elevator: make elevator_init_fn() return 0/-errno
elevator_ops->elevator_init_fn() has a weird return value. It returns
a void * which the caller should assign to q->elevator->elevator_data
and %NULL return denotes init failure.
Update such that it returns integer 0/-errno and sets elevator_data
directly as necessary.
This makes the interface more conventional and eases further cleanup.
Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Vivek Goyal <vgoyal@redhat.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
diff --git a/block/cfq-iosched.c b/block/cfq-iosched.c
index 388fe01..72680a6 100644
--- a/block/cfq-iosched.c
+++ b/block/cfq-iosched.c
@@ -3656,7 +3656,7 @@
kfree(cfqd);
}
-static void *cfq_init_queue(struct request_queue *q)
+static int cfq_init_queue(struct request_queue *q)
{
struct cfq_data *cfqd;
int i, j;
@@ -3665,7 +3665,7 @@
cfqd = kmalloc_node(sizeof(*cfqd), GFP_KERNEL | __GFP_ZERO, q->node);
if (!cfqd)
- return NULL;
+ return -ENOMEM;
/* Init root service tree */
cfqd->grp_service_tree = CFQ_RB_ROOT;
@@ -3692,7 +3692,7 @@
if (blkio_alloc_blkg_stats(&cfqg->blkg)) {
kfree(cfqg);
kfree(cfqd);
- return NULL;
+ return -ENOMEM;
}
rcu_read_lock();
@@ -3723,6 +3723,7 @@
cfq_link_cfqq_cfqg(&cfqd->oom_cfqq, &cfqd->root_group);
cfqd->queue = q;
+ q->elevator->elevator_data = cfqd;
init_timer(&cfqd->idle_slice_timer);
cfqd->idle_slice_timer.function = cfq_idle_slice_timer;
@@ -3747,7 +3748,7 @@
* second, in order to have larger depth for async operations.
*/
cfqd->last_delayed_sync = jiffies - HZ;
- return cfqd;
+ return 0;
}
/*
diff --git a/block/deadline-iosched.c b/block/deadline-iosched.c
index 7bf12d7..599b12e 100644
--- a/block/deadline-iosched.c
+++ b/block/deadline-iosched.c
@@ -337,13 +337,13 @@
/*
* initialize elevator private data (deadline_data).
*/
-static void *deadline_init_queue(struct request_queue *q)
+static int deadline_init_queue(struct request_queue *q)
{
struct deadline_data *dd;
dd = kmalloc_node(sizeof(*dd), GFP_KERNEL | __GFP_ZERO, q->node);
if (!dd)
- return NULL;
+ return -ENOMEM;
INIT_LIST_HEAD(&dd->fifo_list[READ]);
INIT_LIST_HEAD(&dd->fifo_list[WRITE]);
@@ -354,7 +354,9 @@
dd->writes_starved = writes_starved;
dd->front_merges = 1;
dd->fifo_batch = fifo_batch;
- return dd;
+
+ q->elevator->elevator_data = dd;
+ return 0;
}
/*
diff --git a/block/elevator.c b/block/elevator.c
index f8c08e1..f81c061 100644
--- a/block/elevator.c
+++ b/block/elevator.c
@@ -121,14 +121,6 @@
return e;
}
-static int elevator_init_queue(struct request_queue *q)
-{
- q->elevator->elevator_data = q->elevator->type->ops.elevator_init_fn(q);
- if (q->elevator->elevator_data)
- return 0;
- return -ENOMEM;
-}
-
static char chosen_elevator[ELV_NAME_MAX];
static int __init elevator_setup(char *str)
@@ -224,7 +216,7 @@
if (!q->elevator)
return -ENOMEM;
- err = elevator_init_queue(q);
+ err = e->ops.elevator_init_fn(q);
if (err) {
kobject_put(&q->elevator->kobj);
return err;
@@ -927,7 +919,7 @@
if (!q->elevator)
goto fail_init;
- err = elevator_init_queue(q);
+ err = new_e->ops.elevator_init_fn(q);
if (err) {
kobject_put(&q->elevator->kobj);
goto fail_init;
diff --git a/block/noop-iosched.c b/block/noop-iosched.c
index 413a0b1..5d1bf70 100644
--- a/block/noop-iosched.c
+++ b/block/noop-iosched.c
@@ -59,15 +59,17 @@
return list_entry(rq->queuelist.next, struct request, queuelist);
}
-static void *noop_init_queue(struct request_queue *q)
+static int noop_init_queue(struct request_queue *q)
{
struct noop_data *nd;
nd = kmalloc_node(sizeof(*nd), GFP_KERNEL, q->node);
if (!nd)
- return NULL;
+ return -ENOMEM;
+
INIT_LIST_HEAD(&nd->queue);
- return nd;
+ q->elevator->elevator_data = nd;
+ return 0;
}
static void noop_exit_queue(struct elevator_queue *e)
diff --git a/include/linux/elevator.h b/include/linux/elevator.h
index 7d4e035..97fb255 100644
--- a/include/linux/elevator.h
+++ b/include/linux/elevator.h
@@ -33,7 +33,7 @@
typedef void (elevator_activate_req_fn) (struct request_queue *, struct request *);
typedef void (elevator_deactivate_req_fn) (struct request_queue *, struct request *);
-typedef void *(elevator_init_fn) (struct request_queue *);
+typedef int (elevator_init_fn) (struct request_queue *);
typedef void (elevator_exit_fn) (struct elevator_queue *);
struct elevator_ops