diff options
| -rw-r--r-- | include/linux/percpu-refcount.h | 6 | ||||
| -rw-r--r-- | lib/percpu-refcount.c | 19 |
2 files changed, 16 insertions, 9 deletions
diff --git a/include/linux/percpu-refcount.h b/include/linux/percpu-refcount.h index 910e5f72055d..bd9483d390b4 100644 --- a/include/linux/percpu-refcount.h +++ b/include/linux/percpu-refcount.h @@ -57,6 +57,10 @@ typedef void (percpu_ref_func_t)(struct percpu_ref *); /* flags set in the lower bits of percpu_ref->percpu_count_ptr */ enum { __PERCPU_REF_ATOMIC = 1LU << 0, /* operating in atomic mode */ + __PERCPU_REF_DEAD = 1LU << 1, /* (being) killed */ + __PERCPU_REF_ATOMIC_DEAD = __PERCPU_REF_ATOMIC | __PERCPU_REF_DEAD, + + __PERCPU_REF_FLAG_BITS = 2, }; struct percpu_ref { @@ -107,7 +111,7 @@ static inline bool __ref_is_percpu(struct percpu_ref *ref, /* paired with smp_store_release() in percpu_ref_reinit() */ smp_read_barrier_depends(); - if (unlikely(percpu_ptr & __PERCPU_REF_ATOMIC)) + if (unlikely(percpu_ptr & __PERCPU_REF_ATOMIC_DEAD)) return false; *percpu_countp = (unsigned long __percpu *)percpu_ptr; diff --git a/lib/percpu-refcount.c b/lib/percpu-refcount.c index 7aef590c1ef8..e2ff19f970cf 100644 --- a/lib/percpu-refcount.c +++ b/lib/percpu-refcount.c @@ -34,7 +34,7 @@ static unsigned long __percpu *percpu_count_ptr(struct percpu_ref *ref) { return (unsigned long __percpu *) - (ref->percpu_count_ptr & ~__PERCPU_REF_ATOMIC); + (ref->percpu_count_ptr & ~__PERCPU_REF_ATOMIC_DEAD); } /** @@ -52,10 +52,13 @@ static unsigned long __percpu *percpu_count_ptr(struct percpu_ref *ref) int percpu_ref_init(struct percpu_ref *ref, percpu_ref_func_t *release, gfp_t gfp) { + size_t align = max_t(size_t, 1 << __PERCPU_REF_FLAG_BITS, + __alignof__(unsigned long)); + atomic_long_set(&ref->count, 1 + PERCPU_COUNT_BIAS); - ref->percpu_count_ptr = - (unsigned long)alloc_percpu_gfp(unsigned long, gfp); + ref->percpu_count_ptr = (unsigned long) + __alloc_percpu_gfp(sizeof(unsigned long), align, gfp); if (!ref->percpu_count_ptr) return -ENOMEM; @@ -80,7 +83,7 @@ void percpu_ref_exit(struct percpu_ref *ref) if (percpu_count) { free_percpu(percpu_count); - ref->percpu_count_ptr = __PERCPU_REF_ATOMIC; + ref->percpu_count_ptr = __PERCPU_REF_ATOMIC_DEAD; } } EXPORT_SYMBOL_GPL(percpu_ref_exit); @@ -145,10 +148,10 @@ static void percpu_ref_kill_rcu(struct rcu_head *rcu) void percpu_ref_kill_and_confirm(struct percpu_ref *ref, percpu_ref_func_t *confirm_kill) { - WARN_ONCE(ref->percpu_count_ptr & __PERCPU_REF_ATOMIC, + WARN_ONCE(ref->percpu_count_ptr & __PERCPU_REF_ATOMIC_DEAD, "%s called more than once on %pf!", __func__, ref->release); - ref->percpu_count_ptr |= __PERCPU_REF_ATOMIC; + ref->percpu_count_ptr |= __PERCPU_REF_ATOMIC_DEAD; ref->confirm_switch = confirm_kill; call_rcu_sched(&ref->rcu, percpu_ref_kill_rcu); @@ -180,12 +183,12 @@ void percpu_ref_reinit(struct percpu_ref *ref) * Restore per-cpu operation. smp_store_release() is paired with * smp_read_barrier_depends() in __ref_is_percpu() and guarantees * that the zeroing is visible to all percpu accesses which can see - * the following __PERCPU_REF_ATOMIC clearing. + * the following __PERCPU_REF_ATOMIC_DEAD clearing. */ for_each_possible_cpu(cpu) *per_cpu_ptr(percpu_count, cpu) = 0; smp_store_release(&ref->percpu_count_ptr, - ref->percpu_count_ptr & ~__PERCPU_REF_ATOMIC); + ref->percpu_count_ptr & ~__PERCPU_REF_ATOMIC_DEAD); } EXPORT_SYMBOL_GPL(percpu_ref_reinit); |