damon_sample_mtier is assuming DAMON is ready to use in module_init
time, and uses its own hack to see if it is the time.  Use
damon_initialized(), which is a way for seeing if DAMON is ready to be
used that is more reliable and better to maintain instead of the hack.

Signed-off-by: SeongJae Park <sj@kernel.org>
---
 samples/damon/mtier.c | 11 +++++++----
 1 file changed, 7 insertions(+), 4 deletions(-)

diff --git a/samples/damon/mtier.c b/samples/damon/mtier.c
index beaf36657dea..775838a23d93 100644
--- a/samples/damon/mtier.c
+++ b/samples/damon/mtier.c
@@ -193,8 +193,6 @@ static void damon_sample_mtier_stop(void)
 	damon_destroy_ctx(ctxs[1]);
 }
 
-static bool init_called;
-
 static int damon_sample_mtier_enable_store(
 		const char *val, const struct kernel_param *kp)
 {
@@ -208,7 +206,7 @@ static int damon_sample_mtier_enable_store(
 	if (enabled == is_enabled)
 		return 0;
 
-	if (!init_called)
+	if (!damon_initialized())
 		return 0;
 
 	if (enabled) {
@@ -225,7 +223,12 @@ static int __init damon_sample_mtier_init(void)
 {
 	int err = 0;
 
-	init_called = true;
+	if (!damon_initialized()) {
+		if (enabled)
+			enabled = false;
+		return -ENOMEM;
+	}
+
 	if (enabled) {
 		err = damon_sample_mtier_start();
 		if (err)
-- 
2.39.5