diff options
| -rw-r--r-- | include/linux/percpu-refcount.h | 1 | ||||
| -rw-r--r-- | lib/percpu-refcount.c | 31 |
2 files changed, 32 insertions, 0 deletions
diff --git a/include/linux/percpu-refcount.h b/include/linux/percpu-refcount.h index 8146aa9cd89e..6d843d60690d 100644 --- a/include/linux/percpu-refcount.h +++ b/include/linux/percpu-refcount.h @@ -68,6 +68,7 @@ struct percpu_ref { int __must_check percpu_ref_init(struct percpu_ref *ref, percpu_ref_func_t *release); +void percpu_ref_cancel_init(struct percpu_ref *ref); 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 b35eaac2954f..ebeaac274cb9 100644 --- a/lib/percpu-refcount.c +++ b/lib/percpu-refcount.c @@ -54,6 +54,37 @@ int percpu_ref_init(struct percpu_ref *ref, percpu_ref_func_t *release) return 0; } +/** + * percpu_ref_cancel_init - cancel percpu_ref_init() + * @ref: percpu_ref to cancel init for + * + * Once a percpu_ref is initialized, its destruction is initiated by + * percpu_ref_kill() and completes asynchronously, which can be painful to + * do when destroying a half-constructed object in init failure path. + * + * This function destroys @ref without invoking @ref->release and the + * memory area containing it can be freed immediately on return. To + * prevent accidental misuse, it's required that @ref has finished + * percpu_ref_init(), whether successful or not, but never used. + * + * The weird name and usage restriction are to prevent people from using + * this function by mistake for normal shutdown instead of + * percpu_ref_kill(). + */ +void percpu_ref_cancel_init(struct percpu_ref *ref) +{ + unsigned __percpu *pcpu_count = ref->pcpu_count; + int cpu; + + WARN_ON_ONCE(atomic_read(&ref->count) != 1 + PCPU_COUNT_BIAS); + + if (pcpu_count) { + for_each_possible_cpu(cpu) + WARN_ON_ONCE(*per_cpu_ptr(pcpu_count, cpu)); + free_percpu(ref->pcpu_count); + } +} + static void percpu_ref_kill_rcu(struct rcu_head *rcu) { struct percpu_ref *ref = container_of(rcu, struct percpu_ref, rcu); |