1 files changed, 117 insertions, 51 deletions

diff --git a/block/cfq-iosched.c b/block/cfq-iosched.c
index ed897b5ef31..7982b830db5 100644
--- a/block/cfq-iosched.c
+++ b/block/cfq-iosched.c
@@ -14,7 +14,7 @@
 #include <linux/rbtree.h>
 #include <linux/ioprio.h>
 #include <linux/blktrace_api.h>
-#include "blk-cgroup.h"
+#include "cfq.h"
 
 /*
  * tunables
@@ -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).
@@ -857,7 +879,7 @@ cfq_group_service_tree_del(struct cfq_data *cfqd, struct cfq_group *cfqg)
 	if (!RB_EMPTY_NODE(&cfqg->rb_node))
 		cfq_rb_erase(&cfqg->rb_node, st);
 	cfqg->saved_workload_slice = 0;
-	blkiocg_update_dequeue_stats(&cfqg->blkg, 1);
+	cfq_blkiocg_update_dequeue_stats(&cfqg->blkg, 1);
 }
 
 static inline unsigned int cfq_cfqq_slice_usage(struct cfq_queue *cfqq)
@@ -917,8 +939,8 @@ static void cfq_group_served(struct cfq_data *cfqd, struct cfq_group *cfqg,
 
 	cfq_log_cfqg(cfqd, cfqg, "served: vt=%llu min_vt=%llu", cfqg->vdisktime,
 					st->min_vdisktime);
-	blkiocg_update_timeslice_used(&cfqg->blkg, used_sl);
-	blkiocg_set_start_empty_time(&cfqg->blkg);
+	cfq_blkiocg_update_timeslice_used(&cfqg->blkg, used_sl);
+	cfq_blkiocg_set_start_empty_time(&cfqg->blkg);
 }
 
 #ifdef CONFIG_CFQ_GROUP_IOSCHED
@@ -973,7 +995,7 @@ cfq_find_alloc_cfqg(struct cfq_data *cfqd, struct cgroup *cgroup, int create)
 
 	/* Add group onto cgroup list */
 	sscanf(dev_name(bdi->dev), "%u:%u", &major, &minor);
-	blkiocg_add_blkio_group(blkcg, &cfqg->blkg, (void *)cfqd,
+	cfq_blkiocg_add_blkio_group(blkcg, &cfqg->blkg, (void *)cfqd,
 					MKDEV(major, minor));
 	cfqg->weight = blkcg_get_weight(blkcg, cfqg->blkg.dev);
 
@@ -1057,7 +1079,7 @@ static void cfq_release_cfq_groups(struct cfq_data *cfqd)
 		 * it from cgroup list, then it will take care of destroying
 		 * cfqg also.
 		 */
-		if (!blkiocg_del_blkio_group(&cfqg->blkg))
+		if (!cfq_blkiocg_del_blkio_group(&cfqg->blkg))
 			cfq_destroy_cfqg(cfqd, cfqg);
 	}
 }
@@ -1399,10 +1421,10 @@ static void cfq_reposition_rq_rb(struct cfq_queue *cfqq, struct request *rq)
 {
 	elv_rb_del(&cfqq->sort_list, rq);
 	cfqq->queued[rq_is_sync(rq)]--;
-	blkiocg_update_io_remove_stats(&(RQ_CFQG(rq))->blkg, rq_data_dir(rq),
-						rq_is_sync(rq));
+	cfq_blkiocg_update_io_remove_stats(&(RQ_CFQG(rq))->blkg,
+					rq_data_dir(rq), rq_is_sync(rq));
 	cfq_add_rq_rb(rq);
-	blkiocg_update_io_add_stats(&(RQ_CFQG(rq))->blkg,
+	cfq_blkiocg_update_io_add_stats(&(RQ_CFQG(rq))->blkg,
 			&cfqq->cfqd->serving_group->blkg, rq_data_dir(rq),
 			rq_is_sync(rq));
 }
@@ -1460,8 +1482,8 @@ static void cfq_remove_request(struct request *rq)
 	cfq_del_rq_rb(rq);
 
