Commit Graph

58 Commits

Author SHA1 Message Date
Pavel Emelyanov 1dba323b3f [NETNS]: Make the init/exit hooks checks outside the loop
When the new pernet something (subsys, device or operations) is
being registered, the init callback is to be called for each
namespace, that currently exitst in the system. During the
unregister, the same is to be done with the exit callback.

However, not every pernet something has both calls, but the
check for the appropriate pointer to be not NULL is performed
inside the for_each_net() loop.

This is (at least) strange, so tune this.

Signed-off-by: Pavel Emelyanov <xemul@openvz.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
2007-11-01 00:42:43 -07:00
Daniel Lezcano 310928d963 [NETNS]: fix net released by rcu callback
When a network namespace reference is held by a network subsystem,
and when this reference is decremented in a rcu update callback, we
must ensure that there is no more outstanding rcu update before
trying to free the network namespace.

In the normal case, the rcu_barrier is called when the network namespace
is exiting in the cleanup_net function.

But when a network namespace creation fails, and the subsystems are
undone (like the cleanup), the rcu_barrier is missing.

This patch adds the missing rcu_barrier.

Signed-off-by: Daniel Lezcano <dlezcano@fr.ibm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2007-10-30 21:16:21 -07:00
Pavel Emelyanov 32f0c4cbe4 [NETNS]: Don't memset() netns to zero manually
The newly created net namespace is set to 0 with memset()
in setup_net(). The setup_net() is also called for the
init_net_ns(), which is zeroed naturally as a global var.

So remove this memset and allocate new nets with the
kmem_cache_zalloc().

Signed-off-by: Pavel Emelyanov <xemul@openvz.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
2007-10-10 16:54:59 -07:00
Eric W. Biederman f4618d39a3 [NETNS]: Simplify the network namespace list locking rules.
Denis V. Lunev <den@sw.ru> noticed that the locking rules
for the network namespace list are over complicated and broken.

In particular the current register_netdev_notifier currently
does not take any lock making the for_each_net iteration racy
with network namespace creation and destruction. Oops.

The fact that we need to use for_each_net in rtnl_unlock() when
the rtnetlink support becomes per network namespace makes designing
the proper locking tricky.  In addition we need to be able to call
rtnl_lock() and rtnl_unlock() when we have the net_mutex held.

After thinking about it and looking at the alternatives carefully
it looks like the simplest and most maintainable solution is
to remove net_list_mutex altogether, and to use the rtnl_mutex instead.

Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2007-10-10 16:52:55 -07:00
Eric W. Biederman 9dd776b6d7 [NET]: Add network namespace clone & unshare support.
This patch allows you to create a new network namespace
using sys_clone, or sys_unshare.

As the network namespace is still experimental and under development
clone and unshare support is only made available when CONFIG_NET_NS is
selected at compile time.

As this patch introduces network namespace support into code paths
that exist when the CONFIG_NET is not selected there are a few
additions made to net_namespace.h to allow a few more functions
to be used when the networking stack is not compiled in.

Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2007-10-10 16:52:46 -07:00
Pavel Emelyanov 768f3591e2 [NETNS]: Cleanup list walking in setup_net and cleanup_net
I proposed introducing a list_for_each_entry_continue_reverse macro
to be used in setup_net() when unrolling the failed ->init callback.

Here is the macro and some more cleanup in the setup_net() itself
to remove one variable from the stack :) The same thing is for the
cleanup_net() - the existing list_for_each_entry_reverse() is used.

Minor, but the code looks nicer.

Signed-off-by: Pavel Emelyanov <xemul@openvz.org>
Acked-by: "Eric W. Biederman" <ebiederm@xmission.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2007-10-10 16:51:35 -07:00
David S. Miller 678aa8e4eb [NET]: #if 0 out net_alloc() for now.
We will undo this once it is actually used.

Signed-off-by: David S. Miller <davem@davemloft.net>
2007-10-10 16:49:14 -07:00
Eric W. Biederman 5f256becd8 [NET]: Basic network namespace infrastructure.
This is the basic infrastructure needed to support network
namespaces.  This infrastructure is:
- Registration functions to support initializing per network
  namespace data when a network namespaces is created or destroyed.

- struct net.  The network namespace data structure.
  This structure will grow as variables are made per network
  namespace but this is the minimal starting point.

- Functions to grab a reference to the network namespace.
  I provide both get/put functions that keep a network namespace
  from being freed.  And hold/release functions serve as weak references
  and will warn if their count is not zero when the data structure
  is freed.  Useful for dealing with more complicated data structures
  like the ipv4 route cache.

- A list of all of the network namespaces so we can iterate over them.

- A slab for the network namespace data structure allowing leaks
  to be spotted.

Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2007-10-10 16:49:03 -07:00