[PATCH 1/4] elevator: Enable const sysfs attributes

[Thomas Weißschuh <linux@xxxxxxxxxxxxxx>]

The elevator core does not need to modify the sysfs attributes added by
the elevators. Reflect this in the types, so the attributes can be moved
into read-only memory.

Signed-off-by: Thomas Weißschuh <linux@xxxxxxxxxxxxxx>
---
 block/elevator.c | 8 ++++----
 block/elevator.h | 2 +-
 2 files changed, 5 insertions(+), 5 deletions(-)

diff --git a/block/elevator.c b/block/elevator.c
index 7c3ba80e5ff4a390e62bb4318d364e95da92cd3c..0254ff79a696032e032781c4d9519e9ab7f52cb7 100644
--- a/block/elevator.c
+++ b/block/elevator.c
@@ -405,12 +405,12 @@ struct request *elv_former_request(struct request_queue *q, struct request *rq)
 	return NULL;
 }
 
-#define to_elv(atr) container_of((atr), struct elv_fs_entry, attr)
+#define to_elv(atr) container_of_const((atr), struct elv_fs_entry, attr)
 
 static ssize_t
 elv_attr_show(struct kobject *kobj, struct attribute *attr, char *page)
 {
-	struct elv_fs_entry *entry = to_elv(attr);
+	const struct elv_fs_entry *entry = to_elv(attr);
 	struct elevator_queue *e;
 	ssize_t error;
 
@@ -428,7 +428,7 @@ static ssize_t
 elv_attr_store(struct kobject *kobj, struct attribute *attr,
 	       const char *page, size_t length)
 {
-	struct elv_fs_entry *entry = to_elv(attr);
+	const struct elv_fs_entry *entry = to_elv(attr);
 	struct elevator_queue *e;
 	ssize_t error;
 
@@ -461,7 +461,7 @@ int elv_register_queue(struct request_queue *q, bool uevent)
 
 	error = kobject_add(&e->kobj, &q->disk->queue_kobj, "iosched");
 	if (!error) {
-		struct elv_fs_entry *attr = e->type->elevator_attrs;
+		const struct elv_fs_entry *attr = e->type->elevator_attrs;
 		if (attr) {
 			while (attr->attr.name) {
 				if (sysfs_create_file(&e->kobj, &attr->attr))
diff --git a/block/elevator.h b/block/elevator.h
index dbf357ef4fab9362b7fb2f53724b6bea2ff057b7..e526662c5dbb1f313cb2346b72f713e1cd58665e 100644
--- a/block/elevator.h
+++ b/block/elevator.h
@@ -71,7 +71,7 @@ struct elevator_type
 
 	size_t icq_size;	/* see iocontext.h */
 	size_t icq_align;	/* ditto */
-	struct elv_fs_entry *elevator_attrs;
+	const struct elv_fs_entry *elevator_attrs;
 	const char *elevator_name;
 	const char *elevator_alias;
 	struct module *elevator_owner;

-- 
2.47.1