/8021q/vlan.c b/net/8021q/vlan.c
> index 714e1c3..fe64908 100644
> --- a/net/8021q/vlan.c
> +++ b/net/8021q/vlan.c
> @@ -758,7 +758,7 @@ static void __exit vlan_cleanup_module(void)
> BUG_ON(!hlist_empty(&vlan_group_hash[i]));
>
> unregister_pernet_gen_device(vlan_net_id, &vlan_net_ops);
> - synchronize_net();
> + rcu_barrier(); /* Wait for completion of call_rcu()'s */
>
> vlan_gvrp_uninit();
> }
>