Merge branch 'for-linus' of git://git.kernel.dk/linux-2.6-block

* 'for-linus' of git://git.kernel.dk/linux-2.6-block: (27 commits)
  block: make blk_init_free_list and elevator_init idempotent
  block: avoid unconditionally freeing previously allocated request_queue
  pipe: change /proc/sys/fs/pipe-max-pages to byte sized interface
  pipe: change the privilege required for growing a pipe beyond system max
  pipe: adjust minimum pipe size to 1 page
  block: disable preemption before using sched_clock()
  cciss: call BUG() earlier
  Preparing 8.3.8rc2
  drbd: Reduce verbosity
  drbd: use drbd specific ratelimit instead of global printk_ratelimit
  drbd: fix hang on local read errors while disconnected
  drbd: Removed the now empty w_io_error() function
  drbd: removed duplicated #includes
  drbd: improve usage of MSG_MORE
  drbd: need to set socket bufsize early to take effect
  drbd: improve network latency, TCP_QUICKACK
  drbd: Revert "drbd: Create new current UUID as late as possible"
  brd: support discard
  Revert "writeback: fix WB_SYNC_NONE writeback from umount"
  Revert "writeback: ensure that WB_SYNC_NONE writeback with sb pinned is sync"
  ...

block/blk-core.c

@@ -467,6 +467,9 @@ static int blk_init_free_list(struct request_queue *q)
 {
 	struct request_list *rl = &q->rq;
 
+	if (unlikely(rl->rq_pool))
+		return 0;
+
 	rl->count[BLK_RW_SYNC] = rl->count[BLK_RW_ASYNC] = 0;
 	rl->starved[BLK_RW_SYNC] = rl->starved[BLK_RW_ASYNC] = 0;
 	rl->elvpriv = 0;
@@ -570,9 +573,17 @@ EXPORT_SYMBOL(blk_init_queue);
 struct request_queue *
 blk_init_queue_node(request_fn_proc *rfn, spinlock_t *lock, int node_id)
 {
-	struct request_queue *q = blk_alloc_queue_node(GFP_KERNEL, node_id);
+	struct request_queue *uninit_q, *q;
+
+	uninit_q = blk_alloc_queue_node(GFP_KERNEL, node_id);
+	if (!uninit_q)
+		return NULL;
+
+	q = blk_init_allocated_queue_node(uninit_q, rfn, lock, node_id);
+	if (!q)
+		blk_cleanup_queue(uninit_q);
 
-	return blk_init_allocated_queue_node(q, rfn, lock, node_id);
+	return q;
 }
 EXPORT_SYMBOL(blk_init_queue_node);
 
@@ -592,10 +603,8 @@ blk_init_allocated_queue_node(struct request_queue *q, request_fn_proc *rfn,
 		return NULL;
 
 	q->node = node_id;
-	if (blk_init_free_list(q)) {
-		kmem_cache_free(blk_requestq_cachep, q);
+	if (blk_init_free_list(q))
 		return NULL;
-	}
 
 	q->request_fn		= rfn;
 	q->prep_rq_fn		= NULL;
@@ -618,7 +627,6 @@ blk_init_allocated_queue_node(struct request_queue *q, request_fn_proc *rfn,
 		return q;
 	}
 
-	blk_put_queue(q);
 	return NULL;
 }
 EXPORT_SYMBOL(blk_init_allocated_queue_node);

block/cfq-iosched.c

@@ -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;
 }
@@ -3708,21 +3736,49 @@ 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;
 	int i, j;
 	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();
 }
 

block/elevator.c

@@ -242,9 +242,11 @@ int elevator_init(struct request_queue *q, char *name)
 {
 	struct elevator_type *e = NULL;
 	struct elevator_queue *eq;
-	int ret = 0;
 	void *data;
 
+	if (unlikely(q->elevator))
+		return 0;
+
 	INIT_LIST_HEAD(&q->queue_head);
 	q->last_merge = NULL;
 	q->end_sector = 0;
@@ -284,7 +286,7 @@ int elevator_init(struct request_queue *q, char *name)
 	}
 
 	elevator_attach(q, eq, data);
-	return ret;
+	return 0;
 }
 EXPORT_SYMBOL(elevator_init);
 
@@ -1097,7 +1099,7 @@ ssize_t elv_iosched_show(struct request_queue *q, char *name)
 	struct elevator_type *__e;
 	int len = 0;
 
-	if (!q->elevator)
+	if (!q->elevator || !blk_queue_stackable(q))
 		return sprintf(name, "none\n");
 
 	elv = e->elevator_type;