[PATCH] mm/damon/ops-common: factor out damon_putback_folio_list()

From: Li Youhong <[email protected]>

The putback loop is duplicated in damon_migrate_folio_list() and on the
invalid-nid path of damon_migrate_pages().  Factor it into a small helper
for readability.  No functional change.

Signed-off-by: Li Youhong <[email protected]>

---
Note:
As previously pointed out by the AI regarding whether removing the local
variable struct folio *folio in the damon_migrate_folio_list()function
would introduce build-time issues: no build failure will actually occur.
This is because struct folio *folio is only used inside the while-loop.
link: https://lore.kernel.org/all/[email protected]/

---
 mm/damon/ops-common.c | 31 +++++++++++++++----------------
 1 file changed, 15 insertions(+), 16 deletions(-)

diff --git a/mm/damon/ops-common.c b/mm/damon/ops-common.c
index 0bcad6b1e5b9..5c0c941b7f75 100644
--- a/mm/damon/ops-common.c
+++ b/mm/damon/ops-common.c
@@ -329,12 +329,24 @@ static unsigned int __damon_migrate_folio_list(
 	return nr_succeeded;
 }
 
+static void damon_putback_folio_list(struct list_head *folio_list)
+{
+	struct folio *folio;
+
+	while (!list_empty(folio_list)) {
+		folio = lru_to_folio(folio_list);
+		list_del(&folio->lru);
+		node_stat_sub_folio(folio, NR_ISOLATED_ANON +
+				folio_is_file_lru(folio));
+		folio_putback_lru(folio);
+	}
+}
+
 static unsigned int damon_migrate_folio_list(struct list_head *folio_list,
 						struct pglist_data *pgdat,
 						int target_nid)
 {
 	unsigned int nr_migrated = 0;
-	struct folio *folio;
 	LIST_HEAD(ret_folios);
 	LIST_HEAD(migrate_folios);
 
@@ -372,13 +384,7 @@ static unsigned int damon_migrate_folio_list(struct list_head *folio_list,
 
 	list_splice(&ret_folios, folio_list);
 
-	while (!list_empty(folio_list)) {
-		folio = lru_to_folio(folio_list);
-		list_del(&folio->lru);
-		node_stat_sub_folio(folio, NR_ISOLATED_ANON +
-				folio_is_file_lru(folio));
-		folio_putback_lru(folio);
-	}
+	damon_putback_folio_list(folio_list);
 
 	return nr_migrated;
 }
@@ -395,14 +401,7 @@ unsigned long damon_migrate_pages(struct list_head *folio_list, int target_nid)
 
 	if (target_nid < 0 || target_nid >= MAX_NUMNODES ||
 			!node_state(target_nid, N_MEMORY)) {
-		while (!list_empty(folio_list)) {
-			struct folio *folio = lru_to_folio(folio_list);
-
-			list_del(&folio->lru);
-			node_stat_sub_folio(folio, NR_ISOLATED_ANON +
-					folio_is_file_lru(folio));
-			folio_putback_lru(folio);
-		}
+		damon_putback_folio_list(folio_list);
 		return nr_migrated;
 	}
 
-- 
2.25.1