ipv6: use this_cpu_read() in rt6_get_pcpu_route()

this_cpu_read(*X) is faster than *this_cpu_ptr(X)
Signed-off-by: NEric Dumazet <edumazet@google.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

net/ipv6/route.c

@@ -1268,10 +1268,9 @@ static struct rt6_info *ip6_rt_pcpu_alloc(const struct fib6_result *res)
 /* It should be called with rcu_read_lock() acquired */
 static struct rt6_info *rt6_get_pcpu_route(const struct fib6_result *res)
 {
-	struct rt6_info *pcpu_rt, **p;
+	struct rt6_info *pcpu_rt;
 
-	p = this_cpu_ptr(res->nh->rt6i_pcpu);
-	pcpu_rt = *p;
+	pcpu_rt = this_cpu_read(*res->nh->rt6i_pcpu);
 
 	if (pcpu_rt)
 		ip6_hold_safe(NULL, &pcpu_rt);