elevator: Enable const sysfs attributes

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@weissschuh.net>
Link: https://lore.kernel.org/r/20250102-sysfs-const-attr-elevator-v1-1-9837d2058c60@weissschuh.net
Signed-off-by: Jens Axboe <axboe@kernel.dk>

diff --git a/block/elevator.c b/block/elevator.c
index a26b966626202b54effdccc3d2c91abe68599ecc..be6e994256ac8a09971e3ebb95153af22adb6650 100644 (file)
--- 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 (file)
--- 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;