mm: use vma_is_anonymous() in create_huge_pmd() and wp_huge_pmd()

Let's use helper rather than direct check of vma->vm_ops to distinguish
anonymous VMA.

Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Reviewed-by: Oleg Nesterov <oleg@redhat.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

mm/memory.c

@@ -3233,7 +3233,7 @@ out:
 static int create_huge_pmd(struct mm_struct *mm, struct vm_area_struct *vma,
 			unsigned long address, pmd_t *pmd, unsigned int flags)
 {
-	if (!vma->vm_ops)
+	if (vma_is_anonymous(vma))
 		return do_huge_pmd_anonymous_page(mm, vma, address, pmd, flags);
 	if (vma->vm_ops->pmd_fault)
 		return vma->vm_ops->pmd_fault(vma, address, pmd, flags);
@@ -3244,7 +3244,7 @@ static int wp_huge_pmd(struct mm_struct *mm, struct vm_area_struct *vma,
 			unsigned long address, pmd_t *pmd, pmd_t orig_pmd,
 			unsigned int flags)
 {
-	if (!vma->vm_ops)
+	if (vma_is_anonymous(vma))
 		return do_huge_pmd_wp_page(mm, vma, address, pmd, orig_pmd);
 	if (vma->vm_ops->pmd_fault)
 		return vma->vm_ops->pmd_fault(vma, address, pmd, flags);