Merge commit 'v2.6.38-rc6' into for-2.6.39/core

Conflicts:
	block/cfq-iosched.c

Signed-off-by: Jens Axboe <jaxboe@fusionio.com>

block/Kconfig

@@ -2,7 +2,7 @@
 # Block layer core configuration
 #
 menuconfig BLOCK
-       bool "Enable the block layer" if EMBEDDED
+       bool "Enable the block layer" if EXPERT
        default y
        help
 	 Provide block layer support for the kernel.

block/blk-cgroup.c

@@ -1452,10 +1452,6 @@ blkiocg_create(struct cgroup_subsys *subsys, struct cgroup *cgroup)
 		goto done;
 	}
 
-	/* Currently we do not support hierarchy deeper than two level (0,1) */
-	if (parent != cgroup->top_cgroup)
-		return ERR_PTR(-EPERM);
-
 	blkcg = kzalloc(sizeof(*blkcg), GFP_KERNEL);
 	if (!blkcg)
 		return ERR_PTR(-ENOMEM);

block/blk-core.c

@@ -33,7 +33,7 @@
 
 #include "blk.h"
 
-EXPORT_TRACEPOINT_SYMBOL_GPL(block_remap);
+EXPORT_TRACEPOINT_SYMBOL_GPL(block_bio_remap);
 EXPORT_TRACEPOINT_SYMBOL_GPL(block_rq_remap);
 EXPORT_TRACEPOINT_SYMBOL_GPL(block_bio_complete);
 
@@ -64,13 +64,27 @@ static void drive_stat_acct(struct request *rq, int new_io)
 		return;
 
 	cpu = part_stat_lock();
-	part = disk_map_sector_rcu(rq->rq_disk, blk_rq_pos(rq));
 
-	if (!new_io)
+	if (!new_io) {
+		part = rq->part;
 		part_stat_inc(cpu, part, merges[rw]);
-	else {
+	} else {
+		part = disk_map_sector_rcu(rq->rq_disk, blk_rq_pos(rq));
+		if (!hd_struct_try_get(part)) {
+			/*
+			 * The partition is already being removed,
+			 * the request will be accounted on the disk only
+			 *
+			 * We take a reference on disk->part0 although that
+			 * partition will never be deleted, so we can treat
+			 * it as any other partition.
+			 */
+			part = &rq->rq_disk->part0;
+			hd_struct_get(part);
+		}
 		part_round_stats(cpu, part);
 		part_inc_in_flight(part, rw);
+		rq->part = part;
 	}
 
 	part_stat_unlock();
@@ -128,6 +142,7 @@ void blk_rq_init(struct request_queue *q, struct request *rq)
 	rq->ref_count = 1;
 	rq->start_time = jiffies;
 	set_start_time_ns(rq);
+	rq->part = NULL;
 }
 EXPORT_SYMBOL(blk_rq_init);
 
@@ -1342,9 +1357,9 @@ static inline void blk_partition_remap(struct bio *bio)
 		bio->bi_sector += p->start_sect;
 		bio->bi_bdev = bdev->bd_contains;
 
-		trace_block_remap(bdev_get_queue(bio->bi_bdev), bio,
-				    bdev->bd_dev,
-				    bio->bi_sector - p->start_sect);
+		trace_block_bio_remap(bdev_get_queue(bio->bi_bdev), bio,
+				      bdev->bd_dev,
+				      bio->bi_sector - p->start_sect);
 	}
 }
 
@@ -1513,7 +1528,7 @@ static inline void __generic_make_request(struct bio *bio)
 			goto end_io;
 
 		if (old_sector != -1)
-			trace_block_remap(q, bio, old_dev, old_sector);
+			trace_block_bio_remap(q, bio, old_dev, old_sector);
 
 		old_sector = bio->bi_sector;
 		old_dev = bio->bi_bdev->bd_dev;
@@ -1789,7 +1804,7 @@ static void blk_account_io_completion(struct request *req, unsigned int bytes)
 		int cpu;
 
 		cpu = part_stat_lock();
-		part = disk_map_sector_rcu(req->rq_disk, blk_rq_pos(req));
+		part = req->part;
 		part_stat_add(cpu, part, sectors[rw], bytes >> 9);
 		part_stat_unlock();
 	}
@@ -1809,13 +1824,14 @@ static void blk_account_io_done(struct request *req)
 		int cpu;
 
 		cpu = part_stat_lock();
-		part = disk_map_sector_rcu(req->rq_disk, blk_rq_pos(req));
+		part = req->part;
 
 		part_stat_inc(cpu, part, ios[rw]);
 		part_stat_add(cpu, part, ticks[rw], duration);
 		part_round_stats(cpu, part);
 		part_dec_in_flight(part, rw);
 
