pfcp: Support per-netns netdev unregistration.

pfcp_net_exit_rtnl() iterates pfcp devices whose sockets
are in the dying netns and queues them for destruction.

So the devices may reside in different netns.

Let's use unregister_netdevice_queue_net() to support per-netns
device unregistration.

list_del() is changed to list_del_init() to avoid queueing the
same device twice.

Even after pfcp_net_exit_rtnl() queues a cross-netns pfcp device,
pfcp_dellink() could be called concurrently for it (once RTNL is
removed).  In such a case, __rtnl_net_unlock() will perform the
unregistration.

We can see pfcp0 below is unregistered by the per-netns work
instead of cleanup_net().

  # bpftrace -e '#include <linux/netdevice.h>
  kprobe:pfcp_dev_uninit {
      $dev = (struct net_device *)arg0;
      printf("PID: %d | DEV: %s%s\n", pid, $dev->name, kstack());
  }
  kprobe:pfcp_net_exit_rtnl {
      printf("PID: %d%s\n", pid, kstack());
  }' &

  # ip netns add ns1
  # ip netns add ns2
  # ip -n ns1 link add pfcp0 link-netns ns2 type pfcp
  # ip netns del ns2

  PID: 12
          pfcp_net_exit_rtnl+5
          ops_undo_list+702
          cleanup_net+1122
          process_scheduled_works+2538
  ...
  PID: 462 | DEV: pfcp0
          pfcp_dev_uninit+5
          unregister_netdevice_many_notify+7129
          unregister_netdevice_many_net+1050
          rtnl_net_work_func+136
          process_scheduled_works+2538

Signed-off-by: Kuniyuki Iwashima <kuniyu@google.com>
Reviewed-by: Simon Horman <horms@kernel.org>
Link: https://patch.msgid.link/20260731224406.2444121-3-kuniyu@google.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

0 files changed, 0 insertions, 0 deletions