ipv6: Use interface max_desync_factor instead of static default

max_desync_factor can be configured per-interface, but nothing is
using the value.

Reported-by: Piotr Lewandowski <piotr.lewandowski@gmail.com>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/ipv6/addrconf.c

@@ -121,8 +121,6 @@ static inline void addrconf_sysctl_unregister(struct inet6_dev *idev)
 static int __ipv6_regen_rndid(struct inet6_dev *idev);
 static int __ipv6_try_regen_rndid(struct inet6_dev *idev, struct in6_addr *tmpaddr);
 static void ipv6_regen_rndid(unsigned long data);
-
-static int desync_factor = MAX_DESYNC_FACTOR * HZ;
 #endif
 
 static int ipv6_generate_eui64(u8 *eui, struct net_device *dev);
@@ -893,7 +891,8 @@ static int ipv6_create_tempaddr(struct inet6_ifaddr *ifp, struct inet6_ifaddr *i
 			      idev->cnf.temp_valid_lft);
 	tmp_prefered_lft = min_t(__u32,
 				 ifp->prefered_lft,
-				 idev->cnf.temp_prefered_lft - desync_factor / HZ);
+				 idev->cnf.temp_prefered_lft -
+				 idev->cnf.max_desync_factor);
 	tmp_plen = ifp->prefix_len;
 	max_addresses = idev->cnf.max_addresses;
 	tmp_cstamp = ifp->cstamp;
@@ -1653,7 +1652,8 @@ static void ipv6_regen_rndid(unsigned long data)
 
 	expires = jiffies +
 		idev->cnf.temp_prefered_lft * HZ -
-		idev->cnf.regen_max_retry * idev->cnf.dad_transmits * idev->nd_parms->retrans_time - desync_factor;
+		idev->cnf.regen_max_retry * idev->cnf.dad_transmits * idev->nd_parms->retrans_time -
+		idev->cnf.max_desync_factor * HZ;
 	if (time_before(expires, jiffies)) {
 		printk(KERN_WARNING
 			"ipv6_regen_rndid(): too short regeneration interval; timer disabled for %s.\n",