1 files changed, 66 insertions, 0 deletions
diff --git a/mm/damon/core.c b/mm/damon/core.c
index be93fb1c3473..82e0a4620c4f 100644
--- a/mm/damon/core.c
+++ b/mm/damon/core.c
@@ -25,6 +25,72 @@
 static DEFINE_MUTEX(damon_lock);
 static int nr_running_ctxs;
 
+static DEFINE_MUTEX(damon_ops_lock);
+static struct damon_operations damon_registered_ops[NR_DAMON_OPS];
+
+/* Should be called under damon_ops_lock with id smaller than NR_DAMON_OPS */
+static bool damon_registered_ops_id(enum damon_ops_id id)
+{
+	struct damon_operations empty_ops = {};
+
+	if (!memcmp(&empty_ops, &damon_registered_ops[id], sizeof(empty_ops)))
+		return false;
+	return true;
+}
+
+/**
+ * damon_register_ops() - Register a monitoring operations set to DAMON.
+ * @ops:	monitoring operations set to register.
+ *
+ * This function registers a monitoring operations set of valid &struct
+ * damon_operations->id so that others can find and use them later.
+ *
+ * Return: 0 on success, negative error code otherwise.
+ */
+int damon_register_ops(struct damon_operations *ops)
+{
+	int err = 0;
+
+	if (ops->id >= NR_DAMON_OPS)
+		return -EINVAL;
+	mutex_lock(&damon_ops_lock);
+	/* Fail for already registered ops */
+	if (damon_registered_ops_id(ops->id)) {
+		err = -EINVAL;
+		goto out;
+	}
+	damon_registered_ops[ops->id] = *ops;
+out:
+	mutex_unlock(&damon_ops_lock);
+	return err;
+}
+
+/**
+ * damon_select_ops() - Select a monitoring operations to use with the context.
+ * @ctx:	monitoring context to use the operations.
+ * @id:		id of the registered monitoring operations to select.
+ *
+ * This function finds registered monitoring operations set of @id and make
+ * @ctx to use it.
+ *
+ * Return: 0 on success, negative error code otherwise.
+ */
+int damon_select_ops(struct damon_ctx *ctx, enum damon_ops_id id)
+{
+	int err = 0;
+
+	if (id >= NR_DAMON_OPS)
+		return -EINVAL;
+
+	mutex_lock(&damon_ops_lock);
+	if (!damon_registered_ops_id(id))
+		err = -EINVAL;
+	else
+		ctx->ops = damon_registered_ops[id];
+	mutex_unlock(&damon_ops_lock);
+	return err;
+}
+
 /*
  * Construct a damon_region struct
  *