[PATCH v2 3/4] samples/damon: fix damon sample mtier for start failure

[Honggyu Kim <honggyu.kim@sk.com>]

The damon_sample_mtier_start() can fail so we must reset the "enable"
parameter to "false" again for proper rollback.

In such cases, setting Y to "enable" then N triggers the similar crash
with mtier because damon sample start failed but the "enable" stays as Y.

Fixes: 82a08bde3cf7 ("samples/damon: implement a DAMON module for memory tiering")
Signed-off-by: Honggyu Kim <honggyu.kim@sk.com>
Reviewed-by: SeongJae Park <sj@kernel.org>
---
 samples/damon/mtier.c | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/samples/damon/mtier.c b/samples/damon/mtier.c
index 36d2cd933f5a..c94254b77fc9 100644
--- a/samples/damon/mtier.c
+++ b/samples/damon/mtier.c
@@ -164,8 +164,12 @@ static int damon_sample_mtier_enable_store(
 	if (enable == enabled)
 		return 0;
 
-	if (enable)
-		return damon_sample_mtier_start();
+	if (enable) {
+		err = damon_sample_mtier_start();
+		if (err)
+			enable = false;
+		return err;
+	}
 	damon_sample_mtier_stop();
 	return 0;
 }
-- 
2.34.1