mm: hugetlb: cleanup duplicated code in unmapping vm range

Fix code duplication in __unmap_hugepage_range(), such as pte_page() and
huge_pte_none().
Signed-off-by: Hillf Danton <dhillf@gmail.com>
Cc: Michal Hocko <mhocko@suse.cz>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Hugh Dickins <hughd@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

mm/hugetlb.c

@@ -2331,16 +2331,23 @@ void __unmap_hugepage_range(struct vm_area_struct *vma, unsigned long start,
 		if (huge_pmd_unshare(mm, &address, ptep))
 			continue;
 
+		pte = huge_ptep_get(ptep);
+		if (huge_pte_none(pte))
+			continue;
+
+		/*
+		 * HWPoisoned hugepage is already unmapped and dropped reference
+		 */
+		if (unlikely(is_hugetlb_entry_hwpoisoned(pte)))
+			continue;
+
+		page = pte_page(pte);
 		/*
 		 * If a reference page is supplied, it is because a specific
 		 * page is being unmapped, not a range. Ensure the page we
 		 * are about to unmap is the actual page of interest.
 		 */
 		if (ref_page) {
-			pte = huge_ptep_get(ptep);
-			if (huge_pte_none(pte))
-				continue;
-			page = pte_page(pte);
 			if (page != ref_page)
 				continue;
 
@@ -2353,16 +2360,6 @@ void __unmap_hugepage_range(struct vm_area_struct *vma, unsigned long start,
 		}
 
 		pte = huge_ptep_get_and_clear(mm, address, ptep);
-		if (huge_pte_none(pte))
-			continue;
-
-		/*
-		 * HWPoisoned hugepage is already unmapped and dropped reference
-		 */
-		if (unlikely(is_hugetlb_entry_hwpoisoned(pte)))
-			continue;
-
-		page = pte_page(pte);
 		if (pte_dirty(pte))
 			set_page_dirty(page);
 		list_add(&page->lru, &page_list);