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"
  ...

23 files changed, 311 insertions, 264 deletions

diff --git a/block/blk-core.c b/block/blk-core.c
index 3bc5579d6f5..f84cce42fc5 100644
--- a/block/blk-core.c
+++ b/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);
diff --git a/block/cfq-iosched.c b/block/cfq-iosched.c
index ed897b5ef31..5ff4f4850e7 100644
--- a/block/cfq-iosched.c
+++ b/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;
 }
@@ -3708,10 +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();
 }
 
diff --git a/block/elevator.c b/block/elevator.c
index 6df2b5056b5..923a9139106 100644
--- a/block/elevator.c
+++ b/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;
diff --git a/drivers/block/brd.c b/drivers/block/brd.c
index 6081e81d573..f1bf79d9bc0 100644
--- a/drivers/block/brd.c
+++ b/drivers/block/brd.c
@@ -133,6 +133,28 @@ static struct page *brd_insert_page(struct brd_device *brd, sector_t sector)
 	return page;
 }
 
+static void brd_free_page(struct brd_device *brd, sector_t sector)
+{
+	struct page *page;
+	pgoff_t idx;
+
+	spin_lock(&brd->brd_lock);
+	idx = sector >> PAGE_SECTORS_SHIFT;
+	page = radix_tree_delete(&brd->brd_pages, idx);
+	spin_unlock(&brd->brd_lock);
+	if (page)
+		__free_page(page);
+}
+
+static void brd_zero_page(struct brd_device *brd, sector_t sector)
+{
+	struct page *page;
+
+	page = brd_lookup_page(brd, sector);
+	if (page)
+		clear_highpage(page);
+}
+
 /*
  * Free all backing store pages and radix tree. This must only be called when
  * there are no other users of the device.
@@ -189,6 +211,24 @@ static int copy_to_brd_setup(struct brd_device *brd, sector_t sector, size_t n)
 	return 0;
 }
 
+static void discard_from_brd(struct brd_device *brd,
+			sector_t sector, size_t n)
+{
+	while (n >= PAGE_SIZE) {
+		/*
+		 * Don't want to actually discard pages here because
+		 * re-allocating the pages can result in writeback
+		 * deadlocks under heavy load.
+		 */
+		if (0)
+			brd_free_page(brd, sector);
+		else
+			brd_zero_page(brd, sector);
+		sector += PAGE_SIZE >> SECTOR_SHIFT;
+		n -= PAGE_SIZE;
+	}
+}
+
 /*
  * Copy n bytes from src to the brd starting at sector. Does not sleep.
  */
@@ -300,6 +340,12 @@ static int brd_make_request(struct request_queue *q, struct bio *bio)
 						get_capacity(bdev->bd_disk))
 		goto out;
 
+	if (unlikely(bio_rw_flagged(bio, BIO_RW_DISCARD))) {
+		err = 0;
+		discard_from_brd(brd, sector, bio->bi_size);
+		goto out;
+	}
+
 	rw = bio_rw(bio);
 	if (rw == READA)
 		rw = READ;
@@ -320,7 +366,7 @@ out:
 }
 
 #ifdef CONFIG_BLK_DEV_XIP
-static int brd_direct_access (struct block_device *bdev, sector_t sector,
+static int brd_direct_access(struct block_device *bdev, sector_t sector,
 			void **kaddr, unsigned long *pfn)
 {
 	struct brd_device *brd = bdev->bd_disk->private_data;
@@ -437,6 +483,11 @@ static struct brd_device *brd_alloc(int i)
 	blk_queue_max_hw_sectors(brd->brd_queue, 1024);
 	blk_queue_bounce_limit(brd->brd_queue, BLK_BOUNCE_ANY);
 
