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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 <tj@kernel.org>
Acked-by: Li Zefan <lizefan@huawei.com>
This commit is contained in:
Tejun Heo 2013-06-12 21:04:52 -07:00
parent f4f4be2bd2
commit 5de0107e63
1 changed files with 24 additions and 24 deletions
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48
include/linux/cgroup.h
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@ -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))