From 6304c879b820ef889a7f2516a1d1c08dd18d9579 Mon Sep 17 00:00:00 2001
From: Tejun Heo <tj@kernel.org>
Date: Mon, 19 Nov 2012 08:13:36 -0800
Subject: [PATCH] cgroup: make CSS_* flags bit masks instead of bit positions
Currently, CSS_* flags are defined as bit positions and manipulated
using atomic bitops. There's no reason to use atomic bitops for them
and bit positions are clunkier to deal with than bit masks. Make
CSS_* bit masks instead and use the usual C bitwise operators to
access them.
Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Li Zefan <lizefan@huawei.com>
---
include/linux/cgroup.h | 8 ++++----
kernel/cgroup.c | 2 +-
2 files changed, 5 insertions(+), 5 deletions(-)
diff --git a/include/linux/cgroup.h b/include/linux/cgroup.h
index d605857c4bf37..a0fc64167129d 100644
--- a/include/linux/cgroup.h
+++ b/include/linux/cgroup.h
@@ -81,7 +81,7 @@ struct cgroup_subsys_state {
/* bits in struct cgroup_subsys_state flags field */
enum {
- CSS_ROOT, /* This CSS is the root of the subsystem */
+ CSS_ROOT = (1 << 0), /* this CSS is the root of the subsystem */
};
/* Caller must verify that the css is not for root cgroup */
@@ -100,7 +100,7 @@ static inline void __css_get(struct cgroup_subsys_state *css, int count)
static inline void css_get(struct cgroup_subsys_state *css)
{
/* We don't need to reference count the root state */
- if (!test_bit(CSS_ROOT, &css->flags))
+ if (!(css->flags & CSS_ROOT))
__css_get(css, 1);
}
@@ -113,7 +113,7 @@ static inline void css_get(struct cgroup_subsys_state *css)
extern bool __css_tryget(struct cgroup_subsys_state *css);
static inline bool css_tryget(struct cgroup_subsys_state *css)
{
- if (test_bit(CSS_ROOT, &css->flags))
+ if (css->flags & CSS_ROOT)
return true;
return __css_tryget(css);
}
@@ -126,7 +126,7 @@ static inline bool css_tryget(struct cgroup_subsys_state *css)
extern void __css_put(struct cgroup_subsys_state *css);
static inline void css_put(struct cgroup_subsys_state *css)
{
- if (!test_bit(CSS_ROOT, &css->flags))
+ if (!(css->flags & CSS_ROOT))
__css_put(css);
}
diff --git a/kernel/cgroup.c b/kernel/cgroup.c
index affc76d7f739a..82ad8785fafe5 100644
--- a/kernel/cgroup.c
+++ b/kernel/cgroup.c
@@ -4020,7 +4020,7 @@ static void init_cgroup_css(struct cgroup_subsys_state *css,
css->flags = 0;
css->id = NULL;
if (cgrp == dummytop)
- set_bit(CSS_ROOT, &css->flags);
+ css->flags |= CSS_ROOT;
BUG_ON(cgrp->subsys[ss->subsys_id]);
cgrp->subsys[ss->subsys_id] = css;
--
2.39.5