mm: multi-gen LRU: clean up sysfs code

This patch cleans up the sysfs code. Specifically,
  1. use sysfs_emit(),
  2. use __ATTR_RW(), and
  3. constify multi-gen LRU struct attribute_group.

Link: https://lkml.kernel.org/r/20230214035445.1250139-1-talumbau@google.comSigned-off-by: T.J. Alumbaugh <talumbau@google.com>
Cc: Yu Zhao <yuzhao@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

include/linux/mmzone.h

@@ -1369,7 +1369,7 @@ typedef struct pglist_data {
 
 #ifdef CONFIG_LRU_GEN
 	/* kswap mm walk data */
-	struct lru_gen_mm_walk	mm_walk;
+	struct lru_gen_mm_walk mm_walk;
 	/* lru_gen_folio list */
 	struct lru_gen_memcg memcg_lru;
 #endif

mm/vmscan.c

@@ -5663,14 +5663,14 @@ static void lru_gen_change_state(bool enabled)
  *                          sysfs interface
  ******************************************************************************/
 
-static ssize_t show_min_ttl(struct kobject *kobj, struct kobj_attribute *attr, char *buf)
+static ssize_t min_ttl_ms_show(struct kobject *kobj, struct kobj_attribute *attr, char *buf)
 {
-	return sprintf(buf, "%u\n", jiffies_to_msecs(READ_ONCE(lru_gen_min_ttl)));
+	return sysfs_emit(buf, "%u\n", jiffies_to_msecs(READ_ONCE(lru_gen_min_ttl)));
 }
 
 /* see Documentation/admin-guide/mm/multigen_lru.rst for details */
-static ssize_t store_min_ttl(struct kobject *kobj, struct kobj_attribute *attr,
-			     const char *buf, size_t len)
+static ssize_t min_ttl_ms_store(struct kobject *kobj, struct kobj_attribute *attr,
+				const char *buf, size_t len)
 {
 	unsigned int msecs;
 
@@ -5682,11 +5682,9 @@ static ssize_t store_min_ttl(struct kobject *kobj, struct kobj_attribute *attr,
 	return len;
 }
 
-static struct kobj_attribute lru_gen_min_ttl_attr = __ATTR(
-	min_ttl_ms, 0644, show_min_ttl, store_min_ttl
-);
+static struct kobj_attribute lru_gen_min_ttl_attr = __ATTR_RW(min_ttl_ms);
 
-static ssize_t show_enabled(struct kobject *kobj, struct kobj_attribute *attr, char *buf)
+static ssize_t enabled_show(struct kobject *kobj, struct kobj_attribute *attr, char *buf)
 {
 	unsigned int caps = 0;
 
@@ -5703,7 +5701,7 @@ static ssize_t show_enabled(struct kobject *kobj, struct kobj_attribute *attr, c
 }
 
 /* see Documentation/admin-guide/mm/multigen_lru.rst for details */
-static ssize_t store_enabled(struct kobject *kobj, struct kobj_attribute *attr,
+static ssize_t enabled_store(struct kobject *kobj, struct kobj_attribute *attr,
 			     const char *buf, size_t len)
 {
 	int i;
@@ -5730,9 +5728,7 @@ static ssize_t store_enabled(struct kobject *kobj, struct kobj_attribute *attr,
 	return len;
 }
 
-static struct kobj_attribute lru_gen_enabled_attr = __ATTR(
-	enabled, 0644, show_enabled, store_enabled
-);
+static struct kobj_attribute lru_gen_enabled_attr = __ATTR_RW(enabled);
 
 static struct attribute *lru_gen_attrs[] = {
 	&lru_gen_min_ttl_attr.attr,
@@ -5740,7 +5736,7 @@ static struct attribute *lru_gen_attrs[] = {
 	NULL
 };
 
-static struct attribute_group lru_gen_attr_group = {
+static const struct attribute_group lru_gen_attr_group = {
 	.name = "lru_gen",
 	.attrs = lru_gen_attrs,
 };