[PATCH 07/11] mm: page_vma_mapped_walk(): add a level of indentation

Hugh Dickins
2021-06-10T06:46:35Z

page_vma_mapped_walk() cleanup: add a level of indentation to much of
the body, making no functional change in this commit, but reducing the
later diff when this is all converted to a loop.

Signed-off-by: Hugh Dickins <hughd@google.com>
Cc: <stable@vger.kernel.org>
---
mm/page_vma_mapped.c | 109 +++++++++++++++++++++++----------------------
1 file changed, 56 insertions(+), 53 deletions(-)

diff --git a/mm/page_vma_mapped.c b/mm/page_vma_mapped.c
index 0fe6e558d336..0840079ef7d2 100644
--- a/mm/page_vma_mapped.c
+++ b/mm/page_vma_mapped.c
@@ -173,65 +173,68 @@ bool page_vma_mapped_walk(struct page_vma_mapped_walk *pvmw)
if (pvmw->pte)
goto next_pte;
restart:
- pgd = pgd_offset(mm, pvmw->address);
- if (!pgd_present(*pgd))
- return false;
- p4d = p4d_offset(pgd, pvmw->address);
- if (!p4d_present(*p4d))
- return false;
- pud = pud_offset(p4d, pvmw->address);
- if (!pud_present(*pud))
- return false;
-
- pvmw->pmd = pmd_offset(pud, pvmw->address);
- /*
- * Make sure the pmd value isn't cached in a register by the
- * compiler and used as a stale value after we've observed a
- * subsequent update.
- */
- pmde = pmd_read_atomic(pvmw->pmd);
- barrier();
-
- if (pmd_trans_huge(pmde) || is_pmd_migration_entry(pmde)) {
- pvmw->ptl = pmd_lock(mm, pvmw->pmd);
- pmde = *pvmw->pmd;
- if (likely(pmd_trans_huge(pmde))) {
- if (pvmw->flags & PVMW_MIGRATION)
- return not_found(pvmw);
- if (pmd_page(pmde) != page)
- return not_found(pvmw);
- return true;
- }
- if (!pmd_present(pmde)) {
- swp_entry_t entry;
+ {
+ pgd = pgd_offset(mm, pvmw->address);
+ if (!pgd_present(*pgd))
+ return false;
+ p4d = p4d_offset(pgd, pvmw->address);
+ if (!p4d_present(*p4d))
+ return false;
+ pud = pud_offset(p4d, pvmw->address);
+ if (!pud_present(*pud))
+ return false;

- 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)) {
+ pvmw->pmd = pmd_offset(pud, pvmw->address);
/*
- * If PVMW_SYNC, take and drop THP pmd lock so that we
- * cannot return prematurely, while zap_huge_pmd() has
- * cleared *pmd but not decremented compound_mapcount().
+ * Make sure the pmd value isn't cached in a register by the
+ * compiler and used as a stale value after we've observed a
+ * subsequent update.
*/
- if ((pvmw->flags & PVMW_SYNC) && PageTransCompound(page)) {
- spinlock_t *ptl = pmd_lock(mm, pvmw->pmd);
+ pmde = pmd_read_atomic(pvmw->pmd);
+ barrier();
+
+ if (pmd_trans_huge(pmde) || is_pmd_migration_entry(pmde)) {
+ pvmw->ptl = pmd_lock(mm, pvmw->pmd);
+ pmde = *pvmw->pmd;
+ if (likely(pmd_trans_huge(pmde))) {
+ if (pvmw->flags & PVMW_MIGRATION)
+ return not_found(pvmw);
+ if (pmd_page(pmde) != page)
+ return not_found(pvmw);
+ return true;
+ }
+ if (!pmd_present(pmde)) {
+ swp_entry_t entry;

- spin_unlock(ptl);
+ 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
+ * cannot return prematurely, while zap_huge_pmd() has
+ * cleared *pmd but not decremented compound_mapcount().
+ */
+ if ((pvmw->flags & PVMW_SYNC) &&
+ PageTransCompound(page)) {
+ spinlock_t *ptl = pmd_lock(mm, pvmw->pmd);
+
+ spin_unlock(ptl);
+ }
+ return false;
}
- return false;
+ if (!map_pte(pvmw))
+ goto next_pte;
}
- if (!map_pte(pvmw))
- goto next_pte;
while (1) {
unsigned long end;

--
2.26.2