net: use this_cpu_ptr()

use this_cpu_ptr(p) instead of per_cpu_ptr(p, smp_processor_id())

Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/ipv4/tcp.c b/net/ipv4/tcp.c
index d5f84bd..4e6ddfb 100644
--- a/net/ipv4/tcp.c
+++ b/net/ipv4/tcp.c
@@ -2962,7 +2962,7 @@
 	spin_unlock(&tcp_md5sig_pool_lock);
 
 	if (p)
-		return *per_cpu_ptr(p, smp_processor_id());
+		return *this_cpu_ptr(p);
 
 	local_bh_enable();
 	return NULL;