pandora: update defconfig
[pandora-kernel.git] / block / cfq-iosched.c
index ed897b5..5ff4f48 100644 (file)
@@ -64,6 +64,9 @@ static DEFINE_PER_CPU(unsigned long, cfq_ioc_count);
 static struct completion *ioc_gone;
 static DEFINE_SPINLOCK(ioc_gone_lock);
 
+static DEFINE_SPINLOCK(cic_index_lock);
+static DEFINE_IDA(cic_index_ida);
+
 #define CFQ_PRIO_LISTS         IOPRIO_BE_NR
 #define cfq_class_idle(cfqq)   ((cfqq)->ioprio_class == IOPRIO_CLASS_IDLE)
 #define cfq_class_rt(cfqq)     ((cfqq)->ioprio_class == IOPRIO_CLASS_RT)
@@ -271,6 +274,7 @@ struct cfq_data {
        unsigned int cfq_latency;
        unsigned int cfq_group_isolation;
 
+       unsigned int cic_index;
        struct list_head cic_list;
 
        /*
@@ -430,6 +434,24 @@ static inline void cic_set_cfqq(struct cfq_io_context *cic,
        cic->cfqq[is_sync] = cfqq;
 }
 
+#define CIC_DEAD_KEY   1ul
+#define CIC_DEAD_INDEX_SHIFT   1
+
+static inline void *cfqd_dead_key(struct cfq_data *cfqd)
+{
+       return (void *)(cfqd->cic_index << CIC_DEAD_INDEX_SHIFT | CIC_DEAD_KEY);
+}
+
+static inline struct cfq_data *cic_to_cfqd(struct cfq_io_context *cic)
+{
+       struct cfq_data *cfqd = cic->key;
+
+       if (unlikely((unsigned long) cfqd & CIC_DEAD_KEY))
+               return NULL;
+
+       return cfqd;
+}
+
 /*
  * We regard a request as SYNC, if it's either a read or has the SYNC bit
  * set (in which case it could also be direct WRITE).
@@ -2510,11 +2532,12 @@ static void cfq_cic_free(struct cfq_io_context *cic)
 static void cic_free_func(struct io_context *ioc, struct cfq_io_context *cic)
 {
        unsigned long flags;
+       unsigned long dead_key = (unsigned long) cic->key;
 
-       BUG_ON(!cic->dead_key);
+       BUG_ON(!(dead_key & CIC_DEAD_KEY));
 
        spin_lock_irqsave(&ioc->lock, flags);
-       radix_tree_delete(&ioc->radix_root, cic->dead_key);
+       radix_tree_delete(&ioc->radix_root, dead_key >> CIC_DEAD_INDEX_SHIFT);
        hlist_del_rcu(&cic->cic_list);
        spin_unlock_irqrestore(&ioc->lock, flags);
 
@@ -2537,15 +2560,10 @@ static void cfq_free_io_context(struct io_context *ioc)
        __call_for_each_cic(ioc, cic_free_func);
 }
 
-static void cfq_exit_cfqq(struct cfq_data *cfqd, struct cfq_queue *cfqq)
+static void cfq_put_cooperator(struct cfq_queue *cfqq)
 {
        struct cfq_queue *__cfqq, *next;
 
-       if (unlikely(cfqq == cfqd->active_queue)) {
-               __cfq_slice_expired(cfqd, cfqq, 0);
-               cfq_schedule_dispatch(cfqd);
-       }
-
        /*
         * If this queue was scheduled to merge with another queue, be
         * sure to drop the reference taken on that queue (and others in
@@ -2561,6 +2579,16 @@ static void cfq_exit_cfqq(struct cfq_data *cfqd, struct cfq_queue *cfqq)
                cfq_put_queue(__cfqq);
                __cfqq = next;
        }
+}
+
+static void cfq_exit_cfqq(struct cfq_data *cfqd, struct cfq_queue *cfqq)
+{
+       if (unlikely(cfqq == cfqd->active_queue)) {
+               __cfq_slice_expired(cfqd, cfqq, 0);
+               cfq_schedule_dispatch(cfqd);
+       }
+
+       cfq_put_cooperator(cfqq);
 
        cfq_put_queue(cfqq);
 }
@@ -2573,11 +2601,10 @@ static void __cfq_exit_single_io_context(struct cfq_data *cfqd,
        list_del_init(&cic->queue_list);
 
        /*
-        * Make sure key == NULL is seen for dead queues
+        * Make sure dead mark is seen for dead queues
         */
        smp_wmb();
-       cic->dead_key = (unsigned long) cic->key;
-       cic->key = NULL;
+       cic->key = cfqd_dead_key(cfqd);
 
        if (ioc->ioc_data == cic)
                rcu_assign_pointer(ioc->ioc_data, NULL);
@@ -2596,7 +2623,7 @@ static void __cfq_exit_single_io_context(struct cfq_data *cfqd,
 static void cfq_exit_single_io_context(struct io_context *ioc,
                                       struct cfq_io_context *cic)
 {
-       struct cfq_data *cfqd = cic->key;
+       struct cfq_data *cfqd = cic_to_cfqd(cic);
 
        if (cfqd) {
                struct request_queue *q = cfqd->queue;
@@ -2609,7 +2636,7 @@ static void cfq_exit_single_io_context(struct io_context *ioc,
                 * race between exiting task and queue
                 */
                smp_read_barrier_depends();
-               if (cic->key)
+               if (cic->key == cfqd)
                        __cfq_exit_single_io_context(cfqd, cic);
 
                spin_unlock_irqrestore(q->queue_lock, flags);
@@ -2689,7 +2716,7 @@ static void cfq_init_prio_data(struct cfq_queue *cfqq, struct io_context *ioc)
 
 static void changed_ioprio(struct io_context *ioc, struct cfq_io_context *cic)
 {
-       struct cfq_data *cfqd = cic->key;
+       struct cfq_data *cfqd = cic_to_cfqd(cic);
        struct cfq_queue *cfqq;
        unsigned long flags;
 
