On 17.05.23 04:21, Peter Collingbourne wrote:
We would like to move away from requiring architectures to restore
metadata from swap in the set_pte_at() implementation, as this is not only
error-prone but adds complexity to the arch-specific code. This requires
us to call arch_swap_restore() before calling swap_free() whenever pages
are restored from swap. We are currently doing so everywhere except in
unuse_pte(); do so there as well.
Signed-off-by: Peter Collingbourne <pcc@xxxxxxxxxx>
Link: https://linux-review.googlesource.com/id/I68276653e612d64cde271ce1b5a99ae05d6bbc4f
---
mm/swapfile.c | 7 +++++++
1 file changed, 7 insertions(+)
diff --git a/mm/swapfile.c b/mm/swapfile.c
index 274bbf797480..e9843fadecd6 100644
--- a/mm/swapfile.c
+++ b/mm/swapfile.c
@@ -1794,6 +1794,13 @@ static int unuse_pte(struct vm_area_struct *vma, pmd_t *pmd,
goto setpte;
}
+ /*
+ * Some architectures may have to restore extra metadata to the page
+ * when reading from swap. This metadata may be indexed by swap entry
+ * so this must be called before swap_free().
+ */
+ arch_swap_restore(entry, page_folio(page));
+
/* See do_swap_page() */
BUG_ON(!PageAnon(page) && PageMappedToDisk(page));
BUG_ON(PageAnon(page) && PageAnonExclusive(page));
Acked-by: David Hildenbrand <david@xxxxxxxxxx>
--
Thanks,
David / dhildenb
