cgroup: switch to proc_create()

There is a race between create_proc_entry() and the assignment of file ops.
proc_create() is invented to fix it.

Signed-off-by: Li Zefan <[e-mail]>
Acked-by: Paul Menage <[e-mail]>
Signed-off-by: Andrew Morton <[e-mail]>
Signed-off-by: Linus Torvalds <[e-mail]>

kernel/cgroup.c

···
 {
 	int err;
 	int i;
-	struct proc_dir_entry *entry;
 
 	err = bdi_init(&cgroup_backing_dev_info);
 	if (err)
···
 	if (err < 0)
 		goto out;
 
-	entry = create_proc_entry("cgroups", 0, NULL);
-	if (entry)
-		entry->proc_fops = &proc_cgroupstats_operations;
+	proc_create("cgroups", 0, NULL, &proc_cgroupstats_operations);
 
 out:
 	if (err)