mm: cleanup *pte_alloc* interfaces

There are few things about *pte_alloc*() helpers worth cleaning up:

 - 'vma' argument is unused, let's drop it;

 - most __pte_alloc() callers do speculative check for pmd_none(),
   before taking ptl: let's introduce pte_alloc() macro which does
   the check.

   The only direct user of __pte_alloc left is userfaultfd, which has
   different expectation about atomicity wrt pmd.

 - pte_alloc_map() and pte_alloc_map_lock() are redefined using
   pte_alloc().

[sudeep.holla@arm.com: fix build for arm64 hugetlbpage]
[sfr@canb.auug.org.au: fix arch/arm/mm/mmu.c some more]
Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Dave Hansen <dave.hansen@intel.com>
Signed-off-by: Sudeep Holla <sudeep.holla@arm.com>
Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 1 insertions, 2 deletions

diff --git a/mm/mremap.c b/mm/mremap.c
index e30c8a6489a6..3fa0a467df66 100644
--- a/mm/mremap.c
+++ b/mm/mremap.c
@@ -213,8 +213,7 @@ unsigned long move_page_tables(struct vm_area_struct *vma,
                                 continue;
                         VM_BUG_ON(pmd_trans_huge(*old_pmd));
                 }
-                if (pmd_none(*new_pmd) && __pte_alloc(new_vma->vm_mm, new_vma,
-                                                      new_pmd, new_addr))
+                if (pte_alloc(new_vma->vm_mm, new_pmd, new_addr))
                         break;
                 next = (new_addr + PMD_SIZE) & PMD_MASK;
                 if (extent > next - new_addr)