+	brd->brd_queue->limits.discard_granularity = PAGE_SIZE;
+	brd->brd_queue->limits.max_discard_sectors = UINT_MAX;
+	brd->brd_queue->limits.discard_zeroes_data = 1;
+	queue_flag_set_unlocked(QUEUE_FLAG_DISCARD, brd->brd_queue);
+
 	disk = brd->brd_disk = alloc_disk(1 << part_shift);
 	if (!disk)
 		goto out_free_queue;
diff --git a/drivers/block/cciss_scsi.c b/drivers/block/cciss_scsi.c
index e1d0e2cfec7..3381505c8a6 100644
--- a/drivers/block/cciss_scsi.c
+++ b/drivers/block/cciss_scsi.c
@@ -188,11 +188,11 @@ scsi_cmd_free(ctlr_info_t *h, CommandList_struct *cmd)
 
 	sa = h->scsi_ctlr;
 	stk = &sa->cmd_stack; 
+	stk->top++;
 	if (stk->top >= CMD_STACK_SIZE) {
 		printk("cciss: scsi_cmd_free called too many times.\n");
 		BUG();
 	}
-	stk->top++;
 	stk->elem[stk->top] = (struct cciss_scsi_cmd_stack_elem_t *) cmd;
 }
 
diff --git a/drivers/block/drbd/drbd_int.h b/drivers/block/drbd/drbd_int.h
index e9654c8d5b6..485ed8c7d62 100644
--- a/drivers/block/drbd/drbd_int.h
+++ b/drivers/block/drbd/drbd_int.h
@@ -943,8 +943,7 @@ struct drbd_conf {
 	struct drbd_work  resync_work,
 			  unplug_work,
 			  md_sync_work,
-			  delay_probe_work,
-			  uuid_work;
+			  delay_probe_work;
 	struct timer_list resync_timer;
 	struct timer_list md_sync_timer;
 	struct timer_list delay_probe_timer;
@@ -1069,7 +1068,6 @@ struct drbd_conf {
 	struct timeval dps_time; /* delay-probes-start-time */
 	unsigned int dp_volume_last;  /* send_cnt of last delay probe */
 	int c_sync_rate; /* current resync rate after delay_probe magic */
-	atomic_t new_c_uuid;
 };
 
 static inline struct drbd_conf *minor_to_mdev(unsigned int minor)
@@ -1476,7 +1474,6 @@ extern int w_e_end_ov_req(struct drbd_conf *, struct drbd_work *, int);
 extern int w_ov_finished(struct drbd_conf *, struct drbd_work *, int);
 extern int w_resync_inactive(struct drbd_conf *, struct drbd_work *, int);
 extern int w_resume_next_sg(struct drbd_conf *, struct drbd_work *, int);
-extern int w_io_error(struct drbd_conf *, struct drbd_work *, int);
 extern int w_send_write_hint(struct drbd_conf *, struct drbd_work *, int);
 extern int w_make_resync_request(struct drbd_conf *, struct drbd_work *, int);
 extern int w_send_dblock(struct drbd_conf *, struct drbd_work *, int);
@@ -1542,7 +1539,7 @@ static inline void drbd_tcp_nodelay(struct socket *sock)
 
 static inline void drbd_tcp_quickack(struct socket *sock)
 {
-	int __user val = 1;
+	int __user val = 2;
 	(void) drbd_setsockopt(sock, SOL_TCP, TCP_QUICKACK,
 			(char __user *)&val, sizeof(val));
 }
@@ -1728,7 +1725,7 @@ static inline void __drbd_chk_io_error_(struct drbd_conf *mdev, int forcedetach,
 	switch (mdev->ldev->dc.on_io_error) {
 	case EP_PASS_ON:
 		if (!forcedetach) {
-			if (printk_ratelimit())
+			if (__ratelimit(&drbd_ratelimit_state))
 				dev_err(DEV, "Local IO failed in %s."
 					     "Passing error on...\n", where);
 			break;
@@ -2219,8 +2216,6 @@ static inline int __inc_ap_bio_cond(struct drbd_conf *mdev)
 		return 0;
 	if (test_bit(BITMAP_IO, &mdev->flags))
 		return 0;
-	if (atomic_read(&mdev->new_c_uuid))
-		return 0;
 	return 1;
 }
 
@@ -2241,9 +2236,6 @@ static inline void inc_ap_bio(struct drbd_conf *mdev, int count)
 	 * to avoid races with the reconnect code,
 	 * we need to atomic_inc within the spinlock. */
 
