Commit 1536cc0d authored Oct 10, 2007 by Denis V. Lunev Committed by David S. Miller Oct 10, 2007

[NET]: rtnl_unlock cleanups



There is no need to process outstanding netlink user->kernel packets
during rtnl_unlock now. There is no rtnl_trylock in the rtnetlink_rcv
anymore.

Normal code path is the following:
netlink_sendmsg
   netlink_unicast
       netlink_sendskb
           skb_queue_tail
           netlink_data_ready
               rtnetlink_rcv
                   mutex_lock(&rtnl_mutex);
                   netlink_run_queue(sk, qlen, &rtnetlink_rcv_msg);
                   mutex_unlock(&rtnl_mutex);

So, it is possible, that packets can be present in the rtnl->sk_receive_queue
during rtnl_unlock, but there is no need to process them at that moment as
rtnetlink_rcv for that packet is pending.

Signed-off-by: Denis V. Lunev <den@openvz.org>
Acked-by: Alexey Kuznetsov <kuznet@ms2.inr.ac.ru>
Signed-off-by: David S. Miller <davem@davemloft.net>

parent d1ec3b77

net/core/rtnetlink.c

+2 −6

Original line number	Diff line number	Diff line
		@@ -75,8 +75,6 @@ void __rtnl_unlock(void)
		void rtnl_unlock(void)
		{
		mutex_unlock(&rtnl_mutex);
		if (rtnl && rtnl->sk_receive_queue.qlen)
		rtnl->sk_data_ready(rtnl, 0);
		netdev_run_todo();
		}

		@@ -1319,11 +1317,9 @@ static void rtnetlink_rcv(struct sock *sk, int len)
		unsigned int qlen = 0;

		do {
		mutex_lock(&rtnl_mutex);
		rtnl_lock();
		qlen = netlink_run_queue(sk, qlen, &rtnetlink_rcv_msg);
		mutex_unlock(&rtnl_mutex);

		netdev_run_todo();
		rtnl_unlock();
		} while (qlen);
		}