mm/huge_memory: use helper macro __ATTR_RW

Use helper macro __ATTR_RW to define use_zero_page_attr, defrag_attr and
enabled_attr to make code more clear. Minor readability improvement.

Link: https://lkml.kernel.org/r/20220704132201.14611-9-linmiaohe@huawei.comSigned-off-by: Miaohe Lin <linmiaohe@huawei.com>
Reviewed-by: Muchun Song <songmuchun@bytedance.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Yang Shi <shy828301@gmail.com>
Cc: Zach O'Keefe <zokeefe@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

mm/huge_memory.c

@@ -276,8 +276,8 @@ static ssize_t enabled_store(struct kobject *kobj,
 	}
 	return ret;
 }
-static struct kobj_attribute enabled_attr =
-	__ATTR(enabled, 0644, enabled_show, enabled_store);
+
+static struct kobj_attribute enabled_attr = __ATTR_RW(enabled);
 
 ssize_t single_hugepage_flag_show(struct kobject *kobj,
 				  struct kobj_attribute *attr, char *buf,
@@ -366,8 +366,7 @@ static ssize_t defrag_store(struct kobject *kobj,
 
 	return count;
 }
-static struct kobj_attribute defrag_attr =
-	__ATTR(defrag, 0644, defrag_show, defrag_store);
+static struct kobj_attribute defrag_attr = __ATTR_RW(defrag);
 
 static ssize_t use_zero_page_show(struct kobject *kobj,
 				  struct kobj_attribute *attr, char *buf)
@@ -381,8 +380,7 @@ static ssize_t use_zero_page_store(struct kobject *kobj,
 	return single_hugepage_flag_store(kobj, attr, buf, count,
 				 TRANSPARENT_HUGEPAGE_USE_ZERO_PAGE_FLAG);
 }
-static struct kobj_attribute use_zero_page_attr =
-	__ATTR(use_zero_page, 0644, use_zero_page_show, use_zero_page_store);
+static struct kobj_attribute use_zero_page_attr = __ATTR_RW(use_zero_page);
 
 static ssize_t hpage_pmd_size_show(struct kobject *kobj,
 				   struct kobj_attribute *attr, char *buf)