cgroup: make CFTYPE_ONLY_ON_DFL and CFTYPE_NO_ internal to cgroup core

cgroup now distinguishes cftypes for the default and legacy
hierarchies more explicitly by using separate arrays and
CFTYPE_ONLY_ON_DFL and CFTYPE_INSANE should be and are used only
inside cgroup core proper.  Let's make it clear that the flags are
internal by prefixing them with double underscores.

CFTYPE_INSANE is renamed to __CFTYPE_NOT_ON_DFL for consistency.  The
two flags are also collected and assigned bits >= 16 so that they
aren't mixed with the published flags.

v2: Convert the extra ones in cgroup_exit_cftypes() which are added by
    revision to the previous patch.

Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Li Zefan <lizefan@huawei.com>

include/linux/cgroup.h

diff --git a/include/linux/cgroup.h b/include/linux/cgroup.h
index 9f76236..b5223c5 100644
--- a/include/linux/cgroup.h
+++ b/include/linux/cgroup.h
@@ -384,9 +384,11 @@
 enum {
 	CFTYPE_ONLY_ON_ROOT	= (1 << 0),	/* only create on root cgrp */
 	CFTYPE_NOT_ON_ROOT	= (1 << 1),	/* don't create on root cgrp */
-	CFTYPE_INSANE		= (1 << 2),	/* don't create if sane_behavior */
 	CFTYPE_NO_PREFIX	= (1 << 3),	/* (DON'T USE FOR NEW FILES) no subsys prefix */
-	CFTYPE_ONLY_ON_DFL	= (1 << 4),	/* only on default hierarchy */
+
+	/* internal flags, do not use outside cgroup core proper */
+	__CFTYPE_ONLY_ON_DFL	= (1 << 16),	/* only on default hierarchy */
+	__CFTYPE_NOT_ON_DFL	= (1 << 17),	/* not on default hierarchy */
 };
 
 #define MAX_CFTYPE_NAME		64

kernel/cgroup.c

diff --git a/kernel/cgroup.c b/kernel/cgroup.c
index 374ebdf..f41d164 100644
--- a/kernel/cgroup.c
+++ b/kernel/cgroup.c
@@ -3031,9 +3031,9 @@
 
 	for (cft = cfts; cft->name[0] != '\0'; cft++) {
 		/* does cft->flags tell us to skip this file on @cgrp? */
-		if ((cft->flags & CFTYPE_ONLY_ON_DFL) && !cgroup_on_dfl(cgrp))
+		if ((cft->flags & __CFTYPE_ONLY_ON_DFL) && !cgroup_on_dfl(cgrp))
 			continue;
-		if ((cft->flags & CFTYPE_INSANE) && cgroup_on_dfl(cgrp))
+		if ((cft->flags & __CFTYPE_NOT_ON_DFL) && cgroup_on_dfl(cgrp))
 			continue;
 		if ((cft->flags & CFTYPE_NOT_ON_ROOT) && !cgroup_parent(cgrp))
 			continue;
@@ -3093,7 +3093,7 @@
 		cft->ss = NULL;
 
 		/* revert flags set by cgroup core while adding @cfts */
-		cft->flags &= ~(CFTYPE_ONLY_ON_DFL | CFTYPE_INSANE);
+		cft->flags &= ~(__CFTYPE_ONLY_ON_DFL | __CFTYPE_NOT_ON_DFL);
 	}
 }
 
@@ -3217,7 +3217,7 @@
 	struct cftype *cft;
 
 	for (cft = cfts; cft && cft->name[0] != '\0'; cft++)
-		cft->flags |= CFTYPE_ONLY_ON_DFL;
+		cft->flags |= __CFTYPE_ONLY_ON_DFL;
 	return cgroup_add_cftypes(ss, cfts);
 }
 
@@ -3234,7 +3234,7 @@
 	struct cftype *cft;
 
 	for (cft = cfts; cft && cft->name[0] != '\0'; cft++)
-		cft->flags |= CFTYPE_INSANE;
+		cft->flags |= __CFTYPE_NOT_ON_DFL;
 	return cgroup_add_cftypes(ss, cfts);
 }