struct elevator_type *e = NULL;
struct list_head *entry;
- spin_lock_irq(&elv_list_lock);
list_for_each(entry, &elv_list) {
struct elevator_type *__e;
break;
}
}
- spin_unlock_irq(&elv_list_lock);
return e;
}
static struct elevator_type *elevator_get(const char *name)
{
- struct elevator_type *e = elevator_find(name);
+ struct elevator_type *e;
- if (!e)
- return NULL;
- if (!try_module_get(e->elevator_owner))
- return NULL;
+ spin_lock_irq(&elv_list_lock);
+
+ e = elevator_find(name);
+ if (e && !try_module_get(e->elevator_owner))
+ e = NULL;
+
+ spin_unlock_irq(&elv_list_lock);
return e;
}
static void elevator_setup_default(void)
{
+ struct elevator_type *e;
+
/*
* check if default is set and exists
*/
- if (chosen_elevator[0] && elevator_find(chosen_elevator))
+ if (chosen_elevator[0] && (e = elevator_get(chosen_elevator))) {
+ elevator_put(e);
return;
+ }
#if defined(CONFIG_IOSCHED_AS)
strcpy(chosen_elevator, "anticipatory");
rq = rq->end_io_data;
}
+ /*
+ * the request is prepped and may have some resources allocated.
+ * allowing unprepped requests to pass this one may cause resource
+ * deadlock. turn on softbarrier.
+ */
+ rq->flags |= REQ_SOFTBARRIER;
+
/*
* if iosched has an explicit requeue hook, then use that. otherwise
* just put the request at the front of the queue
if (ret == BLKPREP_OK) {
break;
} else if (ret == BLKPREP_DEFER) {
+ /*
+ * the request may have been (partially) prepped.
+ * we need to keep this request in the front to
+ * avoid resource deadlock. turn on softbarrier.
+ */
+ rq->flags |= REQ_SOFTBARRIER;
rq = NULL;
break;
} else if (ret == BLKPREP_KILL) {
return NULL;
}
-int elv_set_request(request_queue_t *q, struct request *rq, int gfp_mask)
+int elv_set_request(request_queue_t *q, struct request *rq, struct bio *bio,
+ gfp_t gfp_mask)
{
elevator_t *e = q->elevator;
if (e->ops->elevator_set_req_fn)
- return e->ops->elevator_set_req_fn(q, rq, gfp_mask);
+ return e->ops->elevator_set_req_fn(q, rq, bio, gfp_mask);
rq->elevator_private = NULL;
return 0;
e->ops->elevator_put_req_fn(q, rq);
}
-int elv_may_queue(request_queue_t *q, int rw)
+int elv_may_queue(request_queue_t *q, int rw, struct bio *bio)
{
elevator_t *e = q->elevator;
if (e->ops->elevator_may_queue_fn)
- return e->ops->elevator_may_queue_fn(q, rw);
+ return e->ops->elevator_may_queue_fn(q, rw, bio);
return ELV_MQUEUE_MAY;
}
int elv_register(struct elevator_type *e)
{
+ spin_lock_irq(&elv_list_lock);
if (elevator_find(e->elevator_name))
BUG();
-
- spin_lock_irq(&elv_list_lock);
list_add_tail(&e->list, &elv_list);
spin_unlock_irq(&elv_list_lock);