mm: use non-racy method for /proc/swaps creation

Use proc_create() to make sure that ->proc_fops be setup before gluing PDE to
main tree.

Signed-off-by: Denis V. Lunev <den@openvz.org>
Cc: Alexey Dobriyan <adobriyan@gmail.com>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

mm/swapfile.c

@@ -1426,11 +1426,7 @@ static const struct file_operations proc_swaps_operations = {
 
 static int __init procswaps_init(void)
 {
-	struct proc_dir_entry *entry;
-
-	entry = create_proc_entry("swaps", 0, NULL);
-	if (entry)
-		entry->proc_fops = &proc_swaps_operations;
+	proc_create("swaps", 0, NULL, &proc_swaps_operations);
 	return 0;
 }
 __initcall(procswaps_init);