Implement sysfs files under the data probe filter directory for letting
users to configure each filter.

Signed-off-by: SeongJae Park <sj@kernel.org>
---
 mm/damon/sysfs.c | 114 +++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 114 insertions(+)

diff --git a/mm/damon/sysfs.c b/mm/damon/sysfs.c
index 25487a0268cbe..ed7bb734a236b 100644
--- a/mm/damon/sysfs.c
+++ b/mm/damon/sysfs.c
@@ -753,6 +753,9 @@ static const struct kobj_type damon_sysfs_intervals_ktype = {
 
 struct damon_sysfs_filter {
 	struct kobject kobj;
+	enum damon_filter_type type;
+	bool matching;
+	bool allow;
 };
 
 static struct damon_sysfs_filter *damon_sysfs_filter_alloc(void)
@@ -760,6 +763,105 @@ static struct damon_sysfs_filter *damon_sysfs_filter_alloc(void)
 	return kzalloc_obj(struct damon_sysfs_filter);
 }
 
+struct damon_sysfs_filter_type_name {
+	enum damon_filter_type type;
+	char *name;
+};
+
+static const struct damon_sysfs_filter_type_name
+damon_sysfs_filter_type_names[] = {
+	{
+		.type = DAMON_FILTER_TYPE_ANON,
+		.name = "anon",
+	},
+};
+
+static ssize_t type_show(struct kobject *kobj,
+		struct kobj_attribute *attr, char *buf)
+{
+	struct damon_sysfs_filter *filter = container_of(kobj,
+			struct damon_sysfs_filter, kobj);
+	int i;
+
+	for (i = 0; i < ARRAY_SIZE(damon_sysfs_filter_type_names); i++) {
+		const struct damon_sysfs_filter_type_name *type_name;
+
+		type_name = &damon_sysfs_filter_type_names[i];
+		if (type_name->type == filter->type)
+			return sysfs_emit(buf, "%s\n", type_name->name);
+	}
+	return -EINVAL;
+}
+
+static ssize_t type_store(struct kobject *kobj,
+		struct kobj_attribute *attr, const char *buf, size_t count)
+{
+	struct damon_sysfs_filter *filter = container_of(kobj,
+			struct damon_sysfs_filter, kobj);
+	ssize_t ret = -EINVAL;
+	int i;
+
+	for (i = 0; i < ARRAY_SIZE(damon_sysfs_filter_type_names); i++) {
+		const struct damon_sysfs_filter_type_name *type_name;
+
+		type_name = &damon_sysfs_filter_type_names[i];
+		if (sysfs_streq(buf, type_name->name)) {
+			filter->type = type_name->type;
+			ret = count;
+			break;
+		}
+	}
+	return ret;
+}
+
+static ssize_t matching_show(struct kobject *kobj,
+		struct kobj_attribute *attr, char *buf)
+{
+	struct damon_sysfs_filter *filter = container_of(kobj,
+			struct damon_sysfs_filter, kobj);
+
+	return sysfs_emit(buf, "%c\n", filter->matching ? 'Y' : 'N');
+}
+
+static ssize_t matching_store(struct kobject *kobj,
+		struct kobj_attribute *attr, const char *buf, size_t count)
+{
+	struct damon_sysfs_filter *filter = container_of(kobj,
+			struct damon_sysfs_filter, kobj);
+	bool matching;
+	int err = kstrtobool(buf, &matching);
+
+	if (err)
+		return err;
+
+	filter->matching = matching;
+	return count;
+}
+
+static ssize_t allow_show(struct kobject *kobj,
+		struct kobj_attribute *attr, char *buf)
+{
+	struct damon_sysfs_filter *filter = container_of(kobj,
+			struct damon_sysfs_filter, kobj);
+
+	return sysfs_emit(buf, "%c\n", filter->allow ? 'Y' : 'N');
+}
+
+static ssize_t allow_store(struct kobject *kobj,
+		struct kobj_attribute *attr, const char *buf, size_t count)
+{
+	struct damon_sysfs_filter *filter = container_of(kobj,
+			struct damon_sysfs_filter, kobj);
+	bool allow;
+	int err = kstrtobool(buf, &allow);
+
+	if (err)
+		return err;
+
+	filter->allow = allow;
+	return count;
+}
+
 static void damon_sysfs_filter_release(struct kobject *kobj)
 {
 	struct damon_sysfs_filter *filter = container_of(kobj,
@@ -768,7 +870,19 @@ static void damon_sysfs_filter_release(struct kobject *kobj)
 	kfree(filter);
 }
 
+static struct kobj_attribute damon_sysfs_filter_type_attr =
+		__ATTR_RW_MODE(type, 0600);
+
+static struct kobj_attribute damon_sysfs_filter_matching_attr =
+		__ATTR_RW_MODE(matching, 0600);
+
+static struct kobj_attribute damon_sysfs_filter_allow_attr =
+		__ATTR_RW_MODE(allow, 0600);
+
 static struct attribute *damon_sysfs_filter_attrs[] = {
+	&damon_sysfs_filter_type_attr.attr,
+	&damon_sysfs_filter_matching_attr.attr,
+	&damon_sysfs_filter_allow_attr.attr,
 	NULL,
 };
 ATTRIBUTE_GROUPS(damon_sysfs_filter);
-- 
2.47.3