-	if (atomic_read(&mdev->new_c_uuid) && atomic_add_unless(&mdev->new_c_uuid, -1, 1))
-		drbd_queue_work_front(&mdev->data.work, &mdev->uuid_work);
-
 	spin_lock_irq(&mdev->req_lock);
 	while (!__inc_ap_bio_cond(mdev)) {
 		prepare_to_wait(&mdev->misc_wait, &wait, TASK_UNINTERRUPTIBLE);
diff --git a/drivers/block/drbd/drbd_main.c b/drivers/block/drbd/drbd_main.c
index be2d2da9cdb..6b077f93acc 100644
--- a/drivers/block/drbd/drbd_main.c
+++ b/drivers/block/drbd/drbd_main.c
@@ -1215,18 +1215,17 @@ static void after_state_ch(struct drbd_conf *mdev, union drbd_state os,
 	     ns.pdsk == D_OUTDATED)) {
 		if (get_ldev(mdev)) {
 			if ((ns.role == R_PRIMARY || ns.peer == R_PRIMARY) &&
-			    mdev->ldev->md.uuid[UI_BITMAP] == 0 && ns.disk >= D_UP_TO_DATE &&
-			    !atomic_read(&mdev->new_c_uuid))
-				atomic_set(&mdev->new_c_uuid, 2);
+			    mdev->ldev->md.uuid[UI_BITMAP] == 0 && ns.disk >= D_UP_TO_DATE) {
+				drbd_uuid_new_current(mdev);
+				drbd_send_uuids(mdev);
+			}
 			put_ldev(mdev);
 		}
 	}
 
 	if (ns.pdsk < D_INCONSISTENT && get_ldev(mdev)) {
-		/* Diskless peer becomes primary or got connected do diskless, primary peer. */
-		if (ns.peer == R_PRIMARY && mdev->ldev->md.uuid[UI_BITMAP] == 0 &&
-		    !atomic_read(&mdev->new_c_uuid))
-			atomic_set(&mdev->new_c_uuid, 2);
+		if (ns.peer == R_PRIMARY && mdev->ldev->md.uuid[UI_BITMAP] == 0)
+			drbd_uuid_new_current(mdev);
 
 		/* D_DISKLESS Peer becomes secondary */
 		if (os.peer == R_PRIMARY && ns.peer == R_SECONDARY)
@@ -1350,24 +1349,6 @@ static void after_state_ch(struct drbd_conf *mdev, union drbd_state os,
 	drbd_md_sync(mdev);
 }
 
-static int w_new_current_uuid(struct drbd_conf *mdev, struct drbd_work *w, int cancel)
-{
-	if (get_ldev(mdev)) {
-		if (mdev->ldev->md.uuid[UI_BITMAP] == 0) {
-			drbd_uuid_new_current(mdev);
-			if (get_net_conf(mdev)) {
-				drbd_send_uuids(mdev);
-				put_net_conf(mdev);
-			}
-			drbd_md_sync(mdev);
-		}
-		put_ldev(mdev);
-	}
-	atomic_dec(&mdev->new_c_uuid);
-	wake_up(&mdev->misc_wait);
-
-	return 1;
-}
 
 static int drbd_thread_setup(void *arg)
 {
@@ -2291,9 +2272,9 @@ static int we_should_drop_the_connection(struct drbd_conf *mdev, struct socket *
  * with page_count == 0 or PageSlab.
  */
 static int _drbd_no_send_page(struct drbd_conf *mdev, struct page *page,
-		   int offset, size_t size)
+		   int offset, size_t size, unsigned msg_flags)
 {
-	int sent = drbd_send(mdev, mdev->data.socket, kmap(page) + offset, size, 0);
+	int sent = drbd_send(mdev, mdev->data.socket, kmap(page) + offset, size, msg_flags);
 	kunmap(page);
 	if (sent == size)
 		mdev->send_cnt += size>>9;
@@ -2301,7 +2282,7 @@ static int _drbd_no_send_page(struct drbd_conf *mdev, struct page *page,
 }
 
 static int _drbd_send_page(struct drbd_conf *mdev, struct page *page,
-		    int offset, size_t size)
+		    int offset, size_t size, unsigned msg_flags)
 {
 	mm_segment_t oldfs = get_fs();
 	int sent, ok;
@@ -2314,14 +2295,15 @@ static int _drbd_send_page(struct drbd_conf *mdev, struct page *page,
 	 * __page_cache_release a page that would actually still be referenced
 	 * by someone, leading to some obscure delayed Oops somewhere else. */
 	if (disable_sendpage || (page_count(page) < 1) || PageSlab(page))
-		return _drbd_no_send_page(mdev, page, offset, size);
+		return _drbd_no_send_page(mdev, page, offset, size, msg_flags);
 
