[PATCH v6 1/6] perf/cgroup: Reorder perf_cgroup_connect()

[Ian Rogers]

From: Peter Zijlstra <peterz@xxxxxxxxxxxxx>

Move perf_cgroup_connect() after perf_event_alloc(), such that we can
find/use the PMU's cpu context.
Signed-off-by: Peter Zijlstra (Intel) <peterz@xxxxxxxxxxxxx>
Signed-off-by: Ian Rogers <irogers@xxxxxxxxxx>
---
 kernel/events/core.c | 16 ++++++++--------
 1 file changed, 8 insertions(+), 8 deletions(-)

diff --git a/kernel/events/core.c b/kernel/events/core.c
index 3f1f77de7247..9bd2af954c54 100644
--- a/kernel/events/core.c
+++ b/kernel/events/core.c
@@ -10804,12 +10804,6 @@ perf_event_alloc(struct perf_event_attr *attr, int cpu,
 	if (!has_branch_stack(event))
 		event->attr.branch_sample_type = 0;
 
-	if (cgroup_fd != -1) {
-		err = perf_cgroup_connect(cgroup_fd, event, attr, group_leader);
-		if (err)
-			goto err_ns;
-	}
-
 	pmu = perf_init_event(event);
 	if (IS_ERR(pmu)) {
 		err = PTR_ERR(pmu);
@@ -10831,6 +10825,12 @@ perf_event_alloc(struct perf_event_attr *attr, int cpu,
 		goto err_pmu;
 	}
 
+	if (cgroup_fd != -1) {
+		err = perf_cgroup_connect(cgroup_fd, event, attr, group_leader);
+		if (err)
+			goto err_pmu;
+	}
+
 	err = exclusive_event_init(event);
 	if (err)
 		goto err_pmu;
@@ -10891,12 +10891,12 @@ perf_event_alloc(struct perf_event_attr *attr, int cpu,
 	exclusive_event_destroy(event);
 
 err_pmu:
+	if (is_cgroup_event(event))
+		perf_detach_cgroup(event);
 	if (event->destroy)
 		event->destroy(event);
 	module_put(pmu->module);
 err_ns:
-	if (is_cgroup_event(event))
-		perf_detach_cgroup(event);
 	if (event->ns)
 		put_pid_ns(event->ns);
 	if (event->hw.target)
-- 
2.25.0.265.gbab2e86ba0-goog