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    Subject[PATCH 5.10 087/101] mm: page_vma_mapped_walk(): add a level of indentation
    Date
    From: Hugh Dickins <hughd@google.com>

    commit b3807a91aca7d21c05d5790612e49969117a72b9 upstream.

    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.

    [hughd@google.com: : page_vma_mapped_walk(): add a level of indentation fix]
    Link: https://lkml.kernel.org/r/7f817555-3ce1-c785-e438-87d8efdcaf26@google.com

    Link: https://lkml.kernel.org/r/efde211-f3e2-fe54-977-ef481419e7f3@google.com
    Signed-off-by: Hugh Dickins <hughd@google.com>
    Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
    Cc: Alistair Popple <apopple@nvidia.com>
    Cc: Matthew Wilcox <willy@infradead.org>
    Cc: Peter Xu <peterx@redhat.com>
    Cc: Ralph Campbell <rcampbell@nvidia.com>
    Cc: Wang Yugui <wangyugui@e16-tech.com>
    Cc: Will Deacon <will@kernel.org>
    Cc: Yang Shi <shy828301@gmail.com>
    Cc: Zi Yan <ziy@nvidia.com>
    Cc: <stable@vger.kernel.org>
    Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
    Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
    Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
    ---
    mm/page_vma_mapped.c | 105 ++++++++++++++++++++++---------------------
    1 file changed, 55 insertions(+), 50 deletions(-)

    diff --git a/mm/page_vma_mapped.c b/mm/page_vma_mapped.c
    index 36b40fd23f94..3c3a7cb2de85 100644
    --- a/mm/page_vma_mapped.c
    +++ b/mm/page_vma_mapped.c
    @@ -172,62 +172,67 @@ 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 = READ_ONCE(*pvmw->pmd);
    - 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 = READ_ONCE(*pvmw->pmd);

    - spin_unlock(ptl);
    + 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;
    +
    + 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;

    --
    2.30.2
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