diff options
| -rw-r--r-- | block/elevator.c | 91 |
1 files changed, 37 insertions, 54 deletions
diff --git a/block/elevator.c b/block/elevator.c index 6a343e8f8319..a16c2d1713e5 100644 --- a/block/elevator.c +++ b/block/elevator.c @@ -168,17 +168,13 @@ static struct elevator_type *elevator_get(const char *name) return e; } -static void *elevator_init_queue(struct request_queue *q, - struct elevator_queue *eq) +static int elevator_init_queue(struct request_queue *q, + struct elevator_queue *eq) { - return eq->ops->elevator_init_fn(q); -} - -static void elevator_attach(struct request_queue *q, struct elevator_queue *eq, - void *data) -{ - q->elevator = eq; - eq->elevator_data = data; + eq->elevator_data = eq->ops->elevator_init_fn(q); + if (eq->elevator_data) + return 0; + return -ENOMEM; } static char chosen_elevator[ELV_NAME_MAX]; @@ -241,7 +237,7 @@ int elevator_init(struct request_queue *q, char *name) { struct elevator_type *e = NULL; struct elevator_queue *eq; - void *data; + int err; if (unlikely(q->elevator)) return 0; @@ -278,13 +274,13 @@ int elevator_init(struct request_queue *q, char *name) if (!eq) return -ENOMEM; - data = elevator_init_queue(q, eq); - if (!data) { + err = elevator_init_queue(q, eq); + if (err) { kobject_put(&eq->kobj); - return -ENOMEM; + return err; } - elevator_attach(q, eq, data); + q->elevator = eq; return 0; } EXPORT_SYMBOL(elevator_init); @@ -856,9 +852,8 @@ static struct kobj_type elv_ktype = { .release = elevator_release, }; -int elv_register_queue(struct request_queue *q) +int __elv_register_queue(struct request_queue *q, struct elevator_queue *e) { - struct elevator_queue *e = q->elevator; int error; error = kobject_add(&e->kobj, &q->kobj, "%s", "iosched"); @@ -876,19 +871,22 @@ int elv_register_queue(struct request_queue *q) } return error; } -EXPORT_SYMBOL(elv_register_queue); -static void __elv_unregister_queue(struct elevator_queue *e) +int elv_register_queue(struct request_queue *q) { - kobject_uevent(&e->kobj, KOBJ_REMOVE); - kobject_del(&e->kobj); - e->registered = 0; + return __elv_register_queue(q, q->elevator); } +EXPORT_SYMBOL(elv_register_queue); void elv_unregister_queue(struct request_queue *q) { - if (q) - __elv_unregister_queue(q->elevator); + if (q) { + struct elevator_queue *e = q->elevator; + + kobject_uevent(&e->kobj, KOBJ_REMOVE); + kobject_del(&e->kobj); + e->registered = 0; + } } EXPORT_SYMBOL(elv_unregister_queue); @@ -928,50 +926,36 @@ EXPORT_SYMBOL_GPL(elv_unregister); static int elevator_switch(struct request_queue *q, struct elevator_type *new_e) { struct elevator_queue *old_elevator, *e; - void *data; int err; - /* - * Allocate new elevator - */ + /* allocate new elevator */ e = elevator_alloc(q, new_e); if (!e) return -ENOMEM; - data = elevator_init_queue(q, e); - if (!data) { + err = elevator_init_queue(q, e); + if (err) { kobject_put(&e->kobj); - return -ENOMEM; + return err; } - /* - * Turn on BYPASS and drain all requests w/ elevator private data - */ + /* turn on BYPASS and drain all requests w/ elevator private data */ elv_quiesce_start(q); - /* - * Remember old elevator. - */ - old_elevator = q->elevator; - - /* - * attach and start new elevator - */ - spin_lock_irq(q->queue_lock); - elevator_attach(q, e, data); - spin_unlock_irq(q->queue_lock); - - if (old_elevator->registered) { - __elv_unregister_queue(old_elevator); - - err = elv_register_queue(q); + /* unregister old queue, register new one and kill old elevator */ + if (q->elevator->registered) { + elv_unregister_queue(q); + err = __elv_register_queue(q, e); if (err) goto fail_register; } - /* - * finally exit old elevator and turn off BYPASS. - */ + /* done, replace the old one with new one and turn off BYPASS */ + spin_lock_irq(q->queue_lock); + old_elevator = q->elevator; + q->elevator = e; + spin_unlock_irq(q->queue_lock); + elevator_exit(old_elevator); elv_quiesce_end(q); @@ -985,7 +969,6 @@ fail_register: * one again (along with re-adding the sysfs dir) */ elevator_exit(e); - q->elevator = old_elevator; elv_register_queue(q); elv_quiesce_end(q); |