Re: [B.A.T.M.A.N.] [PATCH 1/2] batman-adv: Fix reference counting of vlan object for tt_local_entry

[Antonio Quartulli <a@unstable.cc>]

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On Fri, Mar 11, 2016 at 04:44:05PM +0100, Sven Eckelmann wrote:
> The batadv_tt_local_entry was specific to a batadv_softif_vlan and held an
> implicit reference to it. But this reference was never stored in form of a
> pointer in the tt_local_entry itself. Instead batadv_tt_local_remove,
> batadv_tt_local_table_free and batadv_tt_local_purge_pending_clients depend
> on a consistent state of bat_priv->softif_vlan_list and that
> batadv_softif_vlan_get always returns the batadv_softif_vlan object which
> it has a reference for. But batadv_softif_vlan_get cannot guarantee that
> because it is working only with rcu_read_lock on this list. It can
> therefore happen that an vid is in this list twice or that
> batadv_softif_vlan_get cannot find the batadv_softif_vlan for an vid due to
> some other list operations taking place at the same time.
> 
> Instead add a batadv_softif_vlan pointer directly in batadv_tt_local_entry
> which will be used for the reference counter decremented on release of
> batadv_tt_local_entry.
> 
> Fixes: 9729d2085c0f ("batman-adv: fix TT VLAN inconsistency on VLAN re-add")
> Signed-off-by: Sven Eckelmann <sven@narfation.org>

Thanks a lot Sven ! This change, on top of fixing the ref issue, also simplified
the code quite a lot!

Acked-by: Antonio Quartulli <a@unstable.cc>

-- 
Antonio Quartulli

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