Re: [B.A.T.M.A.N.] [PATCH v5 2/4] batman-adv: Modify mesh_iface outside sysfs context

[Marek Lindner <mareklindner@neomailbox.ch>]

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On Monday, June 13, 2016 07:41:30 Sven Eckelmann wrote:
> The legacy sysfs interface to modify interfaces belonging to batman-adv
> is run inside a region holding s_lock. And to add a net_device, it has
> to also get the rtnl_lock. This is exactly the other way around than in
> other virtual net_devices and conflicts with netdevice notifier which
> executes inside rtnl_lock.
> 
> The inverted lock situation is currently solved by executing the removal
> of netdevices via workqueue. The workqueue isn't executed inside
> rtnl_lock and thus can independently get the s_lock and the rtnl_lock.
> 
> But this workaround fails when the netdevice notifier creates events in
> quick succession and the earlier triggered removal of a net_device isn't
> processed in the workqueue before the adding of the new netdevice (with
> same name) event is issued.
> 
> Instead the legacy sysfs interface store events have to be enqueued in
> a workqueue to loose the s_lock. The worker is then free to get the
> required locks and the deadlock is avoided.
> 
> Signed-off-by: Sven Eckelmann <sven@narfation.org>
> ---
> v5:
>  - rebase on top of current master
> v4:
>  - rebase on top of current master
> v3:
>  - rebased on top of current master to fix conflicts with newest patches
> v2:
>  - rebased on top of current master to fix conflicts with newest patches
> ---
>  net/batman-adv/sysfs.c | 107
> +++++++++++++++++++++++++++++++++++++------------ net/batman-adv/types.h
> |  13 ++++++
>  2 files changed, 94 insertions(+), 26 deletions(-)

Applied in revision a1f0a80.

Thanks,
Marek

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