Merge branch 'for-3.15-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/percpu.git into for-3.16
Pull percpu/for-3.15-fixes into percpu/for-3.16 to receive
0c36b390a546 ("percpu-refcount: fix usage of this_cpu_ops").
The merge doesn't produce any conflict but the automatic merge is
still incorrect because 4fb6e25049cb ("percpu-refcount: implement
percpu_ref_tryget()") added another use of __this_cpu_inc() which
should also be converted to this_cpu_ince().
This commit pulls in percpu/for-3.15-fixes and converts the newly
added __this_cpu_inc() to this_cpu_inc().
Signed-off-by: Tejun Heo <tj@kernel.org>
diff --git a/include/linux/cgroup.h b/include/linux/cgroup.h
index c251585..549aed8 100644
--- a/include/linux/cgroup.h
+++ b/include/linux/cgroup.h
@@ -101,7 +101,7 @@
{
if (css->flags & CSS_ROOT)
return true;
- return percpu_ref_tryget(&css->refcnt);
+ return percpu_ref_tryget_live(&css->refcnt);
}
/**
diff --git a/include/linux/percpu-refcount.h b/include/linux/percpu-refcount.h
index 0afb48f..5d8920e 100644
--- a/include/linux/percpu-refcount.h
+++ b/include/linux/percpu-refcount.h
@@ -121,6 +121,36 @@
* 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 @@
* 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;
diff --git a/include/linux/percpu.h b/include/linux/percpu.h
index e7a0b95..539b3ca 100644
--- a/include/linux/percpu.h
+++ b/include/linux/percpu.h
@@ -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