From: Hugh Dickins <hughd@xxxxxxxxxx> 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@xxxxxxxxxx: : page_vma_mapped_walk(): add a level of indentation fix] Link: https://lkml.kernel.org/r/7f817555-3ce1-c785-e438-87d8efdcaf26@xxxxxxxxxx Link: https://lkml.kernel.org/r/efde211-f3e2-fe54-977-ef481419e7f3@xxxxxxxxxx Signed-off-by: Hugh Dickins <hughd@xxxxxxxxxx> Acked-by: Kirill A. Shutemov <kirill.shutemov@xxxxxxxxxxxxxxx> Cc: Alistair Popple <apopple@xxxxxxxxxx> Cc: Matthew Wilcox <willy@xxxxxxxxxxxxx> Cc: Peter Xu <peterx@xxxxxxxxxx> 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 | 105 ++++++++++++++++++++++--------------------- 1 file changed, 55 insertions(+), 50 deletions(-) diff --git a/mm/page_vma_mapped.c b/mm/page_vma_mapped.c index aad116532140..4a8a069c5e87 100644 --- a/mm/page_vma_mapped.c +++ b/mm/page_vma_mapped.c @@ -173,62 +173,67 @@ 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
