+ mm-dont-look-at-xarray-value-entries-in-split_huge_pages_in_file.patch added to mm-unstable branch

+ mm-dont-look-at-xarray-value-entries-in-split_huge_pages_in_file.patch added to mm-unstable branch

[Andrew Morton]

The patch titled
     Subject: mm: don't look at xarray value entries in split_huge_pages_in_file
has been added to the -mm mm-unstable branch.  Its filename is
     mm-dont-look-at-xarray-value-entries-in-split_huge_pages_in_file.patch

This patch will shortly appear at
     https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/mm-dont-look-at-xarray-value-entries-in-split_huge_pages_in_file.patch

This patch will later appear in the mm-unstable branch at
    git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

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------------------------------------------------------
From: Christoph Hellwig <hch@lst.de>
Subject: mm: don't look at xarray value entries in split_huge_pages_in_file
Date: Tue, 7 Mar 2023 15:34:04 +0100

Patch series "return an ERR_PTR from __filemap_get_folio", v3.

__filemap_get_folio and its wrappers can return NULL for three different
conditions, which in some cases requires the caller to reverse engineer
the decision making.  This is fixed by returning an ERR_PTR instead of
NULL and thus transporting the reason for the failure.  But to make
that work we first need to ensure that no xa_value special case is
returned and thus return the FGP_ENTRY flag.  It turns out that flag
is barely used and can usually be deal with in a better way.


This patch (of 7):

split_huge_pages_in_file never wants to do anything with the special value
enties.  Switch to using filemap_get_folio to not even see them.

Link: https://lkml.kernel.org/r/20230307143410.28031-1-hch@lst.de
Link: https://lkml.kernel.org/r/20230307143410.28031-2-hch@lst.de
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Hugh Dickins <hughd@google.com>
Cc: Andreas Gruenbacher <agruenba@redhat.com>
Cc: Ryusuke Konishi <konishi.ryusuke@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

 mm/huge_memory.c |    5 ++---
 1 file changed, 2 insertions(+), 3 deletions(-)

--- a/mm/huge_memory.c~mm-dont-look-at-xarray-value-entries-in-split_huge_pages_in_file
+++ a/mm/huge_memory.c
@@ -3093,11 +3093,10 @@ static int split_huge_pages_in_file(cons
 	mapping = candidate->f_mapping;
 
 	for (index = off_start; index < off_end; index += nr_pages) {
-		struct folio *folio = __filemap_get_folio(mapping, index,
-						FGP_ENTRY, 0);
+		struct folio *folio = filemap_get_folio(mapping, index);
 
 		nr_pages = 1;
-		if (xa_is_value(folio) || !folio)
+		if (!folio)
 			continue;
 
 		if (!folio_test_large(folio))
_

Patches currently in -mm which might be from hch@lst.de are

ufs-dont-flush-page-immediately-for-dirsync-directories.patch
ocfs2-dont-use-write_one_page-in-ocfs2_duplicate_clusters_by_page.patch
mmjfs-move-write_one_page-folio_write_one-to-jfs.patch
mm-dont-look-at-xarray-value-entries-in-split_huge_pages_in_file.patch
mm-make-mapping_get_entry-available-outside-of-filemapc.patch
mm-use-filemap_get_entry-in-filemap_get_incore_folio.patch
shmem-remove-shmem_get_partial_folio.patch
shmem-open-code-the-page-cache-lookup-in-shmem_get_folio_gfp.patch
mm-remove-fgp_entry.patch
mm-return-an-err_ptr-from-__filemap_get_folio.patch