mm: mempolicy: skip inaccessible VMAs when setting MPOL_MF_LAZY

PROT_NUMA VMAs are skipped to avoid problems distinguishing between
present, prot_none and special entries.  MPOL_MF_LAZY is not visible from
userspace since commit a720094d ("mm: mempolicy: Hide MPOL_NOOP and
MPOL_MF_LAZY from userspace for now") but it should still skip VMAs the
same way task_numa_work does.
Signed-off-by: NMel Gorman <mgorman@suse.de>
Acked-by: NRik van Riel <riel@redhat.com>
Acked-by: NHugh Dickins <hughd@google.com>
Acked-by: NPeter Zijlstra <peterz@infradead.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

mm/mempolicy.c

@@ -681,6 +681,8 @@ queue_pages_range(struct mm_struct *mm, unsigned long start, unsigned long end,
 		}
 
 		if (flags & MPOL_MF_LAZY) {
+			/* Similar to task_numa_work, skip inaccessible VMAs */
+			if (vma->vm_flags & (VM_READ | VM_EXEC | VM_WRITE))
 				change_prot_numa(vma, start, endvma);
 			goto next;
 		}