On 17/05/2023 03:21, 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 Reviewed-by: Steven Price <steven.price@xxxxxxx> > --- > 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));
