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-rw-r--r--block/elevator.c12
1 files changed, 8 insertions, 4 deletions
diff --git a/block/elevator.c b/block/elevator.c
index 205b09a5bd9e..4e11559aa2b0 100644
--- a/block/elevator.c
+++ b/block/elevator.c
@@ -938,6 +938,7 @@ int elv_register_queue(struct request_queue *q)
}
}
kobject_uevent(&e->kobj, KOBJ_ADD);
+ e->registered = 1;
}
return error;
}
@@ -947,6 +948,7 @@ static void __elv_unregister_queue(struct elevator_queue *e)
{
kobject_uevent(&e->kobj, KOBJ_REMOVE);
kobject_del(&e->kobj);
+ e->registered = 0;
}
void elv_unregister_queue(struct request_queue *q)
@@ -1042,11 +1044,13 @@ static int elevator_switch(struct request_queue *q, struct elevator_type *new_e)
spin_unlock_irq(q->queue_lock);
- __elv_unregister_queue(old_elevator);
+ if (old_elevator->registered) {
+ __elv_unregister_queue(old_elevator);
- err = elv_register_queue(q);
- if (err)
- goto fail_register;
+ err = elv_register_queue(q);
+ if (err)
+ goto fail_register;
+ }
/*
* finally exit old elevator and turn off BYPASS.