mm/compaction: use DEVICE_ATTR_WO macro

Use DEVICE_ATTR_WO helper instead of plain DEVICE_ATTR, which makes the
code a bit shorter and easier to read.

Link: https://lkml.kernel.org/r/20210523064521.32912-1-yuehaibing@huawei.comSigned-off-by: YueHaibing <yuehaibing@huawei.com>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

mm/compaction.c

@@ -2722,9 +2722,9 @@ int sysctl_compaction_handler(struct ctl_table *table, int write,
 }
 
 #if defined(CONFIG_SYSFS) && defined(CONFIG_NUMA)
-static ssize_t sysfs_compact_node(struct device *dev,
-			struct device_attribute *attr,
-			const char *buf, size_t count)
+static ssize_t compact_store(struct device *dev,
+			     struct device_attribute *attr,
+			     const char *buf, size_t count)
 {
 	int nid = dev->id;
 
@@ -2737,7 +2737,7 @@ static ssize_t sysfs_compact_node(struct device *dev,
 
 	return count;
 }
-static DEVICE_ATTR(compact, 0200, NULL, sysfs_compact_node);
+static DEVICE_ATTR_WO(compact);
 
 int compaction_register_node(struct node *node)
 {