From c7da82b894e9eef60a04a15f065a8502341bf13b Mon Sep 17 00:00:00 2001 From: Dan Williams Date: Wed, 29 Nov 2017 16:10:18 -0800 Subject: mm: replace pmd_write with pmd_access_permitted in fault + gup paths MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit The 'access_permitted' helper is used in the gup-fast path and goes beyond the simple _PAGE_RW check to also: - validate that the mapping is writable from a protection keys standpoint - validate that the pte has _PAGE_USER set since all fault paths where pmd_write is must be referencing user-memory. Link: http://lkml.kernel.org/r/151043111049.2842.15241454964150083466.stgit@dwillia2-desk3.amr.corp.intel.com Signed-off-by: Dan Williams Cc: Dave Hansen Cc: Kirill A. Shutemov Cc: "Jérôme Glisse" Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- fs/dax.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) (limited to 'fs/dax.c') diff --git a/fs/dax.c b/fs/dax.c index 95981591977a..78b72c48374e 100644 --- a/fs/dax.c +++ b/fs/dax.c @@ -627,7 +627,8 @@ static void dax_mapping_entry_mkclean(struct address_space *mapping, if (pfn != pmd_pfn(*pmdp)) goto unlock_pmd; - if (!pmd_dirty(*pmdp) && !pmd_write(*pmdp)) + if (!pmd_dirty(*pmdp) + && !pmd_access_permitted(*pmdp, WRITE)) goto unlock_pmd; flush_cache_page(vma, address, pfn); -- cgit v1.2.3