 	cfqq->cfqd->rq_queued--;
-	blkiocg_update_io_remove_stats(&(RQ_CFQG(rq))->blkg, rq_data_dir(rq),
-						rq_is_sync(rq));
+	cfq_blkiocg_update_io_remove_stats(&(RQ_CFQG(rq))->blkg,
+					rq_data_dir(rq), rq_is_sync(rq));
 	if (rq_is_meta(rq)) {
 		WARN_ON(!cfqq->meta_pending);
 		cfqq->meta_pending--;
@@ -1496,8 +1518,8 @@ static void cfq_merged_request(struct request_queue *q, struct request *req,
 static void cfq_bio_merged(struct request_queue *q, struct request *req,
 				struct bio *bio)
 {
-	blkiocg_update_io_merged_stats(&(RQ_CFQG(req))->blkg, bio_data_dir(bio),
-					cfq_bio_sync(bio));
+	cfq_blkiocg_update_io_merged_stats(&(RQ_CFQG(req))->blkg,
+					bio_data_dir(bio), cfq_bio_sync(bio));
 }
 
 static void
@@ -1517,8 +1539,8 @@ cfq_merged_requests(struct request_queue *q, struct request *rq,
 	if (cfqq->next_rq == next)
 		cfqq->next_rq = rq;
 	cfq_remove_request(next);
-	blkiocg_update_io_merged_stats(&(RQ_CFQG(rq))->blkg, rq_data_dir(next),
-					rq_is_sync(next));
+	cfq_blkiocg_update_io_merged_stats(&(RQ_CFQG(rq))->blkg,
+					rq_data_dir(next), rq_is_sync(next));
 }
 
 static int cfq_allow_merge(struct request_queue *q, struct request *rq,
@@ -1549,7 +1571,7 @@ static int cfq_allow_merge(struct request_queue *q, struct request *rq,
 static inline void cfq_del_timer(struct cfq_data *cfqd, struct cfq_queue *cfqq)
 {
 	del_timer(&cfqd->idle_slice_timer);
-	blkiocg_update_idle_time_stats(&cfqq->cfqg->blkg);
+	cfq_blkiocg_update_idle_time_stats(&cfqq->cfqg->blkg);
 }
 
 static void __cfq_set_active_queue(struct cfq_data *cfqd,
@@ -1558,7 +1580,7 @@ static void __cfq_set_active_queue(struct cfq_data *cfqd,
 	if (cfqq) {
 		cfq_log_cfqq(cfqd, cfqq, "set_active wl_prio:%d wl_type:%d",
 				cfqd->serving_prio, cfqd->serving_type);
-		blkiocg_update_avg_queue_size_stats(&cfqq->cfqg->blkg);
+		cfq_blkiocg_update_avg_queue_size_stats(&cfqq->cfqg->blkg);
 		cfqq->slice_start = 0;
 		cfqq->dispatch_start = jiffies;
 		cfqq->allocated_slice = 0;
@@ -1889,7 +1911,7 @@ static void cfq_arm_slice_timer(struct cfq_data *cfqd)
 	sl = cfqd->cfq_slice_idle;
 
 	mod_timer(&cfqd->idle_slice_timer, jiffies + sl);
-	blkiocg_update_set_idle_time_stats(&cfqq->cfqg->blkg);
+	cfq_blkiocg_update_set_idle_time_stats(&cfqq->cfqg->blkg);
 	cfq_log_cfqq(cfqd, cfqq, "arm_idle: %lu", sl);
 }
 
@@ -1909,7 +1931,7 @@ static void cfq_dispatch_insert(struct request_queue *q, struct request *rq)
 	elv_dispatch_sort(q, rq);
 
 	cfqd->rq_in_flight[cfq_cfqq_sync(cfqq)]++;
-	blkiocg_update_dispatch_stats(&cfqq->cfqg->blkg, blk_rq_bytes(rq),
+	cfq_blkiocg_update_dispatch_stats(&cfqq->cfqg->blkg, blk_rq_bytes(rq),
 					rq_data_dir(rq), rq_is_sync(rq));
 }
 
@@ -1964,6 +1986,15 @@ static void cfq_setup_merge(struct cfq_queue *cfqq, struct cfq_queue *new_cfqq)
 	int process_refs, new_process_refs;
 	struct cfq_queue *__cfqq;
 
