mm/memory.c: remove reduntant check for write access

Flags argument has been copied into vmf.flags and it is not changed in
between.  Hence a single write access check can be used for both PUD and
PMD.

Link: http://lkml.kernel.org/r/20170823082839.1812-1-khandual@linux.vnet.ibm.com
Signed-off-by: Anshuman Khandual <khandual@linux.vnet.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

diff --git a/mm/memory.c b/mm/memory.c
index ad0ea1a..7c521a6 100644 (file)
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -3961,6 +3961,7 @@ static int __handle_mm_fault(struct vm_area_struct *vma, unsigned long address,
                .pgoff = linear_page_index(vma, address),
                .gfp_mask = __get_fault_gfp_mask(vma),
        };
+       unsigned int dirty = flags & FAULT_FLAG_WRITE;
        struct mm_struct *mm = vma->vm_mm;
        pgd_t *pgd;
        p4d_t *p4d;
@@ -3983,7 +3984,6 @@ static int __handle_mm_fault(struct vm_area_struct *vma, unsigned long address,
 
                barrier();
                if (pud_trans_huge(orig_pud) || pud_devmap(orig_pud)) {
-                       unsigned int dirty = flags & FAULT_FLAG_WRITE;
 
                        /* NUMA case for anonymous PUDs would go here */
 
@@ -4020,8 +4020,7 @@ static int __handle_mm_fault(struct vm_area_struct *vma, unsigned long address,
                        if (pmd_protnone(orig_pmd) && vma_is_accessible(vma))
                                return do_huge_pmd_numa_page(&vmf, orig_pmd);
 
-                       if ((vmf.flags & FAULT_FLAG_WRITE) &&
-                                       !pmd_write(orig_pmd)) {
+                       if (dirty && !pmd_write(orig_pmd)) {
                                ret = wp_huge_pmd(&vmf, orig_pmd);
                                if (!(ret & VM_FAULT_FALLBACK))
                                        return ret;