From 5de0107e634ce862f16360139709d9d3a656463e Mon Sep 17 00:00:00 2001 From: Tejun Heo Date: Wed, 12 Jun 2013 21:04:52 -0700 Subject: cgroup: clean up css_[try]get() and css_put() * __css_get() isn't used by anyone. Fold it into css_get(). * Add proper function comments to all css reference functions. This patch is purely cosmetic. v2: Typo fix as per Li. Signed-off-by: Tejun Heo Acked-by: Li Zefan --- include/linux/cgroup.h | 48 ++++++++++++++++++++++++------------------------ 1 file changed, 24 insertions(+), 24 deletions(-) (limited to 'include/linux/cgroup.h') diff --git a/include/linux/cgroup.h b/include/linux/cgroup.h index 0e32855edc9..a494636a34d 100644 --- a/include/linux/cgroup.h +++ b/include/linux/cgroup.h @@ -94,33 +94,31 @@ enum { CSS_ONLINE = (1 << 1), /* between ->css_online() and ->css_offline() */ }; -/* Caller must verify that the css is not for root cgroup */ -static inline void __css_get(struct cgroup_subsys_state *css, int count) -{ - atomic_add(count, &css->refcnt); -} - -/* - * Call css_get() to hold a reference on the css; it can be used - * for a reference obtained via: - * - an existing ref-counted reference to the css - * - task->cgroups for a locked task +/** + * css_get - obtain a reference on the specified css + * @css: target css + * + * The caller must already have a reference. */ - static inline void css_get(struct cgroup_subsys_state *css) { /* We don't need to reference count the root state */ if (!(css->flags & CSS_ROOT)) - __css_get(css, 1); + atomic_inc(&css->refcnt); } -/* - * Call css_tryget() to take a reference on a css if your existing - * (known-valid) reference isn't already ref-counted. Returns false if - * the css has been destroyed. - */ - extern bool __css_tryget(struct cgroup_subsys_state *css); + +/** + * css_tryget - try to obtain a reference on the specified css + * @css: target css + * + * Obtain a reference on @css if it's alive. The caller naturally needs to + * ensure that @css is accessible but doesn't have to be holding a + * reference on it - IOW, RCU protected access is good enough for this + * function. Returns %true if a reference count was successfully obtained; + * %false otherwise. + */ static inline bool css_tryget(struct cgroup_subsys_state *css) { if (css->flags & CSS_ROOT) @@ -128,12 +126,14 @@ static inline bool css_tryget(struct cgroup_subsys_state *css) return __css_tryget(css); } -/* - * css_put() should be called to release a reference taken by - * css_get() or css_tryget() - */ - extern void __css_put(struct cgroup_subsys_state *css); + +/** + * css_put - put a css reference + * @css: target css + * + * Put a reference obtained via css_get() and css_tryget(). + */ static inline void css_put(struct cgroup_subsys_state *css) { if (!(css->flags & CSS_ROOT)) -- cgit v1.2.3-70-g09d2