mm: always initialise folio->_deferred_list

Patch series "Various significant MM patches".

These patches all interact in annoying ways which make it tricky to send
them out in any way other than a big batch, even though there's not really
an overarching theme to connect them.

The big effects of this patch series are:

 - folio_test_hugetlb() becomes reliable, even when called without a
   page reference
 - We free up PG_slab, and we could always use more page flags
 - We no longer need to check PageSlab before calling page_mapcount()


This patch (of 9):

For compound pages which are at least order-2 (and hence have a
deferred_list), initialise it and then we can check at free that the page
is not part of a deferred list.  We recently found this useful to rule out
a source of corruption.

[[email protected]: always initialise folio->_deferred_list]
  Link: https://lkml.kernel.org/r/[email protected]
Link: https://lkml.kernel.org/r/[email protected]
Link: https://lkml.kernel.org/r/[email protected]
Signed-off-by: Matthew Wilcox (Oracle) <[email protected]>
Signed-off-by: Peter Xu <[email protected]>
Reviewed-by: David Hildenbrand <[email protected]>
Acked-by: Vlastimil Babka <[email protected]>
Cc: Miaohe Lin <[email protected]>
Cc: Muchun Song <[email protected]>
Cc: Oscar Salvador <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>

0 files changed, 0 insertions, 0 deletions