From: Wenjie Qi Fault-around can map ready dropbehind folios without going through the normal page-cache lookup that clears dropbehind. A mapping represents a competing cached user, so retain the folio instead of forcibly unmapping it when writeback completes. Unmapped dropbehind folios continue through the existing invalidation path. Signed-off-by: Wenjie Qi --- Changes since v1: - Retain mapped folios instead of adding a stricter context predicate. - Remove the private helper and RCU include. mm/filemap.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/mm/filemap.c b/mm/filemap.c index 6afec636881f..00fd89cf6f55 100644 --- a/mm/filemap.c +++ b/mm/filemap.c @@ -1616,7 +1616,7 @@ static void filemap_end_dropbehind(struct folio *folio) return; if (!folio_test_clear_dropbehind(folio)) return; - if (mapping) + if (mapping && !folio_mapped(folio)) folio_unmap_invalidate(mapping, folio, 0); } -- 2.43.0