Commit 10256deb authored Mar 29, 2018 by Kirill Tkhai Committed by David S. Miller Mar 29, 2018

net: Don't take rtnl_lock() in wireless_nlevent_flush()



This function iterates over net_namespace_list and flushes
the queue for every of them. What does this rtnl_lock()
protects?! Since we may add skbs to net::wext_nlevents
without rtnl_lock(), it does not protects us about queuers.

It guarantees, two threads can't flush the queue in parallel,
that can change the order, but since skb can be queued
in any order, it doesn't matter, how many threads do this
in parallel. In case of several threads, this will be even
faster.

So, we can remove rtnl_lock() here, as it was used for
iteration over net_namespace_list only.

Signed-off-by: Kirill Tkhai <ktkhai@virtuozzo.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

parent f0b07bb1

net/wireless/wext-core.c

+0 −4

Original line number	Diff line number	Diff line
		@@ -347,8 +347,6 @@ void wireless_nlevent_flush(void)
		struct sk_buff *skb;
		struct net *net;

		ASSERT_RTNL();

		down_read(&net_rwsem);
		for_each_net(net) {
		while ((skb = skb_dequeue(&net->wext_nlevents)))
		@@ -412,9 +410,7 @@ subsys_initcall(wireless_nlevent_init);
		/* Process events generated by the wireless layer or the driver. */
		static void wireless_nlevent_process(struct work_struct *work)
		{
		rtnl_lock();
		wireless_nlevent_flush();
		rtnl_unlock();
		}

		static DECLARE_WORK(wireless_nlevent_work, wireless_nlevent_process);

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