net: replace percpu_xxx funcs with this_cpu_xxx or __this_cpu_xxx

percpu_xxx funcs are duplicated with this_cpu_xxx funcs, so replace
them for further code clean up.

And in preempt safe scenario, __this_cpu_xxx funcs may has a bit
better performance since __this_cpu_xxx has no redundant
preempt_enable/preempt_disable on some architectures.

Signed-off-by: Alex Shi <alex.shi@intel.com>
Acked-by: Eric Dumazet <eric.dumazet@gmail.com>
Acked-by: David S. Miller <davem@davemloft.net>
Cc: Patrick McHardy <kaber@trash.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Tejun Heo <tj@kernel.org>
diff --git a/net/socket.c b/net/socket.c
index 851edcd..08e873a 100644
--- a/net/socket.c
+++ b/net/socket.c
@@ -479,7 +479,7 @@
 	inode->i_uid = current_fsuid();
 	inode->i_gid = current_fsgid();
 
-	percpu_add(sockets_in_use, 1);
+	this_cpu_add(sockets_in_use, 1);
 	return sock;
 }
 
@@ -522,7 +522,7 @@
 	if (rcu_dereference_protected(sock->wq, 1)->fasync_list)
 		printk(KERN_ERR "sock_release: fasync list not empty!\n");
 
-	percpu_sub(sockets_in_use, 1);
+	this_cpu_sub(sockets_in_use, 1);
 	if (!sock->file) {
 		iput(SOCK_INODE(sock));
 		return;