Commit 494eaf46 authored Mar 02, 2026 by zhidao su Committed by Tejun Heo Mar 02, 2026

sched_ext: Replace naked scx_root dereferences in kobject callbacks



scx_attr_ops_show() and scx_uevent() access scx_root->ops.name directly.
This is problematic for two reasons:

1. The file-level comment explicitly identifies naked scx_root
   dereferences as a temporary measure that needs to be replaced
   with proper per-instance access.

2. scx_attr_events_show(), the neighboring sysfs show function in
   the same group, already uses the correct pattern:

       struct scx_sched *sch = container_of(kobj, struct scx_sched, kobj);

   Having inconsistent access patterns in the same sysfs/uevent
   group is error-prone.

The kobject embedded in struct scx_sched is initialized as:

    kobject_init_and_add(&sch->kobj, &scx_ktype, NULL, "root");

so container_of(kobj, struct scx_sched, kobj) correctly retrieves
the owning scx_sched instance in both callbacks.

Replace the naked scx_root dereferences with container_of()-based
access, consistent with scx_attr_events_show() and in preparation
for proper multi-instance scx_sched support.

Signed-off-by: zhidao su <suzhidao@xiaomi.com>
Signed-off-by: Tejun Heo <tj@kernel.org>

parent 9adfcef3

kernel/sched/ext.c

+6 −2

Original line number	Diff line number	Diff line
		@@ -3712,7 +3712,9 @@ static void scx_kobj_release(struct kobject *kobj)
		static ssize_t scx_attr_ops_show(struct kobject *kobj,
		struct kobj_attribute ka, char buf)
		{
		return sysfs_emit(buf, "%s\n", scx_root->ops.name);
		struct scx_sched *sch = container_of(kobj, struct scx_sched, kobj);

		return sysfs_emit(buf, "%s\n", sch->ops.name);
		}
		SCX_ATTR(ops);

		@@ -3756,7 +3758,9 @@ static const struct kobj_type scx_ktype = {

		static int scx_uevent(const struct kobject kobj, struct kobj_uevent_env env)
		{
		return add_uevent_var(env, "SCXOPS=%s", scx_root->ops.name);
		const struct scx_sched *sch = container_of(kobj, struct scx_sched, kobj);

		return add_uevent_var(env, "SCXOPS=%s", sch->ops.name);
		}

		static const struct kset_uevent_ops scx_uevent_ops = {