Merge v6.18.50linux-rolling-lts

Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

1 files changed, 8 insertions, 2 deletions

diff --git a/mm/gup.c b/mm/gup.c
index 95d948c8e86c..2264a36bc773 100644
--- a/mm/gup.c
+++ b/mm/gup.c
@@ -2273,6 +2273,7 @@ static unsigned long collect_longterm_unpinnable_folios(
 
 	for (folio = pofs_get_folio(pofs, i); folio;
 	     folio = pofs_next_folio(folio, pofs, &i)) {
+		const int pin_refs = folio_has_pincount(folio) ? 1 : GUP_PIN_COUNTING_BIAS;
 
 		if (folio_is_longterm_pinnable(folio))
 			continue;
@@ -2287,15 +2288,20 @@ static unsigned long collect_longterm_unpinnable_folios(
 			continue;
 		}
 
+		/*
+		 * We drain not only to make the folio_isolate_lru() succeed,
+		 * but also to remove any other folio references from LRU
+		 * caches.
+		 */
 		if (drained == 0 && folio_may_be_lru_cached(folio) &&
 				folio_ref_count(folio) !=
-				folio_expected_ref_count(folio) + 1) {
+				folio_expected_ref_count(folio) + pin_refs) {
 			lru_add_drain();
 			drained = 1;
 		}
 		if (drained == 1 && folio_may_be_lru_cached(folio) &&
 				folio_ref_count(folio) !=
-				folio_expected_ref_count(folio) + 1) {
+				folio_expected_ref_count(folio) + pin_refs) {
 			lru_add_drain_all();
 			drained = 2;
 		}