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Commit 81c684d1 authored by Denis V. Lunev's avatar Denis V. Lunev Committed by David S. Miller
Browse files

ipv4: remove flush_mutex from ipv4_sysctl_rtcache_flush 



It is possible to avoid locking at all in ipv4_sysctl_rtcache_flush by
defining local ctl_table on the stack.

The patch is based on the suggestion from Eric W. Biederman.

Signed-off-by: default avatarDenis V. Lunev <den@openvz.org>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 2c693610

net/ipv4/route.c

+6 −8
Original line number Diff line number Diff line
@@ -2873,22 +2873,20 @@ void ip_rt_multicast_event(struct in_device *in_dev) 
}



#ifdef CONFIG_SYSCTL

static int ipv4_sysctl_rtcache_flush(ctl_table *ctl, int write,

static int ipv4_sysctl_rtcache_flush(ctl_table *__ctl, int write,

					struct file *filp, void __user *buffer,

					size_t *lenp, loff_t *ppos)

{

	if (write) {

		int flush_delay;

		ctl_table ctl;

		struct net *net;

		static DEFINE_MUTEX(flush_mutex);



		mutex_lock(&flush_mutex);

		ctl->data = &flush_delay;

		proc_dointvec(ctl, write, filp, buffer, lenp, ppos);

		ctl->data = NULL;

		mutex_unlock(&flush_mutex);

		memcpy(&ctl, __ctl, sizeof(ctl));

		ctl.data = &flush_delay;

		proc_dointvec(&ctl, write, filp, buffer, lenp, ppos);



		net = (struct net *)ctl->extra1;

		net = (struct net *)__ctl->extra1;

		rt_cache_flush(net, flush_delay);

		return 0;

	}