DAMON_RECLAIM directly uses damon_ctx->kdamond field with manual
synchronization using damon_ctx->kdamond_lock, to get the pid of the
kdamond.  Use a new dedicated function for the purpose, namely
damon_kdamond_pid(), since that doesn't require manual and error-prone
synchronization.

Signed-off-by: SeongJae Park <sj@kernel.org>
---
 mm/damon/reclaim.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/mm/damon/reclaim.c b/mm/damon/reclaim.c
index 8463a5a5032f..55df43e241c5 100644
--- a/mm/damon/reclaim.c
+++ b/mm/damon/reclaim.c
@@ -307,7 +307,9 @@ static int damon_reclaim_turn(bool on)
 	err = damon_start(&ctx, 1, true);
 	if (err)
 		return err;
-	kdamond_pid = ctx->kdamond->pid;
+	kdamond_pid = damon_kdamond_pid(ctx);
+	if (kdamond_pid < 0)
+		return kdamond_pid;
 	return damon_call(ctx, &call_control);
 }
 
-- 
2.47.3