@@ -2746,7 +2773,7 @@ static void cfq_init_cfqq(struct cfq_data *cfqd, struct cfq_queue *cfqq,
 static void changed_cgroup(struct io_context *ioc, struct cfq_io_context *cic)
 {
        struct cfq_queue *sync_cfqq = cic_to_cfqq(cic, 1);
-       struct cfq_data *cfqd = cic->key;
+       struct cfq_data *cfqd = cic_to_cfqd(cic);
        unsigned long flags;
        struct request_queue *q;
 
@@ -2883,12 +2910,13 @@ cfq_drop_dead_cic(struct cfq_data *cfqd, struct io_context *ioc,
        unsigned long flags;
 
        WARN_ON(!list_empty(&cic->queue_list));
+       BUG_ON(cic->key != cfqd_dead_key(cfqd));
 
        spin_lock_irqsave(&ioc->lock, flags);
 
        BUG_ON(ioc->ioc_data == cic);
 
-       radix_tree_delete(&ioc->radix_root, (unsigned long) cfqd);
+       radix_tree_delete(&ioc->radix_root, cfqd->cic_index);
        hlist_del_rcu(&cic->cic_list);
        spin_unlock_irqrestore(&ioc->lock, flags);
 
@@ -2900,7 +2928,6 @@ cfq_cic_lookup(struct cfq_data *cfqd, struct io_context *ioc)
 {
        struct cfq_io_context *cic;
        unsigned long flags;
-       void *k;
 
        if (unlikely(!ioc))
                return NULL;
@@ -2917,13 +2944,11 @@ cfq_cic_lookup(struct cfq_data *cfqd, struct io_context *ioc)
        }
 
        do {
-               cic = radix_tree_lookup(&ioc->radix_root, (unsigned long) cfqd);
+               cic = radix_tree_lookup(&ioc->radix_root, cfqd->cic_index);
                rcu_read_unlock();
                if (!cic)
                        break;
-               /* ->key must be copied to avoid race with cfq_exit_queue() */
-               k = cic->key;
-               if (unlikely(!k)) {
+               if (unlikely(cic->key != cfqd)) {
                        cfq_drop_dead_cic(cfqd, ioc, cic);
                        rcu_read_lock();
                        continue;
@@ -2956,7 +2981,7 @@ static int cfq_cic_link(struct cfq_data *cfqd, struct io_context *ioc,
 
                spin_lock_irqsave(&ioc->lock, flags);
                ret = radix_tree_insert(&ioc->radix_root,
-                                               (unsigned long) cfqd, cic);
+                                               cfqd->cic_index, cic);
                if (!ret)
                        hlist_add_head_rcu(&cic->cic_list, &ioc->cic_list);
                spin_unlock_irqrestore(&ioc->lock, flags);
@@ -3516,6 +3541,9 @@ split_cfqq(struct cfq_io_context *cic, struct cfq_queue *cfqq)
        }
 
        cic_set_cfqq(cic, NULL, 1);
+
+       cfq_put_cooperator(cfqq);
+
        cfq_put_queue(cfqq);
        return NULL;
 }
@@ -3708,10 +3736,32 @@ static void cfq_exit_queue(struct elevator_queue *e)
 
        cfq_shutdown_timer_wq(cfqd);
 
+       spin_lock(&cic_index_lock);
+       ida_remove(&cic_index_ida, cfqd->cic_index);
+       spin_unlock(&cic_index_lock);
+
        /* Wait for cfqg->blkg->key accessors to exit their grace periods. */
        call_rcu(&cfqd->rcu, cfq_cfqd_free);
 }
 
+static int cfq_alloc_cic_index(void)
+{
+       int index, error;
+
+       do {
+               if (!ida_pre_get(&cic_index_ida, GFP_KERNEL))
+                       return -ENOMEM;
+
+               spin_lock(&cic_index_lock);
+               error = ida_get_new(&cic_index_ida, &index);
+               spin_unlock(&cic_index_lock);
+               if (error && error != -EAGAIN)
+                       return error;
+       } while (error);
+
+       return index;
+}
+
 static void *cfq_init_queue(struct request_queue *q)
 {
        struct cfq_data *cfqd;
@@ -3719,10 +3769,16 @@ static void *cfq_init_queue(struct request_queue *q)
        struct cfq_group *cfqg;
        struct cfq_rb_root *st;
 
+       i = cfq_alloc_cic_index();
+       if (i < 0)
+               return NULL;
+
        cfqd = kmalloc_node(sizeof(*cfqd), GFP_KERNEL | __GFP_ZERO, q->node);
        if (!cfqd)
                return NULL;
 
+       cfqd->cic_index = i;
+
        /* Init root service tree */
        cfqd->grp_service_tree = CFQ_RB_ROOT;
 
@@ -3984,6 +4040,7 @@ static void __exit cfq_exit(void)
         */
        if (elv_ioc_count_read(cfq_ioc_count))
                wait_for_completion(&all_gone);
+       ida_destroy(&cic_index_ida);
        cfq_slab_kill();
 }