[PATCH v2 5/9] mm: filemap: use xa_get_order() to get the swap entry order

[Baolin Wang <baolin.wang@linux.alibaba.com>]

In the following patches, shmem will support the swap out of large folios,
which means the shmem mappings may contain large order swap entries, so
using xa_get_order() to get the folio order of the shmem swap entry to
update the '*start' correctly.

Signed-off-by: Baolin Wang <baolin.wang@linux.alibaba.com>
---
 mm/filemap.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/mm/filemap.c b/mm/filemap.c
index 876cc64aadd7..ecc785758aaf 100644
--- a/mm/filemap.c
+++ b/mm/filemap.c
@@ -2056,6 +2056,8 @@ unsigned find_get_entries(struct address_space *mapping, pgoff_t *start,
 		folio = fbatch->folios[idx];
 		if (!xa_is_value(folio))
 			nr = folio_nr_pages(folio);
+		else
+			nr = 1 << xa_get_order(&mapping->i_pages, indices[idx]);
 		*start = indices[idx] + nr;
 	}
 	return folio_batch_count(fbatch);
@@ -2120,6 +2122,8 @@ unsigned find_lock_entries(struct address_space *mapping, pgoff_t *start,
 		folio = fbatch->folios[idx];
 		if (!xa_is_value(folio))
 			nr = folio_nr_pages(folio);
+		else
+			nr = 1 << xa_get_order(&mapping->i_pages, indices[idx]);
 		*start = indices[idx] + nr;
 	}
 	return folio_batch_count(fbatch);
-- 
2.39.3