From: Robert Richter robert.richter@linaro.org
We need this later for proper event removal.
Signed-off-by: Robert Richter robert.richter@linaro.org Signed-off-by: Robert Richter rric@kernel.org --- kernel/events/persistent.c | 27 +++++++++++++++++---------- 1 file changed, 17 insertions(+), 10 deletions(-)
diff --git a/kernel/events/persistent.c b/kernel/events/persistent.c index f23270b..70446ae 100644 --- a/kernel/events/persistent.c +++ b/kernel/events/persistent.c @@ -9,6 +9,7 @@ #define CPU_BUFFER_NR_PAGES ((512 * 1024) / PAGE_SIZE)
struct pevent { + atomic_t refcount; struct perf_pmu_events_attr sysfs; char *name; int id; @@ -130,6 +131,7 @@ static int persistent_event_open(int cpu, struct pevent *pevent, if (ret) goto fail;
+ atomic_inc(&pevent->refcount); atomic_inc(&event->mmap_count);
/* All workie, enable event now */ @@ -144,8 +146,11 @@ static int persistent_event_open(int cpu, struct pevent *pevent, static void persistent_event_close(int cpu, struct pevent *pevent) { struct perf_event *event = pevent_del(pevent, cpu); - if (event) + if (event) { + /* Safe, the caller holds &pevent->refcount too. */ + atomic_dec(&pevent->refcount); persistent_event_release(event); + } }
static int pevent_sysfs_register(struct pevent *event); @@ -162,6 +167,8 @@ persistent_open(char *name, struct perf_event_attr *attr, int nr_pages) if (!pevent) return -ENOMEM;
+ atomic_set(&pevent->refcount, 1); + ret = get_event_id(pevent); if (ret < 0) goto fail; @@ -187,21 +194,21 @@ persistent_open(char *name, struct perf_event_attr *attr, int nr_pages) }
ret = pevent_sysfs_register(pevent); - if (ret) - goto fail; - - return 0; + if (!ret) + goto out; fail: for_each_possible_cpu(cpu) persistent_event_close(cpu, pevent);
- if (pevent->id) - put_event_id(pevent->id); - kfree(pevent->name); - kfree(pevent); - pr_err("%s: Error adding persistent event: %d\n", __func__, ret); +out: + if (atomic_dec_and_test(&pevent->refcount)) { + if (pevent->id) + put_event_id(pevent->id); + kfree(pevent->name); + kfree(pevent); + }
return ret; }