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-rw-r--r--block/noop-iosched.c85
1 files changed, 79 insertions, 6 deletions
diff --git a/block/noop-iosched.c b/block/noop-iosched.c
index e54f006..f370e4a 100644
--- a/block/noop-iosched.c
+++ b/block/noop-iosched.c
@@ -7,21 +7,94 @@
#include <linux/module.h>
#include <linux/init.h>
-static void elevator_noop_add_request(request_queue_t *q, struct request *rq)
+struct noop_data {
+ struct list_head queue;
+};
+
+static void noop_merged_requests(request_queue_t *q, struct request *rq,
+ struct request *next)
+{
+ list_del_init(&next->queuelist);
+}
+
+static int noop_dispatch(request_queue_t *q, int force)
+{
+ struct noop_data *nd = q->elevator->elevator_data;
+
+ if (!list_empty(&nd->queue)) {
+ struct request *rq;
+ rq = list_entry(nd->queue.next, struct request, queuelist);
+ list_del_init(&rq->queuelist);
+ elv_dispatch_sort(q, rq);
+ return 1;
+ }
+ return 0;
+}
+
+static void noop_add_request(request_queue_t *q, struct request *rq)
+{
+ struct noop_data *nd = q->elevator->elevator_data;
+
+ list_add_tail(&rq->queuelist, &nd->queue);
+}
+
+static int noop_queue_empty(request_queue_t *q)
{
- rq->flags |= REQ_NOMERGE;
- elv_dispatch_add_tail(q, rq);
+ struct noop_data *nd = q->elevator->elevator_data;
+
+ return list_empty(&nd->queue);
+}
+
+static struct request *
+noop_former_request(request_queue_t *q, struct request *rq)
+{
+ struct noop_data *nd = q->elevator->elevator_data;
+
+ if (rq->queuelist.prev == &nd->queue)
+ return NULL;
+ return list_entry(rq->queuelist.prev, struct request, queuelist);
+}
+
+static struct request *
+noop_latter_request(request_queue_t *q, struct request *rq)
+{
+ struct noop_data *nd = q->elevator->elevator_data;
+
+ if (rq->queuelist.next == &nd->queue)
+ return NULL;
+ return list_entry(rq->queuelist.next, struct request, queuelist);
}
-static int elevator_noop_dispatch(request_queue_t *q, int force)
+static int noop_init_queue(request_queue_t *q, elevator_t *e)
{
+ struct noop_data *nd;
+
+ nd = kmalloc(sizeof(*nd), GFP_KERNEL);
+ if (!nd)
+ return -ENOMEM;
+ INIT_LIST_HEAD(&nd->queue);
+ e->elevator_data = nd;
return 0;
}
+static void noop_exit_queue(elevator_t *e)
+{
+ struct noop_data *nd = e->elevator_data;
+
+ BUG_ON(!list_empty(&nd->queue));
+ kfree(nd);
+}
+
static struct elevator_type elevator_noop = {
.ops = {
- .elevator_dispatch_fn = elevator_noop_dispatch,
- .elevator_add_req_fn = elevator_noop_add_request,
+ .elevator_merge_req_fn = noop_merged_requests,
+ .elevator_dispatch_fn = noop_dispatch,
+ .elevator_add_req_fn = noop_add_request,
+ .elevator_queue_empty_fn = noop_queue_empty,
+ .elevator_former_req_fn = noop_former_request,
+ .elevator_latter_req_fn = noop_latter_request,
+ .elevator_init_fn = noop_init_queue,
+ .elevator_exit_fn = noop_exit_queue,
},
.elevator_name = "noop",
.elevator_owner = THIS_MODULE,