mm: remove call to find_vma in pagewalk for non-hugetlbfs

Commit d33b9f4 ("mm: hugetlb: fix hugepage memory leak in
walk_page_range()") introduces a check if a vma is a hugetlbfs one and
later in 5dc3764 ("mm hugetlb: add hugepage support to pagemap") it is
moved under #ifdef CONFIG_HUGETLB_PAGE but a needless find_vma call is
left behind and its result is not used anywhere else in the function.

The side-effect of caching vma for @addr inside walk->mm is neither
utilized in walk_page_range() nor in called functions.

Signed-off-by: David Sterba <[email protected]>
Reviewed-by: Naoya Horiguchi <[email protected]>
Acked-by: Andi Kleen <[email protected]>
Cc: Andy Whitcroft <[email protected]>
Cc: David Rientjes <[email protected]>
Cc: Hugh Dickins <[email protected]>
Cc: Lee Schermerhorn <[email protected]>
Cc: Matt Mackall <[email protected]>
Acked-by: Mel Gorman <[email protected]>
Cc: Wu Fengguang <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>

mm/pagewalk.c

@@ -139,7 +139,6 @@ int walk_page_range(unsigned long addr, unsigned long end,
 	pgd_t *pgd;
 	unsigned long next;
 	int err = 0;
-	struct vm_area_struct *vma;
 
 	if (addr >= end)
 		return err;
@@ -149,15 +148,17 @@ int walk_page_range(unsigned long addr, unsigned long end,
 
 	pgd = pgd_offset(walk->mm, addr);
 	do {
+		struct vm_area_struct *uninitialized_var(vma);
+
 		next = pgd_addr_end(addr, end);
 
+#ifdef CONFIG_HUGETLB_PAGE
 		/*
 		 * handle hugetlb vma individually because pagetable walk for
 		 * the hugetlb page is dependent on the architecture and
 		 * we can't handled it in the same manner as non-huge pages.
 		 */
 		vma = find_vma(walk->mm, addr);
-#ifdef CONFIG_HUGETLB_PAGE
 		if (vma && is_vm_hugetlb_page(vma)) {
 			if (vma->vm_end < next)
 				next = vma->vm_end;