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-rw-r--r--block/elevator.c55
1 files changed, 34 insertions, 21 deletions
diff --git a/block/elevator.c b/block/elevator.c
index 8768a36..a0afdd3 100644
--- a/block/elevator.c
+++ b/block/elevator.c
@@ -121,16 +121,16 @@ static struct elevator_type *elevator_get(const char *name)
return e;
}
-static int elevator_attach(request_queue_t *q, struct elevator_queue *eq)
+static void *elevator_init_queue(request_queue_t *q, struct elevator_queue *eq)
{
- int ret = 0;
+ return eq->ops->elevator_init_fn(q, eq);
+}
+static void elevator_attach(request_queue_t *q, struct elevator_queue *eq,
+ void *data)
+{
q->elevator = eq;
-
- if (eq->ops->elevator_init_fn)
- ret = eq->ops->elevator_init_fn(q, eq);
-
- return ret;
+ eq->elevator_data = data;
}
static char chosen_elevator[16];
@@ -181,6 +181,7 @@ int elevator_init(request_queue_t *q, char *name)
struct elevator_type *e = NULL;
struct elevator_queue *eq;
int ret = 0;
+ void *data;
INIT_LIST_HEAD(&q->queue_head);
q->last_merge = NULL;
@@ -202,10 +203,13 @@ int elevator_init(request_queue_t *q, char *name)
if (!eq)
return -ENOMEM;
- ret = elevator_attach(q, eq);
- if (ret)
+ data = elevator_init_queue(q, eq);
+ if (!data) {
kobject_put(&eq->kobj);
+ return -ENOMEM;
+ }
+ elevator_attach(q, eq, data);
return ret;
}
@@ -722,13 +726,16 @@ int elv_register_queue(struct request_queue *q)
return error;
}
+static void __elv_unregister_queue(elevator_t *e)
+{
+ kobject_uevent(&e->kobj, KOBJ_REMOVE);
+ kobject_del(&e->kobj);
+}
+
void elv_unregister_queue(struct request_queue *q)
{
- if (q) {
- elevator_t *e = q->elevator;
- kobject_uevent(&e->kobj, KOBJ_REMOVE);
- kobject_del(&e->kobj);
- }
+ if (q)
+ __elv_unregister_queue(q->elevator);
}
int elv_register(struct elevator_type *e)
@@ -780,6 +787,7 @@ EXPORT_SYMBOL_GPL(elv_unregister);
static int elevator_switch(request_queue_t *q, struct elevator_type *new_e)
{
elevator_t *old_elevator, *e;
+ void *data;
/*
* Allocate new elevator
@@ -788,6 +796,12 @@ static int elevator_switch(request_queue_t *q, struct elevator_type *new_e)
if (!e)
return 0;
+ data = elevator_init_queue(q, e);
+ if (!data) {
+ kobject_put(&e->kobj);
+ return 0;
+ }
+
/*
* Turn on BYPASS and drain all requests w/ elevator private data
*/
@@ -806,19 +820,19 @@ static int elevator_switch(request_queue_t *q, struct elevator_type *new_e)
elv_drain_elevator(q);
}
- spin_unlock_irq(q->queue_lock);
-
/*
- * unregister old elevator data
+ * Remember old elevator.
*/
- elv_unregister_queue(q);
old_elevator = q->elevator;
/*
* attach and start new elevator
*/
- if (elevator_attach(q, e))
- goto fail;
+ elevator_attach(q, e, data);
+
+ spin_unlock_irq(q->queue_lock);
+
+ __elv_unregister_queue(old_elevator);
if (elv_register_queue(q))
goto fail_register;
@@ -837,7 +851,6 @@ fail_register:
*/
elevator_exit(e);
e = NULL;
-fail:
q->elevator = old_elevator;
elv_register_queue(q);
clear_bit(QUEUE_FLAG_ELVSWITCH, &q->queue_flags);