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From:   Yuanzheng Song <songyuanzheng@huawei.com>
To:     <sj@kernel.org>, <akpm@linux-foundation.org>
CC:     <damon@lists.linux.dev>, <linux-mm@kvack.org>,
        <linux-kernel@vger.kernel.org>
Subject: [PATCH] mm/damon/reclaim: fix 'enabled' is incorrectly set because 'system_wq' is not initialized
Date:   Fri, 15 Jul 2022 06:16:09 +0000
Message-ID: <20220715061609.48463-1-songyuanzheng@huawei.com>
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The 'enabled' will be incorrectly set because the 'system_wq'
might not initialized yet. This results in 'enabled=true',
but the 'damon_reclaim_timer' is inactive. So fix it by moving
the judgment logic of the 'damon_reclaim_initialized' to the
start position of the enable_store().

Fixes: 294928293813 ("mm/damon/reclaim: schedule 'damon_reclaim_timer' only after 'system_wq' is initialized")
Signed-off-by: Yuanzheng Song <songyuanzheng@huawei.com>
---
 mm/damon/reclaim.c | 9 +++++----
 1 file changed, 5 insertions(+), 4 deletions(-)

diff --git a/mm/damon/reclaim.c b/mm/damon/reclaim.c
index e69b807fefe4..b13d5a02bf2e 100644
--- a/mm/damon/reclaim.c
+++ b/mm/damon/reclaim.c
@@ -374,13 +374,14 @@ static bool damon_reclaim_initialized;
 static int damon_reclaim_enabled_store(const char *val,
 		const struct kernel_param *kp)
 {
-	int rc = param_set_bool(val, kp);
-
-	if (rc < 0)
-		return rc;
+	int rc;
 
 	/* system_wq might not initialized yet */
 	if (!damon_reclaim_initialized)
+		return -EINVAL;
+
+	rc = param_set_bool(val, kp);
+	if (rc < 0)
 		return rc;
 
 	schedule_delayed_work(&damon_reclaim_timer, 0);
-- 
2.25.1