thp: cleanup: introduce mk_huge_pmd()

Introduce mk_huge_pmd() to simplify the code
Signed-off-by: Bob Liu <lliubbo@gmail.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Michal Hocko <mhocko@suse.cz>
Cc: Minchan Kim <minchan.kim@gmail.com>
Cc: Ni zhan Chen <nizhan.chen@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

mm/huge_memory.c

@@ -606,6 +606,15 @@ static inline pmd_t maybe_pmd_mkwrite(pmd_t pmd, struct vm_area_struct *vma)
 	return pmd;
 }
 
+static inline pmd_t mk_huge_pmd(struct page *page, struct vm_area_struct *vma)
+{
+	pmd_t entry;
+	entry = mk_pmd(page, vma->vm_page_prot);
+	entry = maybe_pmd_mkwrite(pmd_mkdirty(entry), vma);
+	entry = pmd_mkhuge(entry);
+	return entry;
+}
+
 static int __do_huge_pmd_anonymous_page(struct mm_struct *mm,
 					struct vm_area_struct *vma,
 					unsigned long haddr, pmd_t *pmd,
@@ -629,9 +638,7 @@ static int __do_huge_pmd_anonymous_page(struct mm_struct *mm,
 		pte_free(mm, pgtable);
 	} else {
 		pmd_t entry;
-		entry = mk_pmd(page, vma->vm_page_prot);
-		entry = maybe_pmd_mkwrite(pmd_mkdirty(entry), vma);
-		entry = pmd_mkhuge(entry);
+		entry = mk_huge_pmd(page, vma);
 		/*
 		 * The spinlocking to take the lru_lock inside
 		 * page_add_new_anon_rmap() acts as a full memory
@@ -951,9 +958,7 @@ int do_huge_pmd_wp_page(struct mm_struct *mm, struct vm_area_struct *vma,
 	} else {
 		pmd_t entry;
 		VM_BUG_ON(!PageHead(page));
-		entry = mk_pmd(new_page, vma->vm_page_prot);
-		entry = maybe_pmd_mkwrite(pmd_mkdirty(entry), vma);
-		entry = pmd_mkhuge(entry);
+		entry = mk_huge_pmd(new_page, vma);
 		pmdp_clear_flush(vma, haddr, pmd);
 		page_add_new_anon_rmap(new_page, vma, haddr);
 		set_pmd_at(mm, haddr, pmd, entry);
@@ -2000,9 +2005,7 @@ static void collapse_huge_page(struct mm_struct *mm,
 	__SetPageUptodate(new_page);
 	pgtable = pmd_pgtable(_pmd);
 
-	_pmd = mk_pmd(new_page, vma->vm_page_prot);
-	_pmd = maybe_pmd_mkwrite(pmd_mkdirty(_pmd), vma);
-	_pmd = pmd_mkhuge(_pmd);
+	_pmd = mk_huge_pmd(new_page, vma);
 
 	/*
 	 * spin_lock() below is not the equivalent of smp_wmb(), so