From: Hugh Dickins <hughd@google.com> stable inclusion from linux-4.19.197 commit b114408b1aa2b0957877632113009bdf5efc5da2 -------------------------------- [ Upstream commit a765c417d876cc635f628365ec9aa6f09470069a ] page_vma_mapped_walk() cleanup: get THP's vma_address_end() at the start, rather than later at next_pte. It's a little unnecessary overhead on the first call, but makes for a simpler loop in the following commit. Link: https://lkml.kernel.org/r/4542b34d-862f-7cb4-bb22-e0df6ce830a2@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: Sasha Levin <sashal@kernel.org> Signed-off-by: Yang Yingliang <yangyingliang@huawei.com> --- mm/page_vma_mapped.c | 13 +++++++++---- 1 file changed, 9 insertions(+), 4 deletions(-) diff --git a/mm/page_vma_mapped.c b/mm/page_vma_mapped.c index 470f19c917ad5..7239c38e99e25 100644 --- a/mm/page_vma_mapped.c +++ b/mm/page_vma_mapped.c @@ -167,6 +167,15 @@ bool page_vma_mapped_walk(struct page_vma_mapped_walk *pvmw) return true; } + /* + * Seek to next pte only makes sense for THP. + * But more important than that optimization, is to filter out + * any PageKsm page: whose page->index misleads vma_address() + * and vma_address_end() to disaster. + */ + end = PageTransCompound(page) ? + vma_address_end(page, pvmw->vma) : + pvmw->address + PAGE_SIZE; if (pvmw->pte) goto next_pte; restart: @@ -234,10 +243,6 @@ bool page_vma_mapped_walk(struct page_vma_mapped_walk *pvmw) if (check_pte(pvmw)) return true; next_pte: - /* Seek to next pte only makes sense for THP */ - if (!PageTransHuge(page)) - return not_found(pvmw); - end = vma_address_end(page, pvmw->vma); do { pvmw->address += PAGE_SIZE; if (pvmw->address >= end) -- 2.25.1