[PATCH -V2 -mm 3/4] mm, hugetlbfs: Rename address to haddr in hugetlb_cow()

["Huang, Ying" <ying.huang@intel.com>]

From: Huang Ying <ying.huang@intel.com>

To take better advantage of general huge page copying optimization,
the target subpage address will be passed to hugetlb_cow(), then
copy_user_huge_page().  So we will use both target subpage address and
huge page size aligned address in hugetlb_cow().  To distinguish
between them, "haddr" is used for huge page size aligned address to be
consistent with Transparent Huge Page naming convention.

Now, only huge page size aligned address is used in hugetlb_cow(), so
the "address" is renamed to "haddr" in hugetlb_cow() in this patch.
Next patch will use target subpage address in hugetlb_cow() too.

The patch is just code cleanup without any functionality changes.

Signed-off-by: "Huang, Ying" <ying.huang@intel.com>
Suggested-by: Mike Kravetz <mike.kravetz@oracle.com>
Suggested-by: Michal Hocko <mhocko@suse.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
Cc: Andi Kleen <andi.kleen@intel.com>
Cc: Jan Kara <jack@suse.cz>
Cc: Matthew Wilcox <mawilcox@microsoft.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Shaohua Li <shli@fb.com>
Cc: Christopher Lameter <cl@linux.com>
Cc: "Aneesh Kumar K.V" <aneesh.kumar@linux.vnet.ibm.com>
Cc: Punit Agrawal <punit.agrawal@arm.com>
Cc: Anshuman Khandual <khandual@linux.vnet.ibm.com>
---
 mm/hugetlb.c | 26 ++++++++++++--------------
 1 file changed, 12 insertions(+), 14 deletions(-)

diff --git a/mm/hugetlb.c b/mm/hugetlb.c
index 696befffe6f7..ad3bec2ed269 100644
--- a/mm/hugetlb.c
+++ b/mm/hugetlb.c
@@ -3500,7 +3500,7 @@ static void unmap_ref_private(struct mm_struct *mm, struct vm_area_struct *vma,
  * Keep the pte_same checks anyway to make transition from the mutex easier.
  */
 static int hugetlb_cow(struct mm_struct *mm, struct vm_area_struct *vma,
-		       unsigned long address, pte_t *ptep,
+		       unsigned long haddr, pte_t *ptep,
 		       struct page *pagecache_page, spinlock_t *ptl)
 {
 	pte_t pte;
@@ -3518,7 +3518,7 @@ static int hugetlb_cow(struct mm_struct *mm, struct vm_area_struct *vma,
 	 * and just make the page writable */
 	if (page_mapcount(old_page) == 1 && PageAnon(old_page)) {
 		page_move_anon_rmap(old_page, vma);
-		set_huge_ptep_writable(vma, address, ptep);
+		set_huge_ptep_writable(vma, haddr, ptep);
 		return 0;
 	}
 
@@ -3542,7 +3542,7 @@ static int hugetlb_cow(struct mm_struct *mm, struct vm_area_struct *vma,
 	 * be acquired again before returning to the caller, as expected.
 	 */
 	spin_unlock(ptl);
-	new_page = alloc_huge_page(vma, address, outside_reserve);
+	new_page = alloc_huge_page(vma, haddr, outside_reserve);
 
 	if (IS_ERR(new_page)) {
 		/*
@@ -3555,11 +3555,10 @@ static int hugetlb_cow(struct mm_struct *mm, struct vm_area_struct *vma,
 		if (outside_reserve) {
 			put_page(old_page);
 			BUG_ON(huge_pte_none(pte));
-			unmap_ref_private(mm, vma, old_page, address);
+			unmap_ref_private(mm, vma, old_page, haddr);
 			BUG_ON(huge_pte_none(pte));
 			spin_lock(ptl);
-			ptep = huge_pte_offset(mm, address & huge_page_mask(h),
-					       huge_page_size(h));
+			ptep = huge_pte_offset(mm, haddr, huge_page_size(h));
 			if (likely(ptep &&
 				   pte_same(huge_ptep_get(ptep), pte)))
 				goto retry_avoidcopy;
@@ -3584,12 +3583,12 @@ static int hugetlb_cow(struct mm_struct *mm, struct vm_area_struct *vma,
 		goto out_release_all;
 	}
 
-	copy_user_huge_page(new_page, old_page, address, vma,
+	copy_user_huge_page(new_page, old_page, haddr, vma,
 			    pages_per_huge_page(h));
 	__SetPageUptodate(new_page);
 	set_page_huge_active(new_page);
 
-	mmun_start = address & huge_page_mask(h);
+	mmun_start = haddr;
 	mmun_end = mmun_start + huge_page_size(h);
 	mmu_notifier_invalidate_range_start(mm, mmun_start, mmun_end);
 
@@ -3598,25 +3597,24 @@ static int hugetlb_cow(struct mm_struct *mm, struct vm_area_struct *vma,
 	 * before the page tables are altered
 	 */
 	spin_lock(ptl);
-	ptep = huge_pte_offset(mm, address & huge_page_mask(h),
-			       huge_page_size(h));
+	ptep = huge_pte_offset(mm, haddr, huge_page_size(h));
 	if (likely(ptep && pte_same(huge_ptep_get(ptep), pte))) {
 		ClearPagePrivate(new_page);
 
 		/* Break COW */
-		huge_ptep_clear_flush(vma, address, ptep);
+		huge_ptep_clear_flush(vma, haddr, ptep);
 		mmu_notifier_invalidate_range(mm, mmun_start, mmun_end);
-		set_huge_pte_at(mm, address, ptep,
+		set_huge_pte_at(mm, haddr, ptep,
 				make_huge_pte(vma, new_page, 1));
 		page_remove_rmap(old_page, true);
-		hugepage_add_new_anon_rmap(new_page, vma, address);
+		hugepage_add_new_anon_rmap(new_page, vma, haddr);
 		/* Make the old page be freed below */
 		new_page = old_page;
 	}
 	spin_unlock(ptl);
 	mmu_notifier_invalidate_range_end(mm, mmun_start, mmun_end);
 out_release_all:
-	restore_reserve_on_error(h, vma, address, new_page);
+	restore_reserve_on_error(h, vma, haddr, new_page);
 	put_page(new_page);
 out_release_old:
 	put_page(old_page);
-- 
2.16.1