[PATCH 5.12 093/110] mm: page_vma_mapped_walk(): prettify PVMW_MIGRATION block

From: Sasha Levin
Date: Mon Jun 28 2021 - 10:26:30 EST


From: Hugh Dickins <hughd@xxxxxxxxxx>

commit e2e1d4076c77b3671cf8ce702535ae7dee3acf89 upstream.

page_vma_mapped_walk() cleanup: rearrange the !pmd_present() block to
follow the same "return not_found, return not_found, return true"
pattern as the block above it (note: returning not_found there is never
premature, since existence or prior existence of huge pmd guarantees
good alignment).

Link: https://lkml.kernel.org/r/378c8650-1488-2edf-9647-32a53cf2e21@xxxxxxxxxx
Signed-off-by: Hugh Dickins <hughd@xxxxxxxxxx>
Acked-by: Kirill A. Shutemov <kirill.shutemov@xxxxxxxxxxxxxxx>
Reviewed-by: Peter Xu <peterx@xxxxxxxxxx>
Cc: Alistair Popple <apopple@xxxxxxxxxx>
Cc: Matthew Wilcox <willy@xxxxxxxxxxxxx>
Cc: Ralph Campbell <rcampbell@xxxxxxxxxx>
Cc: Wang Yugui <wangyugui@xxxxxxxxxxxx>
Cc: Will Deacon <will@xxxxxxxxxx>
Cc: Yang Shi <shy828301@xxxxxxxxx>
Cc: Zi Yan <ziy@xxxxxxxxxx>
Cc: <stable@xxxxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
mm/page_vma_mapped.c | 30 ++++++++++++++----------------
1 file changed, 14 insertions(+), 16 deletions(-)

diff --git a/mm/page_vma_mapped.c b/mm/page_vma_mapped.c
index 825c97a479e6..96cef824f52f 100644
--- a/mm/page_vma_mapped.c
+++ b/mm/page_vma_mapped.c
@@ -198,24 +198,22 @@ restart:
if (pmd_page(pmde) != page)
return not_found(pvmw);
return true;
- } else if (!pmd_present(pmde)) {
- if (thp_migration_supported()) {
- if (!(pvmw->flags & PVMW_MIGRATION))
- return not_found(pvmw);
- if (is_migration_entry(pmd_to_swp_entry(pmde))) {
- swp_entry_t entry = pmd_to_swp_entry(pmde);
+ }
+ if (!pmd_present(pmde)) {
+ swp_entry_t entry;

- if (migration_entry_to_page(entry) != page)
- return not_found(pvmw);
- return true;
- }
- }
- return not_found(pvmw);
- } else {
- /* THP pmd was split under us: handle on pte level */
- spin_unlock(pvmw->ptl);
- pvmw->ptl = NULL;
+ if (!thp_migration_supported() ||
+ !(pvmw->flags & PVMW_MIGRATION))
+ return not_found(pvmw);
+ entry = pmd_to_swp_entry(pmde);
+ if (!is_migration_entry(entry) ||
+ migration_entry_to_page(entry) != page)
+ return not_found(pvmw);
+ return true;
}
+ /* THP pmd was split under us: handle on pte level */
+ spin_unlock(pvmw->ptl);
+ pvmw->ptl = NULL;
} else if (!pmd_present(pmde)) {
/*
* If PVMW_SYNC, take and drop THP pmd lock so that we
--
2.30.2