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 388fe01de18e845b6be4b27aa36827dd0a15de15..72680a6715fc03bd8d2af4f195e3cfaab298d2d4 100644 (file)
--- a/block/cfq-iosched.c
+++ b/block/cfq-iosched.c
@@ -3656,7 +3656,7 @@ static void cfq_exit_queue(struct elevator_queue *e)
        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 @@ static void *cfq_init_queue(struct request_queue *q)
 
        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 @@ static void *cfq_init_queue(struct request_queue *q)
        if (blkio_alloc_blkg_stats(&cfqg->blkg)) {
                kfree(cfqg);
                kfree(cfqd);
-               return NULL;
+               return -ENOMEM;
        }
 
        rcu_read_lock();
@@ -3723,6 +3723,7 @@ static void *cfq_init_queue(struct request_queue *q)
        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 @@ static void *cfq_init_queue(struct request_queue *q)
         * 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 7bf12d793fcdee25eb1ba178a59203b72d60ec2e..599b12e5380f50aa32e35ec3096b035437842805 100644 (file)
--- a/block/deadline-iosched.c
+++ b/block/deadline-iosched.c
@@ -337,13 +337,13 @@ static void deadline_exit_queue(struct elevator_queue *e)
 /*
  * 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 @@ static void *deadline_init_queue(struct request_queue *q)
        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 f8c08e1bff2bf16b9277c30717216d653cd73cde..f81c061dad15a70e9da71420ad3ad463ad3a8410 100644 (file)
--- a/block/elevator.c
+++ b/block/elevator.c
@@ -121,14 +121,6 @@ static struct elevator_type *elevator_get(const char *name)
        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 @@ int elevator_init(struct request_queue *q, char *name)
        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 @@ static int elevator_switch(struct request_queue *q, struct elevator_type *new_e)
        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 413a0b1d788c745df932745a65adb36ec119afaa..5d1bf70e33d5a04a5fc994c8a8cb0c9ecdbf0900 100644 (file)
--- a/block/noop-iosched.c
+++ b/block/noop-iosched.c
@@ -59,15 +59,17 @@ noop_latter_request(struct request_queue *q, struct request *rq)
        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 7d4e0356f329253f8932e712693544d31e01cacd..97fb2557a18ca27ee15c0781cfae6e8e6e51adca 100644 (file)
--- a/include/linux/elevator.h
+++ b/include/linux/elevator.h
@@ -33,7 +33,7 @@ typedef void (elevator_put_req_fn) (struct request *);
 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