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| author | Tejun Heo <tj@kernel.org> | 2013-06-12 20:52:01 -0700 |
|---|---|---|
| committer | Tejun Heo <tj@kernel.org> | 2013-06-13 11:08:26 -0700 |
| commit | acac7883ee7bcc32476963bce7baf73d44574dd1 (patch) | |
| tree | 1ac595ff0f048b4beb74fd59819233b066c2d2f2 | |
| parent | ac899061a93250c28562f05ad94d5c74603415bc (diff) | |
| download | blackbird-op-linux-acac7883ee7bcc32476963bce7baf73d44574dd1.tar.gz blackbird-op-linux-acac7883ee7bcc32476963bce7baf73d44574dd1.zip | |
percpu-refcount: add __must_check to percpu_ref_init() and don't use ACCESS_ONCE() in percpu_ref_kill_rcu()
Two small changes.
* Unlike most init functions, percpu_ref_init() allocates memory and
may fail. Let's mark it with __must_check in case the caller
forgets.
* percpu_ref_kill_rcu() is unnecessarily using ACCESS_ONCE() to
dereference @ref->pcpu_count, which can be misleading. The pointer
is guaranteed to be valid and visible and can't change underneath
the function. Drop ACCESS_ONCE().
Signed-off-by: Tejun Heo <tj@kernel.org>
| -rw-r--r-- | include/linux/percpu-refcount.h | 3 | ||||
| -rw-r--r-- | lib/percpu-refcount.c | 4 |
2 files changed, 3 insertions, 4 deletions
diff --git a/include/linux/percpu-refcount.h b/include/linux/percpu-refcount.h index b61bd6f23985..8146aa9cd89e 100644 --- a/include/linux/percpu-refcount.h +++ b/include/linux/percpu-refcount.h @@ -66,7 +66,8 @@ struct percpu_ref { struct rcu_head rcu; }; -int percpu_ref_init(struct percpu_ref *ref, percpu_ref_func_t *release); +int __must_check percpu_ref_init(struct percpu_ref *ref, + percpu_ref_func_t *release); void percpu_ref_kill(struct percpu_ref *ref); #define PCPU_STATUS_BITS 2 diff --git a/lib/percpu-refcount.c b/lib/percpu-refcount.c index 9a78e55fa48f..b35eaac2954f 100644 --- a/lib/percpu-refcount.c +++ b/lib/percpu-refcount.c @@ -57,12 +57,10 @@ int percpu_ref_init(struct percpu_ref *ref, percpu_ref_func_t *release) static void percpu_ref_kill_rcu(struct rcu_head *rcu) { struct percpu_ref *ref = container_of(rcu, struct percpu_ref, rcu); - unsigned __percpu *pcpu_count; + unsigned __percpu *pcpu_count = ref->pcpu_count; unsigned count = 0; int cpu; - pcpu_count = ACCESS_ONCE(ref->pcpu_count); - /* Mask out PCPU_REF_DEAD */ pcpu_count = (unsigned __percpu *) (((unsigned long) pcpu_count) & ~PCPU_STATUS_MASK); |
