Pull asus into release branch

[pandora-kernel.git] / block / elevator.c

diff --git a/block/elevator.c b/block/elevator.c
index c0063f3..96a00c8 100644 (file)
--- a/block/elevator.c
+++ b/block/elevator.c
@@ -50,6 +50,21 @@ static const int elv_hash_shift = 6;
 #define rq_hash_key(rq)                ((rq)->sector + (rq)->nr_sectors)
 #define ELV_ON_HASH(rq)                (!hlist_unhashed(&(rq)->hash))
 
+/*
+ * Query io scheduler to see if the current process issuing bio may be
+ * merged with rq.
+ */
+static int elv_iosched_allow_merge(struct request *rq, struct bio *bio)
+{
+       request_queue_t *q = rq->q;
+       elevator_t *e = q->elevator;
+
+       if (e->ops->elevator_allow_merge_fn)
+               return e->ops->elevator_allow_merge_fn(q, rq, bio);
+
+       return 1;
+}
+
 /*
  * can we safely merge with this request?
  */
@@ -65,12 +80,15 @@ inline int elv_rq_merge_ok(struct request *rq, struct bio *bio)
                return 0;
 
        /*
-        * same device and no special stuff set, merge is ok
+        * must be same device and not a special request
         */
-       if (rq->rq_disk == bio->bi_bdev->bd_disk && !rq->special)
-               return 1;
+       if (rq->rq_disk != bio->bi_bdev->bd_disk || rq->special)
+               return 0;
 
-       return 0;
+       if (!elv_iosched_allow_merge(rq, bio))
+               return 0;
+
+       return 1;
 }
 EXPORT_SYMBOL(elv_rq_merge_ok);
 
@@ -251,6 +269,22 @@ void elevator_exit(elevator_t *e)
 
 EXPORT_SYMBOL(elevator_exit);
 
+static void elv_activate_rq(request_queue_t *q, struct request *rq)
+{
+       elevator_t *e = q->elevator;
+
+       if (e->ops->elevator_activate_req_fn)
+               e->ops->elevator_activate_req_fn(q, rq);
+}
+
+static void elv_deactivate_rq(request_queue_t *q, struct request *rq)
+{
+       elevator_t *e = q->elevator;
+
+       if (e->ops->elevator_deactivate_req_fn)
+               e->ops->elevator_deactivate_req_fn(q, rq);
+}
+
 static inline void __elv_rqhash_del(struct request *rq)
 {
        hlist_del_init(&rq->hash);
@@ -379,6 +413,8 @@ void elv_dispatch_sort(request_queue_t *q, struct request *rq)
        list_for_each_prev(entry, &q->queue_head) {
                struct request *pos = list_entry_rq(entry);
 
+               if (rq_data_dir(rq) != rq_data_dir(pos))
+                       break;
                if (pos->cmd_flags & (REQ_SOFTBARRIER|REQ_HARDBARRIER|REQ_STARTED))
                        break;
                if (rq->sector >= boundary) {
@@ -480,16 +516,14 @@ void elv_merge_requests(request_queue_t *q, struct request *rq,
 
 void elv_requeue_request(request_queue_t *q, struct request *rq)
 {
-       elevator_t *e = q->elevator;
-
        /*
         * it already went through dequeue, we need to decrement the
         * in_flight count again
         */
        if (blk_account_rq(rq)) {
                q->in_flight--;
-               if (blk_sorted_rq(rq) && e->ops->elevator_deactivate_req_fn)
-                       e->ops->elevator_deactivate_req_fn(q, rq);
+               if (blk_sorted_rq(rq))
+                       elv_deactivate_rq(q, rq);
        }
 
        rq->cmd_flags &= ~REQ_STARTED;
@@ -572,6 +606,12 @@ void elv_insert(request_queue_t *q, struct request *rq, int where)
                 */
                rq->cmd_flags |= REQ_SOFTBARRIER;
 
+               /*
+                * Most requeues happen because of a busy condition,
+                * don't force unplug of the queue for that case.
+                */
+               unplug_it = 0;
+
                if (q->ordseq == 0) {
                        list_add(&rq->queuelist, &q->queue_head);
                        break;
@@ -586,11 +626,6 @@ void elv_insert(request_queue_t *q, struct request *rq, int where)
                }
 
                list_add_tail(&rq->queuelist, pos);
-               /*
-                * most requeues happen because of a busy condition, don't
-                * force unplug of the queue for that case.
-                */
-               unplug_it = 0;
                break;
 
        default:
@@ -681,16 +716,13 @@ struct request *elv_next_request(request_queue_t *q)
 
        while ((rq = __elv_next_request(q)) != NULL) {
                if (!(rq->cmd_flags & REQ_STARTED)) {
-                       elevator_t *e = q->elevator;
-
                        /*
                         * This is the first time the device driver
                         * sees this request (possibly after
                         * requeueing).  Notify IO scheduler.
                         */
-                       if (blk_sorted_rq(rq) &&
-                           e->ops->elevator_activate_req_fn)
-                               e->ops->elevator_activate_req_fn(q, rq);
+                       if (blk_sorted_rq(rq))
+                               elv_activate_rq(q, rq);
 
                        /*
                         * just mark as started even if we don't start
@@ -932,17 +964,18 @@ void elv_unregister_queue(struct request_queue *q)
 
 int elv_register(struct elevator_type *e)
 {
+       char *def = "";
        spin_lock_irq(&elv_list_lock);
        BUG_ON(elevator_find(e->elevator_name));
        list_add_tail(&e->list, &elv_list);
        spin_unlock_irq(&elv_list_lock);
 
-       printk(KERN_INFO "io scheduler %s registered", e->elevator_name);
        if (!strcmp(e->elevator_name, chosen_elevator) ||
                        (!*chosen_elevator &&
                         !strcmp(e->elevator_name, CONFIG_DEFAULT_IOSCHED)))
-                               printk(" (default)");
-       printk("\n");
+                               def = " (default)";
+
+       printk(KERN_INFO "io scheduler %s registered%s\n", e->elevator_name, def);
        return 0;
 }
 EXPORT_SYMBOL_GPL(elv_register);