+		hd_struct_put(part);
 		part_stat_unlock();
 	}
 }
@@ -2619,7 +2635,9 @@ int __init blk_dev_init(void)
 	BUILD_BUG_ON(__REQ_NR_BITS > 8 *
 			sizeof(((struct request *)0)->cmd_flags));
 
-	kblockd_workqueue = create_workqueue("kblockd");
+	/* used for unplugging and affects IO latency/throughput - HIGHPRI */
+	kblockd_workqueue = alloc_workqueue("kblockd",
+					    WQ_MEM_RECLAIM | WQ_HIGHPRI, 0);
 	if (!kblockd_workqueue)
 		panic("Failed to create kblockd\n");
 

block/blk-ioc.c

@@ -64,7 +64,7 @@ static void cfq_exit(struct io_context *ioc)
 	rcu_read_unlock();
 }
 
-/* Called by the exitting task */
+/* Called by the exiting task */
 void exit_io_context(struct task_struct *task)
 {
 	struct io_context *ioc;
@@ -74,10 +74,9 @@ void exit_io_context(struct task_struct *task)
 	task->io_context = NULL;
 	task_unlock(task);
 
-	if (atomic_dec_and_test(&ioc->nr_tasks)) {
+	if (atomic_dec_and_test(&ioc->nr_tasks))
 		cfq_exit(ioc);
 
-	}
 	put_io_context(ioc);
 }
 

block/blk-merge.c

@@ -351,11 +351,12 @@ static void blk_account_io_merge(struct request *req)
 		int cpu;
 
 		cpu = part_stat_lock();
-		part = disk_map_sector_rcu(req->rq_disk, blk_rq_pos(req));
+		part = req->part;
 
 		part_round_stats(cpu, part);
 		part_dec_in_flight(part, rq_data_dir(req));
 
+		hd_struct_put(part);
 		part_stat_unlock();
 	}
 }

block/blk-throttle.c

@@ -168,7 +168,15 @@ static struct throtl_grp * throtl_find_alloc_tg(struct throtl_data *td,
 	 * tree of blkg (instead of traversing through hash list all
 	 * the time.
 	 */
-	tg = tg_of_blkg(blkiocg_lookup_group(blkcg, key));
+
+	/*
+	 * This is the common case when there are no blkio cgroups.
+ 	 * Avoid lookup in this case
+ 	 */
+	if (blkcg == &blkio_root_cgroup)
+		tg = &td->root_tg;
+	else
+		tg = tg_of_blkg(blkiocg_lookup_group(blkcg, key));
 
 	/* Fill in device details for root group */
 	if (tg && !tg->blkg.dev && bdi->dev && dev_name(bdi->dev)) {

block/cfq-iosched.c

@@ -87,7 +87,6 @@ struct cfq_rb_root {
 	unsigned count;
 	unsigned total_weight;
 	u64 min_vdisktime;
-	struct rb_node *active;
 };
 #define CFQ_RB_ROOT	(struct cfq_rb_root) { .rb = RB_ROOT, .left = NULL, \
 			.count = 0, .min_vdisktime = 0, }
@@ -97,7 +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 */
@@ -180,7 +179,6 @@ struct cfq_group {
 	/* group service_tree key */
 	u64 vdisktime;
 	unsigned int weight;
-	bool on_st;
 
 	/* number of cfqq currently on this group */
 	int nr_cfqq;
@@ -209,7 +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;
@@ -563,11 +561,6 @@ static void update_min_vdisktime(struct cfq_rb_root *st)
 	u64 vdisktime = st->min_vdisktime;
 	struct cfq_group *cfqg;
 
