[RFC PATCH 05/27] mm/damon/sysfs: add reports/producers/ directory

[SJ Park <sj@kernel.org>]

Add a new sysfs directory, producers/, under reports/ directory.  It is
a placeholder for files that will be used for controlling DAMON report
producers.

Signed-off-by: SJ Park <sj@kernel.org>
---
 mm/damon/sysfs.c | 48 +++++++++++++++++++++++++++++++++++++++++++++++-
 1 file changed, 47 insertions(+), 1 deletion(-)

diff --git a/mm/damon/sysfs.c b/mm/damon/sysfs.c
index 76850a4b5b5a7..75701ed662222 100644
--- a/mm/damon/sysfs.c
+++ b/mm/damon/sysfs.c
@@ -2979,10 +2979,38 @@ static const struct kobj_type damon_sysfs_kdamonds_ktype = {
 	.default_groups = damon_sysfs_kdamonds_groups,
 };
 
+/* producers dir */
+
+struct damon_sysfs_producers {
+	struct kobject kobj;
+};
+
+static struct damon_sysfs_producers *damon_sysfs_producers_alloc(void)
+{
+	return kzalloc_obj(struct damon_sysfs_producers);
+}
+
+static void damon_sysfs_producers_release(struct kobject *kobj)
+{
+	kfree(container_of(kobj, struct damon_sysfs_producers, kobj));
+}
+
+static struct attribute *damon_sysfs_producers_attrs[] = {
+	NULL,
+};
+ATTRIBUTE_GROUPS(damon_sysfs_producers);
+
+static const struct kobj_type damon_sysfs_producers_ktype = {
+	.release = damon_sysfs_producers_release,
+	.sysfs_ops = &kobj_sysfs_ops,
+	.default_groups = damon_sysfs_producers_groups,
+};
+
 /* reports dir */
 
 struct damon_sysfs_reports {
 	struct kobject kobj;
+	struct damon_sysfs_producers *producers;
 };
 
 static struct damon_sysfs_reports *damon_sysfs_reports_alloc(void)
@@ -2992,7 +3020,25 @@ static struct damon_sysfs_reports *damon_sysfs_reports_alloc(void)
 
 static int damon_sysfs_reports_add_dirs(struct damon_sysfs_reports *reports)
 {
-	return 0;
+	struct damon_sysfs_producers *producers;
+	int err;
+
+	producers = damon_sysfs_producers_alloc();
+	if (!producers)
+		return -ENOMEM;
+	reports->producers = producers;
+
+	err = kobject_init_and_add(&producers->kobj,
+			&damon_sysfs_producers_ktype, &reports->kobj,
+			"producers");
+	if (err)
+		goto put_producers_out;
+	return err;
+
+put_producers_out:
+	kobject_put(&producers->kobj);
+	reports->producers = NULL;
+	return err;
 }
 
 static void damon_sysfs_reports_release(struct kobject *kobj)
-- 
2.47.3