1 files changed, 4 insertions, 21 deletions

diff --git a/kernel/events/core.c b/kernel/events/core.c
index 661951ab8ae7..f83a71a3e46d 100644
--- a/kernel/events/core.c
+++ b/kernel/events/core.c
@@ -361,7 +361,7 @@ struct perf_cgroup {
 static inline struct perf_cgroup *
 perf_cgroup_from_task(struct task_struct *task)
 {
-        return container_of(task_css(task, perf_subsys_id),
+        return container_of(task_css(task, perf_event_cgrp_id),
                             struct perf_cgroup, css);
 }
 
@@ -389,11 +389,6 @@ perf_cgroup_match(struct perf_event *event)
                                     event->cgrp->css.cgroup);
 }
 
-static inline bool perf_tryget_cgroup(struct perf_event *event)
-{
-        return css_tryget(&event->cgrp->css);
-}
-
 static inline void perf_put_cgroup(struct perf_event *event)
 {
         css_put(&event->cgrp->css);
@@ -612,9 +607,7 @@ static inline int perf_cgroup_connect(int fd, struct perf_event *event,
         if (!f.file)
                 return -EBADF;
 
-        rcu_read_lock();
-
-        css = css_from_dir(f.file->f_dentry, &perf_subsys);
+        css = css_tryget_from_dir(f.file->f_dentry, &perf_event_cgrp_subsys);
         if (IS_ERR(css)) {
                 ret = PTR_ERR(css);
                 goto out;
@@ -623,13 +616,6 @@ static inline int perf_cgroup_connect(int fd, struct perf_event *event,
         cgrp = container_of(css, struct perf_cgroup, css);
         event->cgrp = cgrp;
 
-        /* must be done before we fput() the file */
-        if (!perf_tryget_cgroup(event)) {
-                event->cgrp = NULL;
-                ret = -ENOENT;
-                goto out;
-        }
-
         /*
          * all events in a group must monitor
          * the same cgroup because a task belongs
@@ -640,7 +626,6 @@ static inline int perf_cgroup_connect(int fd, struct perf_event *event,
                 ret = -EINVAL;
         }
 out:
-        rcu_read_unlock();
         fdput(f);
         return ret;
 }
@@ -8053,7 +8038,7 @@ static void perf_cgroup_attach(struct cgroup_subsys_state *css,
 {
         struct task_struct *task;
 
-        cgroup_taskset_for_each(task, css, tset)
+        cgroup_taskset_for_each(task, tset)
                 task_function_call(task, __perf_cgroup_move, task);
 }
 
@@ -8072,9 +8057,7 @@ static void perf_cgroup_exit(struct cgroup_subsys_state *css,
         task_function_call(task, __perf_cgroup_move, task);
 }
 
-struct cgroup_subsys perf_subsys = {
-        .name           = "perf_event",
-        .subsys_id      = perf_subsys_id,
+struct cgroup_subsys perf_event_cgrp_subsys = {
         .css_alloc      = perf_cgroup_css_alloc,
         .css_free       = perf_cgroup_css_free,
         .exit           = perf_cgroup_exit,