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| author | Tejun Heo <tj@kernel.org> | 2013-06-13 07:43:06 +0400 |
|---|---|---|
| committer | Tejun Heo <tj@kernel.org> | 2013-06-13 07:43:06 +0400 |
| commit | 6a24474da83ea7c8b7d32f05f858b1259994067a (patch) | |
| tree | 88633b53318c1adb8f648eaf5edcabac8f81b01b /include/linux/percpu-refcount.h | |
| parent | c1ae6e9b4db00023b9caed72af49a93abad46452 (diff) | |
| download | linux-6a24474da83ea7c8b7d32f05f858b1259994067a.tar.xz | |
percpu-refcount: consistently use plain (non-sched) RCU
percpu_ref_get/put() are using preempt_disable/enable() while
percpu_ref_kill() is using plain call_rcu() instead of
call_rcu_sched(). This is buggy as grace periods of the two may not
match. Fix it by using plain RCU in percpu_ref_get/put().
(I suggested using sched RCU in the first place but there's no actual
benefit in doing so unless we're gonna introduce different variants
of get/put to be called while preemption is alredy disabled, which we
definitely shouldn't.)
Signed-off-by: Tejun Heo <tj@kernel.org>
Reported-by: Rusty Russell <rusty@rustcorp.com.au>
Acked-by: Kent Overstreet <koverstreet@google.com>
Diffstat (limited to 'include/linux/percpu-refcount.h')
| -rw-r--r-- | include/linux/percpu-refcount.h | 8 |
1 files changed, 4 insertions, 4 deletions
diff --git a/include/linux/percpu-refcount.h b/include/linux/percpu-refcount.h index 24b31ef15932..abe141172d96 100644 --- a/include/linux/percpu-refcount.h +++ b/include/linux/percpu-refcount.h @@ -85,7 +85,7 @@ static inline void percpu_ref_get(struct percpu_ref *ref) { unsigned __percpu *pcpu_count; - preempt_disable(); + rcu_read_lock(); pcpu_count = ACCESS_ONCE(ref->pcpu_count); @@ -94,7 +94,7 @@ static inline void percpu_ref_get(struct percpu_ref *ref) else atomic_inc(&ref->count); - preempt_enable(); + rcu_read_unlock(); } /** @@ -107,7 +107,7 @@ static inline void percpu_ref_put(struct percpu_ref *ref) { unsigned __percpu *pcpu_count; - preempt_disable(); + rcu_read_lock(); pcpu_count = ACCESS_ONCE(ref->pcpu_count); @@ -116,7 +116,7 @@ static inline void percpu_ref_put(struct percpu_ref *ref) else if (unlikely(atomic_dec_and_test(&ref->count))) ref->release(ref); - preempt_enable(); + rcu_read_unlock(); } #endif |