-	if (st->active) {
-		cfqg = rb_entry_cfqg(st->active);
-		vdisktime = cfqg->vdisktime;
-	}
-
 	if (st->left) {
 		cfqg = rb_entry_cfqg(st->left);
 		vdisktime = min_vdisktime(vdisktime, cfqg->vdisktime);
@@ -605,8 +598,8 @@ cfq_group_slice(struct cfq_data *cfqd, struct cfq_group *cfqg)
 	return cfq_target_latency * cfqg->weight / st->total_weight;
 }
 
-static inline void
-cfq_set_prio_slice(struct cfq_data *cfqd, struct cfq_queue *cfqq)
+static inline unsigned
+cfq_scaled_cfqq_slice(struct cfq_data *cfqd, struct cfq_queue *cfqq)
 {
 	unsigned slice = cfq_prio_to_slice(cfqd, cfqq);
 	if (cfqd->cfq_latency) {
@@ -632,6 +625,14 @@ cfq_set_prio_slice(struct cfq_data *cfqd, struct cfq_queue *cfqq)
 				    low_slice);
 		}
 	}
+	return slice;
+}
+
+static inline void
+cfq_set_prio_slice(struct cfq_data *cfqd, struct cfq_queue *cfqq)
+{
+	unsigned slice = cfq_scaled_cfqq_slice(cfqd, cfqq);
+
 	cfqq->slice_start = jiffies;
 	cfqq->slice_end = jiffies + slice;
 	cfqq->allocated_slice = slice;
@@ -646,11 +647,11 @@ cfq_set_prio_slice(struct cfq_data *cfqd, struct cfq_queue *cfqq)
 static inline bool cfq_slice_used(struct cfq_queue *cfqq)
 {
 	if (cfq_cfqq_slice_new(cfqq))
-		return 0;
+		return false;
 	if (time_before(jiffies, cfqq->slice_end))
-		return 0;
+		return false;
 
-	return 1;
+	return true;
 }
 
 /*
@@ -869,7 +870,7 @@ cfq_group_service_tree_add(struct cfq_data *cfqd, struct cfq_group *cfqg)
 	struct rb_node *n;
 
 	cfqg->nr_cfqq++;
-	if (cfqg->on_st)
+	if (!RB_EMPTY_NODE(&cfqg->rb_node))
 		return;
 
 	/*
@@ -885,7 +886,6 @@ cfq_group_service_tree_add(struct cfq_data *cfqd, struct cfq_group *cfqg)
 		cfqg->vdisktime = st->min_vdisktime;
 
 	__cfq_group_service_tree_add(st, cfqg);
-	cfqg->on_st = true;
 	st->total_weight += cfqg->weight;
 }
 
@@ -894,9 +894,6 @@ cfq_group_service_tree_del(struct cfq_data *cfqd, struct cfq_group *cfqg)
 {
 	struct cfq_rb_root *st = &cfqd->grp_service_tree;
 
-	if (st->active == &cfqg->rb_node)
-		st->active = NULL;
-
 	BUG_ON(cfqg->nr_cfqq < 1);
 	cfqg->nr_cfqq--;
 
@@ -905,7 +902,6 @@ cfq_group_service_tree_del(struct cfq_data *cfqd, struct cfq_group *cfqg)
 		return;
 
 	cfq_log_cfqg(cfqd, cfqg, "del_from_rr group");
-	cfqg->on_st = false;
 	st->total_weight -= cfqg->weight;
 	if (!RB_EMPTY_NODE(&cfqg->rb_node))
 		cfq_rb_erase(&cfqg->rb_node, st);
@@ -1026,11 +1022,11 @@ 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
-	 * not initiliazed yet. Initialize this new group without major
+	 * not initialized yet. Initialize this new group without major
 	 * and minor info and this info will be filled in once a new thread
 	 * comes for IO. See code above.
 	 */
@@ -1071,7 +1067,7 @@ 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;
 }
 
@@ -1083,7 +1079,7 @@ 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)
@@ -1091,11 +1087,12 @@ 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) || st->active != NULL);
+		BUG_ON(!RB_EMPTY_ROOT(&st->rb));
 	kfree(cfqg);
 }
 