+	msg_flags |= MSG_NOSIGNAL;
 	drbd_update_congested(mdev);
 	set_fs(KERNEL_DS);
 	do {
 		sent = mdev->data.socket->ops->sendpage(mdev->data.socket, page,
 							offset, len,
-							MSG_NOSIGNAL);
+							msg_flags);
 		if (sent == -EAGAIN) {
 			if (we_should_drop_the_connection(mdev,
 							  mdev->data.socket))
@@ -2350,9 +2332,11 @@ static int _drbd_send_bio(struct drbd_conf *mdev, struct bio *bio)
 {
 	struct bio_vec *bvec;
 	int i;
+	/* hint all but last page with MSG_MORE */
 	__bio_for_each_segment(bvec, bio, i, 0) {
 		if (!_drbd_no_send_page(mdev, bvec->bv_page,
-				     bvec->bv_offset, bvec->bv_len))
+				     bvec->bv_offset, bvec->bv_len,
+				     i == bio->bi_vcnt -1 ? 0 : MSG_MORE))
 			return 0;
 	}
 	return 1;
@@ -2362,12 +2346,13 @@ static int _drbd_send_zc_bio(struct drbd_conf *mdev, struct bio *bio)
 {
 	struct bio_vec *bvec;
 	int i;
+	/* hint all but last page with MSG_MORE */
 	__bio_for_each_segment(bvec, bio, i, 0) {
 		if (!_drbd_send_page(mdev, bvec->bv_page,
-				     bvec->bv_offset, bvec->bv_len))
+				     bvec->bv_offset, bvec->bv_len,
+				     i == bio->bi_vcnt -1 ? 0 : MSG_MORE))
 			return 0;
 	}
-
 	return 1;
 }
 
@@ -2375,9 +2360,11 @@ static int _drbd_send_zc_ee(struct drbd_conf *mdev, struct drbd_epoch_entry *e)
 {
 	struct page *page = e->pages;
 	unsigned len = e->size;
+	/* hint all but last page with MSG_MORE */
 	page_chain_for_each(page) {
 		unsigned l = min_t(unsigned, len, PAGE_SIZE);
-		if (!_drbd_send_page(mdev, page, 0, l))
+		if (!_drbd_send_page(mdev, page, 0, l,
+				page_chain_next(page) ? MSG_MORE : 0))
 			return 0;
 		len -= l;
 	}
@@ -2457,11 +2444,11 @@ int drbd_send_dblock(struct drbd_conf *mdev, struct drbd_request *req)
 	p.dp_flags = cpu_to_be32(dp_flags);
 	set_bit(UNPLUG_REMOTE, &mdev->flags);
 	ok = (sizeof(p) ==
-		drbd_send(mdev, mdev->data.socket, &p, sizeof(p), MSG_MORE));
+		drbd_send(mdev, mdev->data.socket, &p, sizeof(p), dgs ? MSG_MORE : 0));
 	if (ok && dgs) {
 		dgb = mdev->int_dig_out;
 		drbd_csum_bio(mdev, mdev->integrity_w_tfm, req->master_bio, dgb);
-		ok = drbd_send(mdev, mdev->data.socket, dgb, dgs, MSG_MORE);
+		ok = drbd_send(mdev, mdev->data.socket, dgb, dgs, 0);
 	}
 	if (ok) {
 		if (mdev->net_conf->wire_protocol == DRBD_PROT_A)
@@ -2510,11 +2497,11 @@ int drbd_send_block(struct drbd_conf *mdev, enum drbd_packets cmd,
 		return 0;
 
 	ok = sizeof(p) == drbd_send(mdev, mdev->data.socket, &p,
-					sizeof(p), MSG_MORE);
+					sizeof(p), dgs ? MSG_MORE : 0);
 	if (ok && dgs) {
 		dgb = mdev->int_dig_out;
 		drbd_csum_ee(mdev, mdev->integrity_w_tfm, e, dgb);
-		ok = drbd_send(mdev, mdev->data.socket, dgb, dgs, MSG_MORE);
+		ok = drbd_send(mdev, mdev->data.socket, dgb, dgs, 0);
 	}
 	if (ok)
 		ok = _drbd_send_zc_ee(mdev, e);
@@ -2708,7 +2695,6 @@ void drbd_init_set_defaults(struct drbd_conf *mdev)
 	atomic_set(&mdev->net_cnt, 0);
 	atomic_set(&mdev->packet_seq, 0);
 	atomic_set(&mdev->pp_in_use, 0);
-	atomic_set(&mdev->new_c_uuid, 0);
 
