l2tp: close sessions before initiating tunnel delete
l2tp: close sessions before initiating tunnel delete

When a user deletes a tunnel using netlink, all the sessions in the tunnel
should also be deleted.  Since running sessions will pin the tunnel socket
with the references they hold, have the l2tp_tunnel_delete close all sessions
in a tunnel before finally closing the tunnel socket.

Signed-off-by: Tom Parkin <ea112d67cab4b46373b4d6536b035de78635308d@katalix.com>
Signed-off-by: James Chapman <d87d459960487ecb1b999dfc309f5d5f521df082@katalix.com>
Signed-off-by: David S. Miller <fe08d3c717adf2ae63592e4c9aec6e3e404d8e3e@davemloft.net>

KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,TeamVee-Kanas/android_kernel_samsung_kanas,TeamVee-Kanas/android_kernel_samsung_kanas,KristFoundation/Programs,TeamVee-Kanas/android_kernel_samsung_kanas,KristFoundation/Programs,KristFoundation/Programs,TeamVee-Kanas/android_kernel_samsung_kanas,TeamVee-Kanas/android_kernel_samsung_kanas