@@ -1200,7 +1197,7 @@ 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) {
@@ -1672,8 +1669,11 @@ __cfq_slice_expired(struct cfq_data *cfqd, struct cfq_queue *cfqq,
 	/*
 	 * store what was left of this slice, if the queue idled/timed out
 	 */
-	if (timed_out && !cfq_cfqq_slice_new(cfqq)) {
-		cfqq->slice_resid = cfqq->slice_end - jiffies;
+	if (timed_out) {
+		if (cfq_cfqq_slice_new(cfqq))
+			cfqq->slice_resid = cfq_scaled_cfqq_slice(cfqd, cfqq);
+		else
+			cfqq->slice_resid = cfqq->slice_end - jiffies;
 		cfq_log_cfqq(cfqd, cfqq, "resid=%ld", cfqq->slice_resid);
 	}
 
@@ -1687,9 +1687,6 @@ __cfq_slice_expired(struct cfq_data *cfqd, struct cfq_queue *cfqq,
 	if (cfqq == cfqd->active_queue)
 		cfqd->active_queue = NULL;
 
-	if (&cfqq->cfqg->rb_node == cfqd->grp_service_tree.active)
-		cfqd->grp_service_tree.active = NULL;
-
 	if (cfqd->active_cic) {
 		put_io_context(cfqd->active_cic->ioc);
 		cfqd->active_cic = NULL;
@@ -1901,10 +1898,10 @@ static bool cfq_should_idle(struct cfq_data *cfqd, struct cfq_queue *cfqq)
 	 * in their service tree.
 	 */
 	if (service_tree->count == 1 && cfq_cfqq_sync(cfqq))
-		return 1;
+		return true;
 	cfq_log_cfqq(cfqd, cfqq, "Not idling. st->count:%d",
 			service_tree->count);
-	return 0;
+	return false;
 }
 
 static void cfq_arm_slice_timer(struct cfq_data *cfqd)
@@ -2040,7 +2037,7 @@ 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;
 }
@@ -2080,10 +2077,10 @@ 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;
 	}
 }
 
@@ -2116,12 +2113,7 @@ static void choose_service_tree(struct cfq_data *cfqd, struct cfq_group *cfqg)
 	unsigned count;
 	struct cfq_rb_root *st;
 	unsigned group_slice;
-
-	if (!cfqg) {
-		cfqd->serving_prio = IDLE_WORKLOAD;
-		cfqd->workload_expires = jiffies + 1;
-		return;
-	}
+	enum wl_prio_t original_prio = cfqd->serving_prio;
 
 	/* Choose next priority. RT > BE > IDLE */
 	if (cfq_group_busy_queues_wl(RT_WORKLOAD, cfqd, cfqg))
@@ -2134,6 +2126,9 @@ static void choose_service_tree(struct cfq_data *cfqd, struct cfq_group *cfqg)
 		return;
 	}
 
+	if (original_prio != cfqd->serving_prio)
+		goto new_workload;
+
 	/*
 	 * For RT and BE, we have to choose also the type
 	 * (SYNC, SYNC_NOIDLE, ASYNC), and to compute a workload
@@ -2148,6 +2143,7 @@ static void choose_service_tree(struct cfq_data *cfqd, struct cfq_group *cfqg)
 	if (count && !time_after(jiffies, cfqd->workload_expires))
 		return;
 
+new_workload:
 	/* otherwise select new workload type */
 	cfqd->serving_type =
 		cfq_choose_wl(cfqd, cfqg, cfqd->serving_prio);
@@ -2199,7 +2195,6 @@ static struct cfq_group *cfq_get_next_cfqg(struct cfq_data *cfqd)
 	if (RB_EMPTY_ROOT(&st->rb))
 		return NULL;
 	cfqg = cfq_rb_first_group(st);
-	st->active = &cfqg->rb_node;
 	update_min_vdisktime(st);
 	return cfqg;
 }
@@ -2293,6 +2288,17 @@ static struct cfq_queue *cfq_select_queue(struct cfq_data *cfqd)
 		goto keep_queue;
 	}
 
+	/*
+	 * This is a deep seek queue, but the device is much faster than
+	 * the queue can deliver, don't idle
+	 **/
+	if (CFQQ_SEEKY(cfqq) && cfq_cfqq_idle_window(cfqq) &&
+	    (cfq_cfqq_slice_new(cfqq) ||
+	    (cfqq->slice_end - jiffies > jiffies - cfqq->slice_start))) {
+		cfq_clear_cfqq_deep(cfqq);
+		cfq_clear_cfqq_idle_window(cfqq);
+	}
+
 	if (cfqq->dispatched && cfq_should_idle(cfqd, cfqq)) {
 		cfqq = NULL;
 		goto keep_queue;
@@ -2367,12 +2373,12 @@ static inline bool cfq_slice_used_soon(struct cfq_data *cfqd,
 {
 	/* the queue hasn't finished any request, can't estimate */
 	if (cfq_cfqq_slice_new(cfqq))
-		return 1;
+		return true;
 	if (time_after(jiffies + cfqd->cfq_slice_idle * cfqq->dispatched,
 		cfqq->slice_end))
-		return 1;
+		return true;
 