 	mutex_init(&mdev->md_io_mutex);
 	mutex_init(&mdev->data.mutex);
@@ -2739,14 +2725,12 @@ void drbd_init_set_defaults(struct drbd_conf *mdev)
 	INIT_LIST_HEAD(&mdev->bm_io_work.w.list);
 	INIT_LIST_HEAD(&mdev->delay_probes);
 	INIT_LIST_HEAD(&mdev->delay_probe_work.list);
-	INIT_LIST_HEAD(&mdev->uuid_work.list);
 
 	mdev->resync_work.cb  = w_resync_inactive;
 	mdev->unplug_work.cb  = w_send_write_hint;
 	mdev->md_sync_work.cb = w_md_sync;
 	mdev->bm_io_work.w.cb = w_bitmap_io;
 	mdev->delay_probe_work.cb = w_delay_probes;
-	mdev->uuid_work.cb = w_new_current_uuid;
 	init_timer(&mdev->resync_timer);
 	init_timer(&mdev->md_sync_timer);
 	init_timer(&mdev->delay_probe_timer);
@@ -3799,7 +3783,7 @@ _drbd_insert_fault(struct drbd_conf *mdev, unsigned int type)
 	if (ret) {
 		fault_count++;
 
-		if (printk_ratelimit())
+		if (__ratelimit(&drbd_ratelimit_state))
 			dev_warn(DEV, "***Simulating %s failure\n",
 				_drbd_fault_str(type));
 	}
diff --git a/drivers/block/drbd/drbd_receiver.c b/drivers/block/drbd/drbd_receiver.c
index bc9ab7fb2cc..dff48701b84 100644
--- a/drivers/block/drbd/drbd_receiver.c
+++ b/drivers/block/drbd/drbd_receiver.c
@@ -42,7 +42,6 @@
 #include <linux/unistd.h>
 #include <linux/vmalloc.h>
 #include <linux/random.h>
-#include <linux/mm.h>
 #include <linux/string.h>
 #include <linux/scatterlist.h>
 #include "drbd_int.h"
@@ -571,6 +570,25 @@ static int drbd_recv(struct drbd_conf *mdev, void *buf, size_t size)
 	return rv;
 }
 
+/* quoting tcp(7):
+ *   On individual connections, the socket buffer size must be set prior to the
+ *   listen(2) or connect(2) calls in order to have it take effect.
+ * This is our wrapper to do so.
+ */
+static void drbd_setbufsize(struct socket *sock, unsigned int snd,
+		unsigned int rcv)
+{
+	/* open coded SO_SNDBUF, SO_RCVBUF */
+	if (snd) {
+		sock->sk->sk_sndbuf = snd;
+		sock->sk->sk_userlocks |= SOCK_SNDBUF_LOCK;
+	}
+	if (rcv) {
+		sock->sk->sk_rcvbuf = rcv;
+		sock->sk->sk_userlocks |= SOCK_RCVBUF_LOCK;
+	}
+}
+
 static struct socket *drbd_try_connect(struct drbd_conf *mdev)
 {
 	const char *what;
@@ -592,6 +610,8 @@ static struct socket *drbd_try_connect(struct drbd_conf *mdev)
 
 	sock->sk->sk_rcvtimeo =
 	sock->sk->sk_sndtimeo =  mdev->net_conf->try_connect_int*HZ;
+	drbd_setbufsize(sock, mdev->net_conf->sndbuf_size,
+			mdev->net_conf->rcvbuf_size);
 
