[RFC PATCH 08/27] mm/damon/sysfs: implement report producer type and state files

[SJ Park <sj@kernel.org>]

Implement report_type and producer_state files under the report producer
directory.  The type file receives the type of the reports that the
producer will generate and submit to DAMON.  The producer_state file
enables and disables the producer.

Signed-off-by: SJ Park <sj@kernel.org>
---
 mm/damon/sysfs.c | 80 ++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 80 insertions(+)

diff --git a/mm/damon/sysfs.c b/mm/damon/sysfs.c
index 7c6bc30c12125..7cdbe2fedf7d8 100644
--- a/mm/damon/sysfs.c
+++ b/mm/damon/sysfs.c
@@ -2983,6 +2983,8 @@ static const struct kobj_type damon_sysfs_kdamonds_ktype = {
 
 struct damon_sysfs_producer {
 	struct kobject kobj;
+	enum damon_report_type report_type;
+	bool enabled;
 };
 
 static struct damon_sysfs_producer *damon_sysfs_producer_alloc(void)
@@ -2990,6 +2992,77 @@ static struct damon_sysfs_producer *damon_sysfs_producer_alloc(void)
 	return kzalloc_obj(struct damon_sysfs_producer);
 }
 
+struct damon_sysfs_report_type_name {
+	enum damon_report_type type;
+	char *name;
+};
+
+static const struct damon_sysfs_report_type_name
+damon_sysfs_report_type_names[] = {
+};
+
+static ssize_t report_type_show(struct kobject *kobj,
+		struct kobj_attribute *attr, char *buf)
+{
+	struct damon_sysfs_producer *producer = container_of(kobj,
+			struct damon_sysfs_producer, kobj);
+	int i;
+
+	for (i = 0; i < ARRAY_SIZE(damon_sysfs_report_type_names); i++) {
+		const struct damon_sysfs_report_type_name *type_name;
+
+		type_name = &damon_sysfs_report_type_names[i];
+		if (type_name->type == producer->report_type)
+			return sysfs_emit(buf, "%s\n", type_name->name);
+	}
+	return -EINVAL;
+}
+
+static ssize_t report_type_store(struct kobject *kobj,
+		struct kobj_attribute *attr, const char *buf, size_t count)
+{
+	struct damon_sysfs_producer *producer = container_of(kobj,
+			struct damon_sysfs_producer, kobj);
+	ssize_t ret = -EINVAL;
+	int i;
+
+	for (i = 0; i < ARRAY_SIZE(damon_sysfs_report_type_names); i++) {
+		const struct damon_sysfs_report_type_name *type_name;
+
+		type_name = &damon_sysfs_report_type_names[i];
+		if (sysfs_streq(buf, type_name->name)) {
+			producer->report_type = type_name->type;
+			ret = count;
+			break;
+		}
+	}
+	return ret;
+}
+
+static ssize_t producer_state_show(struct kobject *kobj,
+		struct kobj_attribute *attr, char *buf)
+{
+	struct damon_sysfs_producer *producer = container_of(kobj,
+			struct damon_sysfs_producer, kobj);
+
+	return sysfs_emit(buf, "%s\n", producer->enabled ? "on" : "off");
+}
+
+static ssize_t producer_state_store(struct kobject *kobj,
+		struct kobj_attribute *attr, const char *buf, size_t count)
+{
+	struct damon_sysfs_producer *producer = container_of(kobj,
+			struct damon_sysfs_producer, kobj);
+
+	if (sysfs_streq(buf, "on"))
+		producer->enabled = true;
+	else if (sysfs_streq(buf, "off"))
+		producer->enabled = false;
+	else
+		return -EINVAL;
+	return count;
+}
+
 static void damon_sysfs_producer_release(struct kobject *kobj)
 {
 	struct damon_sysfs_producer *producer = container_of(kobj,
@@ -2997,7 +3070,14 @@ static void damon_sysfs_producer_release(struct kobject *kobj)
 	kfree(producer);
 }
 
+static struct kobj_attribute damon_sysfs_producer_report_type_attr =
+		__ATTR_RW_MODE(report_type, 0600);
+static struct kobj_attribute damon_sysfs_producer_producer_state_type_attr =
+		__ATTR_RW_MODE(producer_state, 0600);
+
 static struct attribute *damon_sysfs_producer_attrs[] = {
+	&damon_sysfs_producer_report_type_attr.attr,
+	&damon_sysfs_producer_producer_state_type_attr.attr,
 	NULL,
 };
 ATTRIBUTE_GROUPS(damon_sysfs_producer);
-- 
2.47.3