[RFC PATCH 04/27] mm/damon/sysfs: add admin/reports/ directory

[SJ Park <sj@kernel.org>]

Add a new sysfs directory, reports/, as a place holder for sysfs files
that will be used for controlling the data attribute report system.  Put
the directory under the admin/ directory, next to kdamonds/ directory.

Signed-off-by: SJ Park <sj@kernel.org>
---
 mm/damon/sysfs.c | 63 +++++++++++++++++++++++++++++++++++++++++++++---
 1 file changed, 59 insertions(+), 4 deletions(-)

diff --git a/mm/damon/sysfs.c b/mm/damon/sysfs.c
index 779c98205a94b..76850a4b5b5a7 100644
--- a/mm/damon/sysfs.c
+++ b/mm/damon/sysfs.c
@@ -2979,6 +2979,38 @@ static const struct kobj_type damon_sysfs_kdamonds_ktype = {
 	.default_groups = damon_sysfs_kdamonds_groups,
 };
 
+/* reports dir */
+
+struct damon_sysfs_reports {
+	struct kobject kobj;
+};
+
+static struct damon_sysfs_reports *damon_sysfs_reports_alloc(void)
+{
+	return kzalloc_obj(struct damon_sysfs_reports);
+}
+
+static int damon_sysfs_reports_add_dirs(struct damon_sysfs_reports *reports)
+{
+	return 0;
+}
+
+static void damon_sysfs_reports_release(struct kobject *kobj)
+{
+	kfree(container_of(kobj, struct damon_sysfs_reports, kobj));
+}
+
+static struct attribute *damon_sysfs_reports_attrs[] = {
+	NULL,
+};
+ATTRIBUTE_GROUPS(damon_sysfs_reports);
+
+static const struct kobj_type damon_sysfs_reports_ktype = {
+	.release = damon_sysfs_reports_release,
+	.sysfs_ops = &kobj_sysfs_ops,
+	.default_groups = damon_sysfs_reports_groups,
+};
+
 /*
  * damon user interface directory
  */
@@ -2986,6 +3018,7 @@ static const struct kobj_type damon_sysfs_kdamonds_ktype = {
 struct damon_sysfs_ui_dir {
 	struct kobject kobj;
 	struct damon_sysfs_kdamonds *kdamonds;
+	struct damon_sysfs_reports *reports;
 };
 
 static struct damon_sysfs_ui_dir *damon_sysfs_ui_dir_alloc(void)
@@ -2996,6 +3029,7 @@ static struct damon_sysfs_ui_dir *damon_sysfs_ui_dir_alloc(void)
 static int damon_sysfs_ui_dir_add_dirs(struct damon_sysfs_ui_dir *ui_dir)
 {
 	struct damon_sysfs_kdamonds *kdamonds;
+	struct damon_sysfs_reports *reports;
 	int err;
 
 	kdamonds = damon_sysfs_kdamonds_alloc();
@@ -3005,11 +3039,32 @@ static int damon_sysfs_ui_dir_add_dirs(struct damon_sysfs_ui_dir *ui_dir)
 	err = kobject_init_and_add(&kdamonds->kobj,
 			&damon_sysfs_kdamonds_ktype, &ui_dir->kobj,
 			"kdamonds");
-	if (err) {
-		kobject_put(&kdamonds->kobj);
-		return err;
-	}
+	if (err)
+		goto put_kdamonds_out;
 	ui_dir->kdamonds = kdamonds;
+
+	reports = damon_sysfs_reports_alloc();
+	if (!reports) {
+		err = -ENOMEM;
+		goto put_kdamonds_out;
+	}
+	ui_dir->reports = reports;
+
+	err = kobject_init_and_add(&reports->kobj, &damon_sysfs_reports_ktype,
+			&ui_dir->kobj, "reports");
+	if (err)
+		goto put_reports_out;
+	err = damon_sysfs_reports_add_dirs(reports);
+	if (err)
+		goto put_reports_out;
+	return err;
+
+put_reports_out:
+	kobject_put(&reports->kobj);
+	ui_dir->reports = NULL;
+put_kdamonds_out:
+	kobject_put(&kdamonds->kobj);
+	ui_dir->kdamonds = NULL;
 	return err;
 }
 
-- 
2.47.3