+ shmem-mapping_set_exiting-to-help-mapped-resilience.patch added to -mm tree

[Andrew Morton <akpm@linux-foundation.org>]

The patch titled
     Subject: shmem: mapping_set_exiting() to help mapped resilience
has been added to the -mm tree.  Its filename is
     shmem-mapping_set_exiting-to-help-mapped-resilience.patch

This patch should soon appear at
    https://ozlabs.org/~akpm/mmots/broken-out/shmem-mapping_set_exiting-to-help-mapped-resilience.patch
and later at
    https://ozlabs.org/~akpm/mmotm/broken-out/shmem-mapping_set_exiting-to-help-mapped-resilience.patch

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------------------------------------------------------
From: Hugh Dickins <hughd@google.com>
Subject: shmem: mapping_set_exiting() to help mapped resilience

When I added page_mapped() resilience in __delete_from_page_cache() for
the mapping_exiting() case, I missed that mapping_set_exiting() is done in
truncate_inode_pages_final(), which is not actually called for shmem. 
(Today, it is folio_mapped() resilience in filemap_unaccount_folio().)

So the fixup to avoid a memory leak in this case never worked on shmem:
add a mapping_set_exiting() in shmem_evict_inode() at last.  But this is
hardly a candidate for stable, since it's only useful if "Bad page".

Link: https://lkml.kernel.org/r/beefffda-6326-e36d-2d41-ed15b51af872@google.com
Fixes: 06b241f32c71 ("mm: __delete_from_page_cache show Bad page if mapped")
Signed-off-by: Hugh Dickins <hughd@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

 mm/shmem.c |    1 +
 1 file changed, 1 insertion(+)

--- a/mm/shmem.c~shmem-mapping_set_exiting-to-help-mapped-resilience
+++ a/mm/shmem.c
@@ -1129,6 +1129,7 @@ static void shmem_evict_inode(struct ino
 	if (shmem_mapping(inode->i_mapping)) {
 		shmem_unacct_size(info->flags, inode->i_size);
 		inode->i_size = 0;
+		mapping_set_exiting(inode->i_mapping);
 		shmem_truncate_range(inode, 0, (loff_t)-1);
 		if (!list_empty(&info->shrinklist)) {
 			spin_lock(&sbinfo->shrinklist_lock);
_

Patches currently in -mm which might be from hughd@google.com are

mm-fs-delete-pf_swapwrite.patch
mm-delete-__clearpagewaiters.patch
tmpfs-support-for-file-creation-time-fix.patch
shmem-mapping_set_exiting-to-help-mapped-resilience.patch
mm-_install_special_mapping-apply-vm_locked_clear_mask.patch
mm-thp-refix-__split_huge_pmd_locked-for-migration-pmd.patch
mm-thp-clearpagedoublemap-in-first-page_add_file_rmap.patch
mm-thp-fix-nr_file_mapped-accounting-in-page__file_rmap.patch