diff options
| -rw-r--r-- | kernel/events/core.c | 28 |
1 files changed, 26 insertions, 2 deletions
diff --git a/kernel/events/core.c b/kernel/events/core.c index 11793d690cbb..823aa0824916 100644 --- a/kernel/events/core.c +++ b/kernel/events/core.c @@ -11830,6 +11830,21 @@ free_dev: static struct lock_class_key cpuctx_mutex; static struct lock_class_key cpuctx_lock; +static bool idr_cmpxchg(struct idr *idr, unsigned long id, void *old, void *new) +{ + void *tmp, *val = idr_find(idr, id); + + if (val != old) + return false; + + tmp = idr_replace(idr, new, id); + if (IS_ERR(tmp)) + return false; + + WARN_ON_ONCE(tmp != val); + return true; +} + int perf_pmu_register(struct pmu *pmu, const char *name, int type) { int cpu, ret, max = PERF_TYPE_MAX; @@ -11856,7 +11871,7 @@ int perf_pmu_register(struct pmu *pmu, const char *name, int type) if (type >= 0) max = type; - ret = idr_alloc(&pmu_idr, pmu, max, 0, GFP_KERNEL); + ret = idr_alloc(&pmu_idr, NULL, max, 0, GFP_KERNEL); if (ret < 0) goto free_pdc; @@ -11864,6 +11879,7 @@ int perf_pmu_register(struct pmu *pmu, const char *name, int type) type = ret; pmu->type = type; + atomic_set(&pmu->exclusive_cnt, 0); if (pmu_bus_running && !pmu->dev) { ret = pmu_dev_alloc(pmu); @@ -11912,14 +11928,22 @@ int perf_pmu_register(struct pmu *pmu, const char *name, int type) if (!pmu->event_idx) pmu->event_idx = perf_event_idx_default; + /* + * Now that the PMU is complete, make it visible to perf_try_init_event(). + */ + if (!idr_cmpxchg(&pmu_idr, pmu->type, NULL, pmu)) + goto free_context; list_add_rcu(&pmu->entry, &pmus); - atomic_set(&pmu->exclusive_cnt, 0); + ret = 0; unlock: mutex_unlock(&pmus_lock); return ret; +free_context: + free_percpu(pmu->cpu_pmu_context); + free_dev: if (pmu->dev && pmu->dev != PMU_NULL_DEV) { device_del(pmu->dev); |