From 38b53abaa3e0c7e750ef73eee919cf42eee6b134 Mon Sep 17 00:00:00 2001 From: Tejun Heo 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 Acked-by: Li Zefan --- 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 d605857c4bf3..a0fc64167129 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 affc76d7f739..82ad8785fafe 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;