-	return 0;
+	return false;
 }
 
 static bool cfq_may_dispatch(struct cfq_data *cfqd, struct cfq_queue *cfqq)
@@ -2538,9 +2544,10 @@ 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 +2850,7 @@ 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 +2986,11 @@ 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;
 }
 
@@ -3265,6 +3272,10 @@ cfq_should_preempt(struct cfq_data *cfqd, struct cfq_queue *new_cfqq,
 	if (cfq_class_rt(new_cfqq) && !cfq_class_rt(cfqq))
 		return true;
 
+	/* An idle queue should not be idle now for some reason */
+	if (RB_EMPTY_ROOT(&cfqq->sort_list) && !cfq_should_idle(cfqd, cfqq))
+		return true;
+
 	if (!cfqd->active_cic || !cfq_cfqq_wait_request(cfqq))
 		return false;
 
@@ -3284,9 +3295,18 @@ cfq_should_preempt(struct cfq_data *cfqd, struct cfq_queue *new_cfqq,
  */
 static void cfq_preempt_queue(struct cfq_data *cfqd, struct cfq_queue *cfqq)
 {
+	struct cfq_queue *old_cfqq = cfqd->active_queue;
+
 	cfq_log_cfqq(cfqd, cfqq, "preempt");
 	cfq_slice_expired(cfqd, 1);
 
+	/*
+	 * workload type is changed, don't save slice, otherwise preempt
+	 * doesn't happen
+	 */
+	if (cfqq_type(old_cfqq) != cfqq_type(cfqq))
+		cfqq->cfqg->saved_workload_slice = 0;
+
 	/*
 	 * Put the new queue at the front of the of the current list,
 	 * so we know that it will be selected next.
@@ -3412,6 +3432,10 @@ static bool cfq_should_wait_busy(struct cfq_data *cfqd, struct cfq_queue *cfqq)
 {
 	struct cfq_io_context *cic = cfqd->active_cic;
 
+	/* If the queue already has requests, don't wait */
+	if (!RB_EMPTY_ROOT(&cfqq->sort_list))
+		return false;
+
 	/* If there are other queues in the group, don't wait */
 	if (cfqq->cfqg->nr_cfqq > 1)
 		return false;
@@ -3681,10 +3705,10 @@ new_queue:
 	}
 
 	cfqq->allocated[rw]++;
-	atomic_inc(&cfqq->ref);
 
 	spin_unlock_irqrestore(q->queue_lock, flags);
 
+	cfqq->ref++;
 	rq->elevator_private[0] = cic;
 	rq->elevator_private[1] = cfqq;
 	rq->elevator_private[2] = cfq_ref_get_cfqg(cfqq->cfqg);
@@ -3862,6 +3886,10 @@ 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 */
@@ -3881,7 +3909,7 @@ 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);
@@ -3901,7 +3929,7 @@ 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);

block/ioctl.c

@@ -294,11 +294,12 @@ int blkdev_ioctl(struct block_device *bdev, fmode_t mode, unsigned cmd,
 			return -EINVAL;
 		if (get_user(n, (int __user *) arg))
 			return -EFAULT;
-		if (!(mode & FMODE_EXCL) && bd_claim(bdev, &bdev) < 0)
+		if (!(mode & FMODE_EXCL) &&
+		    blkdev_get(bdev, mode | FMODE_EXCL, &bdev) < 0)
 			return -EBUSY;
 		ret = set_blocksize(bdev, n);
 		if (!(mode & FMODE_EXCL))
-			bd_release(bdev);
+			blkdev_put(bdev, mode | FMODE_EXCL);
 		return ret;
 	case BLKPG:
 		ret = blkpg_ioctl(bdev, (struct blkpg_ioctl_arg __user *) arg);