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, 3 insertions, 5 deletions

diff --git a/mm/memory.c b/mm/memory.c
index 0e247642ed5b..1974fc02c4d0 100644
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -562,8 +562,7 @@ void free_pgtables(struct mmu_gather *tlb, struct vm_area_struct *vma,
         }
 }
 
-int __pte_alloc(struct mm_struct *mm, struct vm_area_struct *vma,
-                pmd_t *pmd, unsigned long address)
+int __pte_alloc(struct mm_struct *mm, pmd_t *pmd, unsigned long address)
 {
         spinlock_t *ptl;
         pgtable_t new = pte_alloc_one(mm, address);
@@ -3419,12 +3418,11 @@ static int __handle_mm_fault(struct mm_struct *mm, struct vm_area_struct *vma,
         }
 
         /*
-         * Use __pte_alloc instead of pte_alloc_map, because we can't
+         * Use pte_alloc() instead of pte_alloc_map, because we can't
          * run pte_offset_map on the pmd, if an huge pmd could
          * materialize from under us from a different thread.
          */
-        if (unlikely(pmd_none(*pmd)) &&
-            unlikely(__pte_alloc(mm, vma, pmd, address)))
+        if (unlikely(pte_alloc(mm, pmd, address)))
                 return VM_FAULT_OOM;
         /*
          * If a huge pmd materialized under us just retry later.  Use