block cfq: don't use atomic_t for cfq_group

[mv-sheeva.git] / block / cfq-iosched.c

diff --git a/block/cfq-iosched.c b/block/cfq-iosched.c
index 9b186fd6bf477f3cb95a9b3e4835178abaeb9a7c..f083bda3054647f3ca30cda9d66d9223fb8a500d 100644 (file)
--- a/block/cfq-iosched.c
+++ b/block/cfq-iosched.c
@@ -96,7 +96,7 @@ struct cfq_rb_root {
  */
 struct cfq_queue {
        /* reference count */
-       atomic_t ref;
+       int ref;
        /* various state flags, see below */
        unsigned int flags;
        /* parent cfq_data */
@@ -207,7 +207,7 @@ struct cfq_group {
        struct blkio_group blkg;
 #ifdef CONFIG_CFQ_GROUP_IOSCHED
        struct hlist_node cfqd_node;
-       atomic_t ref;
+       int ref;
 #endif
        /* number of requests that are on the dispatch list or inside driver */
        int dispatched;
@@ -1014,7 +1014,7 @@ cfq_find_alloc_cfqg(struct cfq_data *cfqd, struct cgroup *cgroup, int create)
         * elevator which will be dropped by either elevator exit
         * or cgroup deletion path depending on who is exiting first.
         */
-       atomic_set(&cfqg->ref, 1);
+       cfqg->ref = 1;
 
        /*
         * Add group onto cgroup list. It might happen that bdi->dev is
@@ -1059,7 +1059,7 @@ static struct cfq_group *cfq_get_cfqg(struct cfq_data *cfqd, int create)
 
 static inline struct cfq_group *cfq_ref_get_cfqg(struct cfq_group *cfqg)
 {
-       atomic_inc(&cfqg->ref);
+       cfqg->ref++;
        return cfqg;
 }
 
@@ -1071,7 +1071,7 @@ static void cfq_link_cfqq_cfqg(struct cfq_queue *cfqq, struct cfq_group *cfqg)
 
        cfqq->cfqg = cfqg;
        /* cfqq reference on cfqg */
-       atomic_inc(&cfqq->cfqg->ref);
+       cfqq->cfqg->ref++;
 }
 
 static void cfq_put_cfqg(struct cfq_group *cfqg)
@@ -1079,8 +1079,9 @@ static void cfq_put_cfqg(struct cfq_group *cfqg)
        struct cfq_rb_root *st;
        int i, j;
 
-       BUG_ON(atomic_read(&cfqg->ref) <= 0);
-       if (!atomic_dec_and_test(&cfqg->ref))
+       BUG_ON(cfqg->ref <= 0);
+       cfqg->ref--;
+       if (cfqg->ref)
                return;
        for_each_cfqg_st(cfqg, i, j, st)
                BUG_ON(!RB_EMPTY_ROOT(&st->rb));
@@ -1188,7 +1189,7 @@ static void cfq_service_tree_add(struct cfq_data *cfqd, struct cfq_queue *cfqq,
                        cfq_group_service_tree_del(cfqd, cfqq->cfqg);
                cfqq->orig_cfqg = cfqq->cfqg;
                cfqq->cfqg = &cfqd->root_group;
-               atomic_inc(&cfqd->root_group.ref);
+               cfqd->root_group.ref++;
                group_changed = 1;
        } else if (!cfqd->cfq_group_isolation
                   && cfqq_type(cfqq) == SYNC_WORKLOAD && cfqq->orig_cfqg) {
@@ -2025,7 +2026,7 @@ static int cfqq_process_refs(struct cfq_queue *cfqq)
        int process_refs, io_refs;
 
        io_refs = cfqq->allocated[READ] + cfqq->allocated[WRITE];
-       process_refs = atomic_read(&cfqq->ref) - io_refs;
+       process_refs = cfqq->ref - io_refs;
        BUG_ON(process_refs < 0);
        return process_refs;
 }
@@ -2065,10 +2066,10 @@ static void cfq_setup_merge(struct cfq_queue *cfqq, struct cfq_queue *new_cfqq)
         */
        if (new_process_refs >= process_refs) {
                cfqq->new_cfqq = new_cfqq;
-               atomic_add(process_refs, &new_cfqq->ref);
+               new_cfqq->ref += process_refs;
        } else {
                new_cfqq->new_cfqq = cfqq;
-               atomic_add(new_process_refs, &cfqq->ref);
+               cfqq->ref += new_process_refs;
        }
 }
 
