[PATCH 05/13] perf: Simplify perf_cgroup_connect()

Peter Zijlstra
2023-11-02T15:33:19Z

Use CLASS to reduce gotos and simplify control flow.

Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
---
include/linux/file.h | 2 +-
kernel/events/core.c | 19 ++++++++-----------
2 files changed, 9 insertions(+), 12 deletions(-)

--- a/kernel/events/core.c
+++ b/kernel/events/core.c
@@ -936,22 +936,20 @@ static inline int perf_cgroup_connect(in
{
struct perf_cgroup *cgrp;
struct cgroup_subsys_state *css;
- struct fd f = fdget(fd);
- int ret = 0;
+ int ret;

+ CLASS(fd, f)(fd);
if (!f.file)
return -EBADF;

css = css_tryget_online_from_dir(f.file->f_path.dentry,
&perf_event_cgrp_subsys);
- if (IS_ERR(css)) {
- ret = PTR_ERR(css);
- goto out;
- }
+ if (IS_ERR(css))
+ return PTR_ERR(css);

ret = perf_cgroup_ensure_storage(event, css);
if (ret)
- goto out;
+ return ret;

cgrp = container_of(css, struct perf_cgroup, css);
event->cgrp = cgrp;
@@ -963,11 +961,10 @@ static inline int perf_cgroup_connect(in
*/
if (group_leader && group_leader->cgrp != cgrp) {
perf_detach_cgroup(event);
- ret = -EINVAL;
+ return -EINVAL;
}
-out:
- fdput(f);
- return ret;
+
+ return 0;
}

static inline void