linux/include/net/netns
Pavel Emelyanov dec827d174 [NETNS]: The generic per-net pointers.
Add the elastic array of void * pointer to the struct net.
The access rules are simple:

 1. register the ops with register_pernet_gen_device to get
    the id of your private pointer
 2. call net_assign_generic() to put the private data on the
    struct net (most preferably this should be done in the
    ->init callback of the ops registered)
 3. do not store any private reference on the net_generic array;
 4. do not change this pointer while the net is alive;
 5. use the net_generic() to get the pointer.

When adding a new pointer, I copy the old array, replace it
with a new one and schedule the old for kfree after an RCU
grace period.

Since the net_generic explores the net->gen array inside rcu
read section and once set the net->gen->ptr[x] pointer never 
changes, this grants us a safe access to generic pointers.

Quoting Paul: "... RCU is protecting -only- the net_generic 
structure that net_generic() is traversing, and the [pointer]
returned by net_generic() is protected by a reference counter 
in the upper-level struct net."

Signed-off-by: Pavel Emelyanov <xemul@openvz.org>
Acked-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2008-04-15 00:36:08 -07:00
..
core.h [SOCK][NETNS]: Add the percpu prot_inuse counter in the struct net. 2008-03-31 19:42:16 -07:00
dccp.h [NETNS][DCCPV6]: Move the dccp_v6_ctl_sk on the struct net. 2008-04-13 22:32:25 -07:00
generic.h [NETNS]: The generic per-net pointers. 2008-04-15 00:36:08 -07:00
ipv4.h [NETNS]: Create tcp control socket in the each namespace. 2008-04-03 14:31:33 -07:00
ipv6.h [NETNS][IPV6] mcast - handle several network namespace 2008-03-07 11:16:55 -08:00
packet.h [NETNS]: separate af_packet netns data 2008-01-28 14:57:15 -08:00
unix.h
x_tables.h [NETFILTER]: x_tables: per-netns xt_tables 2008-01-31 19:27:35 -08:00