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Commit d39ea871 authored by Tejun Heo's avatar Tejun Heo
Browse files

Merge branch 'for-3.16' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/percpu into for-3.16 



Pull to receive percpu_ref_tryget[_live]() changes.  Planned cgroup
changes will make use of them.

Signed-off-by: default avatarTejun Heo <tj@kernel.org>
parents 2b53f41f 4fb6e250

include/linux/cgroup.h

+1 −1
Original line number Diff line number Diff line
@@ -108,7 +108,7 @@ static inline bool css_tryget(struct cgroup_subsys_state *css) 
{

	if (css->flags & CSS_ROOT)

		return true;

	return percpu_ref_tryget(&css->refcnt);

	return percpu_ref_tryget_live(&css->refcnt);

}



/**

include/linux/percpu-refcount.h

+33 −1
Original line number Diff line number Diff line
@@ -121,6 +121,36 @@ static inline void percpu_ref_get(struct percpu_ref *ref) 
 * percpu_ref_tryget - try to increment a percpu refcount

 * @ref: percpu_ref to try-get

 *

 * Increment a percpu refcount unless its count already reached zero.

 * Returns %true on success; %false on failure.

 *

 * The caller is responsible for ensuring that @ref stays accessible.

 */

static inline bool percpu_ref_tryget(struct percpu_ref *ref)

{

	unsigned __percpu *pcpu_count;

	int ret = false;



	rcu_read_lock_sched();



	pcpu_count = ACCESS_ONCE(ref->pcpu_count);



	if (likely(REF_STATUS(pcpu_count) == PCPU_REF_PTR)) {

		__this_cpu_inc(*pcpu_count);

		ret = true;

	} else {

		ret = atomic_inc_not_zero(&ref->count);

	}



	rcu_read_unlock_sched();



	return ret;

}



/**

 * percpu_ref_tryget_live - try to increment a live percpu refcount

 * @ref: percpu_ref to try-get

 *

 * Increment a percpu refcount unless it has already been killed.  Returns

 * %true on success; %false on failure.

 *
@@ -128,8 +158,10 @@ static inline void percpu_ref_get(struct percpu_ref *ref) 
 * will fail.  For such guarantee, percpu_ref_kill_and_confirm() should be

 * used.  After the confirm_kill callback is invoked, it's guaranteed that

 * no new reference will be given out by percpu_ref_tryget().

 *

 * The caller is responsible for ensuring that @ref stays accessible.

 */

static inline bool percpu_ref_tryget(struct percpu_ref *ref)

static inline bool percpu_ref_tryget_live(struct percpu_ref *ref)

{

	unsigned __percpu *pcpu_count;

	int ret = false;

include/linux/percpu.h

+1 −1
Original line number Diff line number Diff line
@@ -29,7 +29,7 @@ 
 */

#define get_cpu_var(var) (*({				\

	preempt_disable();				\

	&__get_cpu_var(var); }))

	this_cpu_ptr(&var); }))



/*

 * The weird & is necessary because sparse considers (void)(var) to be