From 6472f6d2f7d90c0e8b32bd13acd45622635b04cc Mon Sep 17 00:00:00 2001 From: Muchun Song Date: Thu, 28 Apr 2022 23:16:10 -0700 Subject: [PATCH] mm: pvmw: add support for walking devmap pages The devmap pages can not use page_vma_mapped_walk() to check if a huge devmap page is mapped into a vma. Add support for walking huge devmap pages so that DAX can use it in the next patch. Link: https://lkml.kernel.org/r/20220403053957.10770-5-songmuchun@bytedance.com Signed-off-by: Muchun Song Cc: Alistair Popple Cc: Al Viro Cc: Christoph Hellwig Cc: Dan Williams Cc: Hugh Dickins Cc: Jan Kara Cc: "Kirill A. Shutemov" Cc: Matthew Wilcox Cc: Ralph Campbell Cc: Ross Zwisler Cc: Xiongchun Duan Cc: Xiyu Yang Cc: Yang Shi Signed-off-by: Andrew Morton --- mm/page_vma_mapped.c | 17 +++++++++-------- 1 file changed, 9 insertions(+), 8 deletions(-) diff --git a/mm/page_vma_mapped.c b/mm/page_vma_mapped.c index 14a5cda73dee..c10f839fc410 100644 --- a/mm/page_vma_mapped.c +++ b/mm/page_vma_mapped.c @@ -210,16 +210,10 @@ bool page_vma_mapped_walk(struct page_vma_mapped_walk *pvmw) */ pmde = READ_ONCE(*pvmw->pmd); - if (pmd_trans_huge(pmde) || is_pmd_migration_entry(pmde)) { + if (pmd_trans_huge(pmde) || is_pmd_migration_entry(pmde) || + (pmd_present(pmde) && pmd_devmap(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 (!check_pmd(pmd_pfn(pmde), pvmw)) - return not_found(pvmw); - return true; - } if (!pmd_present(pmde)) { swp_entry_t entry; @@ -232,6 +226,13 @@ bool page_vma_mapped_walk(struct page_vma_mapped_walk *pvmw) return not_found(pvmw); return true; } + if (likely(pmd_trans_huge(pmde) || pmd_devmap(pmde))) { + if (pvmw->flags & PVMW_MIGRATION) + return not_found(pvmw); + if (!check_pmd(pmd_pfn(pmde), pvmw)) + return not_found(pvmw); + return true; + } /* THP pmd was split under us: handle on pte level */ spin_unlock(pvmw->ptl); pvmw->ptl = NULL;