@@ -2103,12 +2104,6 @@ static void choose_service_tree(struct cfq_data *cfqd, struct cfq_group *cfqg)
        unsigned group_slice;
        enum wl_prio_t original_prio = cfqd->serving_prio;
 
-       if (!cfqg) {
-               cfqd->serving_prio = IDLE_WORKLOAD;
-               cfqd->workload_expires = jiffies + 1;
-               return;
-       }
-
        /* Choose next priority. RT > BE > IDLE */
        if (cfq_group_busy_queues_wl(RT_WORKLOAD, cfqd, cfqg))
                cfqd->serving_prio = RT_WORKLOAD;
@@ -2538,9 +2533,10 @@ static void cfq_put_queue(struct cfq_queue *cfqq)
        struct cfq_data *cfqd = cfqq->cfqd;
        struct cfq_group *cfqg, *orig_cfqg;
 
-       BUG_ON(atomic_read(&cfqq->ref) <= 0);
+       BUG_ON(cfqq->ref <= 0);
 
-       if (!atomic_dec_and_test(&cfqq->ref))
+       cfqq->ref--;
+       if (cfqq->ref)
                return;
 
        cfq_log_cfqq(cfqd, cfqq, "put_queue");
@@ -2843,7 +2839,7 @@ static void cfq_init_cfqq(struct cfq_data *cfqd, struct cfq_queue *cfqq,
        RB_CLEAR_NODE(&cfqq->p_node);
        INIT_LIST_HEAD(&cfqq->fifo);
 
-       atomic_set(&cfqq->ref, 0);
+       cfqq->ref = 0;
        cfqq->cfqd = cfqd;
 
        cfq_mark_cfqq_prio_changed(cfqq);
@@ -2979,11 +2975,11 @@ cfq_get_queue(struct cfq_data *cfqd, bool is_sync, struct io_context *ioc,
         * pin the queue now that it's allocated, scheduler exit will prune it
         */
        if (!is_sync && !(*async_cfqq)) {
-               atomic_inc(&cfqq->ref);
+               cfqq->ref++;
                *async_cfqq = cfqq;
        }
 
-       atomic_inc(&cfqq->ref);
+       cfqq->ref++;
        return cfqq;
 }
 
@@ -3685,13 +3681,13 @@ new_queue:
        }
 
        cfqq->allocated[rw]++;
-       atomic_inc(&cfqq->ref);
-
-       spin_unlock_irqrestore(q->queue_lock, flags);
-
+       cfqq->ref++;
        rq->elevator_private = cic;
        rq->elevator_private2 = cfqq;
        rq->elevator_private3 = cfq_ref_get_cfqg(cfqq->cfqg);
+
+       spin_unlock_irqrestore(q->queue_lock, flags);
+
        return 0;
 
 queue_fail:
@@ -3866,6 +3862,10 @@ static void *cfq_init_queue(struct request_queue *q)
        if (!cfqd)
                return NULL;
 
+       /*
+        * Don't need take queue_lock in the routine, since we are
+        * initializing the ioscheduler, and nobody is using cfqd
+        */
        cfqd->cic_index = i;
 
        /* Init root service tree */
@@ -3885,7 +3885,7 @@ static void *cfq_init_queue(struct request_queue *q)
         * Take a reference to root group which we never drop. This is just
         * to make sure that cfq_put_cfqg() does not try to kfree root group
         */
-       atomic_set(&cfqg->ref, 1);
+       cfqg->ref = 1;
        rcu_read_lock();
        cfq_blkiocg_add_blkio_group(&blkio_root_cgroup, &cfqg->blkg,
                                        (void *)cfqd, 0);
@@ -3905,7 +3905,7 @@ static void *cfq_init_queue(struct request_queue *q)
         * will not attempt to free it.
         */
        cfq_init_cfqq(cfqd, &cfqd->oom_cfqq, 1, 0);
-       atomic_inc(&cfqd->oom_cfqq.ref);
+       cfqd->oom_cfqq.ref++;
        cfq_link_cfqq_cfqg(&cfqd->oom_cfqq, &cfqd->root_group);
 
        INIT_LIST_HEAD(&cfqd->cic_list);