        /* explicitly bind to the configured IP as source IP
 	*  for the outgoing connections.
@@ -670,6 +690,8 @@ static struct socket *drbd_wait_for_connect(struct drbd_conf *mdev)
 	s_listen->sk->sk_reuse    = 1; /* SO_REUSEADDR */
 	s_listen->sk->sk_rcvtimeo = timeo;
 	s_listen->sk->sk_sndtimeo = timeo;
+	drbd_setbufsize(s_listen, mdev->net_conf->sndbuf_size,
+			mdev->net_conf->rcvbuf_size);
 
 	what = "bind before listen";
 	err = s_listen->ops->bind(s_listen,
@@ -856,16 +878,6 @@ retry:
 	sock->sk->sk_priority = TC_PRIO_INTERACTIVE_BULK;
 	msock->sk->sk_priority = TC_PRIO_INTERACTIVE;
 
-	if (mdev->net_conf->sndbuf_size) {
-		sock->sk->sk_sndbuf = mdev->net_conf->sndbuf_size;
-		sock->sk->sk_userlocks |= SOCK_SNDBUF_LOCK;
-	}
-
-	if (mdev->net_conf->rcvbuf_size) {
-		sock->sk->sk_rcvbuf = mdev->net_conf->rcvbuf_size;
-		sock->sk->sk_userlocks |= SOCK_RCVBUF_LOCK;
-	}
-
 	/* NOT YET ...
 	 * sock->sk->sk_sndtimeo = mdev->net_conf->timeout*HZ/10;
 	 * sock->sk->sk_rcvtimeo = MAX_SCHEDULE_TIMEOUT;
@@ -1154,17 +1166,6 @@ int drbd_submit_ee(struct drbd_conf *mdev, struct drbd_epoch_entry *e,
 	unsigned n_bios = 0;
 	unsigned nr_pages = (ds + PAGE_SIZE -1) >> PAGE_SHIFT;
 
-	if (atomic_read(&mdev->new_c_uuid)) {
-		if (atomic_add_unless(&mdev->new_c_uuid, -1, 1)) {
-			drbd_uuid_new_current(mdev);
-			drbd_md_sync(mdev);
-
-			atomic_dec(&mdev->new_c_uuid);
-			wake_up(&mdev->misc_wait);
-		}
-		wait_event(mdev->misc_wait, !atomic_read(&mdev->new_c_uuid));
-	}
-
 	/* In most cases, we will only need one bio.  But in case the lower
 	 * level restrictions happen to be different at this offset on this
 	 * side than those of the sending peer, we may need to submit the
diff --git a/drivers/block/drbd/drbd_req.c b/drivers/block/drbd/drbd_req.c
index 3397f11d0ba..654f1ef5cbb 100644
--- a/drivers/block/drbd/drbd_req.c
+++ b/drivers/block/drbd/drbd_req.c
@@ -102,32 +102,7 @@ static void _req_is_done(struct drbd_conf *mdev, struct drbd_request *req, const
 		}
 	}
 
-	/* if it was a local io error, we want to notify our
-	 * peer about that, and see if we need to
-	 * detach the disk and stuff.
-	 * to avoid allocating some special work
-	 * struct, reuse the request. */
-
-	/* THINK
-	 * why do we do this not when we detect the error,
-	 * but delay it until it is "done", i.e. possibly
-	 * until the next barrier ack? */
-
-	if (rw == WRITE &&
-	    ((s & RQ_LOCAL_MASK) && !(s & RQ_LOCAL_OK))) {
-		if (!(req->w.list.next == LIST_POISON1 ||
-		      list_empty(&req->w.list))) {
-			/* DEBUG ASSERT only; if this triggers, we
-			 * probably corrupt the worker list here */
-			dev_err(DEV, "req->w.list.next = %p\n", req->w.list.next);
-			dev_err(DEV, "req->w.list.prev = %p\n", req->w.list.prev);
-		}
-		req->w.cb = w_io_error;
-		drbd_queue_work(&mdev->data.work, &req->w);
-		/* drbd_req_free() is done in w_io_error */
-	} else {
-		drbd_req_free(req);
-	}
+	drbd_req_free(req);
 }
 
 static void queue_barrier(struct drbd_conf *mdev)
@@ -453,9 +428,6 @@ void __req_mod(struct drbd_request *req, enum drbd_req_event what,
 		req->rq_state |= RQ_LOCAL_COMPLETED;
 		req->rq_state &= ~RQ_LOCAL_PENDING;
 
-		dev_alert(DEV, "Local WRITE failed sec=