+	/*
+	 * If there are no process references on the new_cfqq, then it is
+	 * unsafe to follow the ->new_cfqq chain as other cfqq's in the
+	 * chain may have dropped their last reference (not just their
+	 * last process reference).
+	 */
+	if (!cfqq_process_refs(new_cfqq))
+		return;
+
 	/* Avoid a circular list and skip interim queue merges */
 	while ((__cfqq = new_cfqq->new_cfqq)) {
 		if (__cfqq == cfqq)
@@ -1972,17 +2003,17 @@ static void cfq_setup_merge(struct cfq_queue *cfqq, struct cfq_queue *new_cfqq)
 	}
 
 	process_refs = cfqq_process_refs(cfqq);
+	new_process_refs = cfqq_process_refs(new_cfqq);
 	/*
 	 * If the process for the cfqq has gone away, there is no
 	 * sense in merging the queues.
 	 */
-	if (process_refs == 0)
+	if (process_refs == 0 || new_process_refs == 0)
 		return;
 
 	/*
 	 * Merge in the direction of the lesser amount of work.
 	 */
-	new_process_refs = cfqq_process_refs(new_cfqq);
 	if (new_process_refs >= process_refs) {
 		cfqq->new_cfqq = new_cfqq;
 		atomic_add(process_refs, &new_cfqq->ref);
@@ -2510,11 +2541,12 @@ 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 +2569,10 @@ 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 +2588,16 @@ 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 +2610,10 @@ 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 +2632,7 @@ 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 +2645,7 @@ 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 +2725,7 @@ 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 +2782,7 @@ 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 +2919,13 @@ 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 +2937,6 @@ 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 +2953,11 @@ 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 +2990,7 @@ 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);
@@ -3223,7 +3257,7 @@ cfq_rq_enqueued(struct cfq_data *cfqd, struct cfq_queue *cfqq,
 				cfq_clear_cfqq_wait_request(cfqq);
 				__blk_run_queue(cfqd->queue);
 			} else {
-				blkiocg_update_idle_time_stats(
+				cfq_blkiocg_update_idle_time_stats(
 						&cfqq->cfqg->blkg);
 				cfq_mark_cfqq_must_dispatch(cfqq);
 			}
@@ -3251,7 +3285,7 @@ static void cfq_insert_request(struct request_queue *q, struct request *rq)
 	rq_set_fifo_time(rq, jiffies + cfqd->cfq_fifo_expire[rq_is_sync(rq)]);
 	list_add_tail(&rq->queuelist, &cfqq->fifo);
 	cfq_add_rq_rb(rq);
-	blkiocg_update_io_add_stats(&(RQ_CFQG(rq))->blkg,
+	cfq_blkiocg_update_io_add_stats(&(RQ_CFQG(rq))->blkg,
 			&cfqd->serving_group->blkg, rq_data_dir(rq),
 			rq_is_sync(rq));
 	cfq_rq_enqueued(cfqd, cfqq, rq);
@@ -3339,9 +3373,9 @@ static void cfq_completed_request(struct request_queue *q, struct request *rq)
 	WARN_ON(!cfqq->dispatched);
 	cfqd->rq_in_driver--;
 	cfqq->dispatched--;
-	blkiocg_update_completion_stats(&cfqq->cfqg->blkg, rq_start_time_ns(rq),
-			rq_io_start_time_ns(rq), rq_data_dir(rq),
-			rq_is_sync(rq));
+	cfq_blkiocg_update_completion_stats(&cfqq->cfqg->blkg,
+			rq_start_time_ns(rq), rq_io_start_time_ns(rq),
+			rq_data_dir(rq), rq_is_sync(rq));
 
 	cfqd->rq_in_flight[cfq_cfqq_sync(cfqq)]--;
 
@@ -3516,6 +3550,9 @@ 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;
 }
@@ -3702,16 +3739,38 @@ static void cfq_exit_queue(struct elevator_queue *e)
 
 	cfq_put_async_queues(cfqd);
 	cfq_release_cfq_groups(cfqd);
-	blkiocg_del_blkio_group(&cfqd->root_group.blkg);
+	cfq_blkiocg_del_blkio_group(&cfqd->root_group.blkg);
 
 	spin_unlock_irq(q->queue_lock);
 
 	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 +3778,16 @@ 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;
 
@@ -3742,8 +3807,8 @@ static void *cfq_init_queue(struct request_queue *q)
 	 */
 	atomic_set(&cfqg->ref, 1);
 	rcu_read_lock();
-	blkiocg_add_blkio_group(&blkio_root_cgroup, &cfqg->blkg, (void *)cfqd,
-					0);
+	cfq_blkiocg_add_blkio_group(&blkio_root_cgroup, &cfqg->blkg,
+					(void *)cfqd, 0);
 	rcu_read_unlock();
 #endif
 	/*
@@ -3984,6 +4049,7 @@ 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();
 }