diff --git a/[refs] b/[refs]
index 808edebd41e8..f2197f2b5a66 100644
--- a/[refs]
+++ b/[refs]
@@ -1,2 +1,2 @@
 ---
-refs/heads/master: 23978161f90e5a3200ad6ac9b0d534911e4cbb28
+refs/heads/master: 2d1ee87d8763b38668f6f11bb53abb689a49a43e
diff --git a/trunk/block/blk-ioc.c b/trunk/block/blk-ioc.c
index 98e6bf61b0ac..cbdabb0dd6d7 100644
--- a/trunk/block/blk-ioc.c
+++ b/trunk/block/blk-ioc.c
@@ -39,6 +39,8 @@ int put_io_context(struct io_context *ioc)
 
 	if (atomic_long_dec_and_test(&ioc->refcount)) {
 		rcu_read_lock();
+		if (ioc->aic && ioc->aic->dtor)
+			ioc->aic->dtor(ioc->aic);
 		cfq_dtor(ioc);
 		rcu_read_unlock();
 
@@ -74,6 +76,8 @@ void exit_io_context(struct task_struct *task)
 	task_unlock(task);
 
 	if (atomic_dec_and_test(&ioc->nr_tasks)) {
+		if (ioc->aic && ioc->aic->exit)
+			ioc->aic->exit(ioc->aic);
 		cfq_exit(ioc);
 
 	}
@@ -93,6 +97,7 @@ struct io_context *alloc_io_context(gfp_t gfp_flags, int node)
 		ret->ioprio = 0;
 		ret->last_waited = jiffies; /* doesn't matter... */
 		ret->nr_batch_requests = 0; /* because this is 0 */
+		ret->aic = NULL;
 		INIT_RADIX_TREE(&ret->radix_root, GFP_ATOMIC | __GFP_HIGH);
 		INIT_HLIST_HEAD(&ret->cic_list);
 		ret->ioc_data = NULL;
diff --git a/trunk/block/blk-settings.c b/trunk/block/blk-settings.c
index 5eeb9e0d256e..d52d4adc440b 100644
--- a/trunk/block/blk-settings.c
+++ b/trunk/block/blk-settings.c
@@ -528,7 +528,7 @@ int blk_stack_limits(struct queue_limits *t, struct queue_limits *b,
 		     sector_t offset)
 {
 	sector_t alignment;
-	unsigned int top, bottom, ret = 0;
+	unsigned int top, bottom;
 
 	t->max_sectors = min_not_zero(t->max_sectors, b->max_sectors);
 	t->max_hw_sectors = min_not_zero(t->max_hw_sectors, b->max_hw_sectors);
@@ -546,8 +546,6 @@ int blk_stack_limits(struct queue_limits *t, struct queue_limits *b,
 	t->max_segment_size = min_not_zero(t->max_segment_size,
 					   b->max_segment_size);
 
-	t->misaligned |= b->misaligned;
-
 	alignment = queue_limit_alignment_offset(b, offset);
 
 	/* Bottom device has different alignment.  Check that it is
@@ -560,10 +558,8 @@ int blk_stack_limits(struct queue_limits *t, struct queue_limits *b,
 		bottom = max(b->physical_block_size, b->io_min) + alignment;
 
 		/* Verify that top and bottom intervals line up */
-		if (max(top, bottom) & (min(top, bottom) - 1)) {
+		if (max(top, bottom) & (min(top, bottom) - 1))
 			t->misaligned = 1;
-			ret = -1;
-		}
 	}
 
 	t->logical_block_size = max(t->logical_block_size,
@@ -582,21 +578,18 @@ int blk_stack_limits(struct queue_limits *t, struct queue_limits *b,
 	if (t->physical_block_size & (t->logical_block_size - 1)) {
 		t->physical_block_size = t->logical_block_size;
 		t->misaligned = 1;
-		ret = -1;
 	}
 
 	/* Minimum I/O a multiple of the physical block size? */
 	if (t->io_min & (t->physical_block_size - 1)) {
 		t->io_min = t->physical_block_size;
 		t->misaligned = 1;
-		ret = -1;
 	}
 
 	/* Optimal I/O a multiple of the physical block size? */
 	if (t->io_opt & (t->physical_block_size - 1)) {
 		t->io_opt = 0;
 		t->misaligned = 1;
-		ret = -1;
 	}
 
 	/* Find lowest common alignment_offset */
@@ -604,10 +597,8 @@ int blk_stack_limits(struct queue_limits *t, struct queue_limits *b,
 		& (max(t->physical_block_size, t->io_min) - 1);
 
 	/* Verify that new alignment_offset is on a logical block boundary */
-	if (t->alignment_offset & (t->logical_block_size - 1)) {
+	if (t->alignment_offset & (t->logical_block_size - 1))
 		t->misaligned = 1;
-		ret = -1;
-	}
 
 	/* Discard alignment and granularity */
 	if (b->discard_granularity) {
@@ -635,32 +626,10 @@ int blk_stack_limits(struct queue_limits *t, struct queue_limits *b,
 			(t->discard_granularity - 1);
 	}
 
-	return ret;
+	return t->misaligned ? -1 : 0;
 }
 EXPORT_SYMBOL(blk_stack_limits);
 
-/**
- * bdev_stack_limits - adjust queue limits for stacked drivers
- * @t:	the stacking driver limits (top device)
- * @bdev:  the component block_device (bottom)
- * @start:  first data sector within component device
- *
- * Description:
- *    Merges queue limits for a top device and a block_device.  Returns
- *    0 if alignment didn't change.  Returns -1 if adding the bottom
- *    device caused misalignment.
- */
-int bdev_stack_limits(struct queue_limits *t, struct block_device *bdev,
-		      sector_t start)
-{
-	struct request_queue *bq = bdev_get_queue(bdev);
-
-	start += get_start_sect(bdev);
-
-	return blk_stack_limits(t, &bq->limits, start << 9);
-}
-EXPORT_SYMBOL(bdev_stack_limits);
-
 /**
  * disk_stack_limits - adjust queue limits for stacked drivers
  * @disk:  MD/DM gendisk (top)
diff --git a/trunk/block/cfq-iosched.c b/trunk/block/cfq-iosched.c
index ee130f14d1fc..918c7fd9aeb1 100644
--- a/trunk/block/cfq-iosched.c
+++ b/trunk/block/cfq-iosched.c
@@ -3076,12 +3076,6 @@ cfq_should_preempt(struct cfq_data *cfqd, struct cfq_queue *new_cfqq,
 	if (cfq_class_idle(cfqq))
 		return true;
 
-	/*
-	 * Don't allow a non-RT request to preempt an ongoing RT cfqq timeslice.
-	 */
-	if (cfq_class_rt(cfqq) && !cfq_class_rt(new_cfqq))
-		return false;
-
 	/*
 	 * if the new request is sync, but the currently running queue is
 	 * not, let the sync request have priority.
diff --git a/trunk/block/genhd.c b/trunk/block/genhd.c
index d13ba76a169c..b11a4ad7d571 100644
--- a/trunk/block/genhd.c
+++ b/trunk/block/genhd.c
@@ -867,7 +867,7 @@ static ssize_t disk_discard_alignment_show(struct device *dev,
 {
 	struct gendisk *disk = dev_to_disk(dev);
 
-	return sprintf(buf, "%d\n", queue_discard_alignment(disk->queue));
+	return sprintf(buf, "%u\n", queue_discard_alignment(disk->queue));
 }
 
 static DEVICE_ATTR(range, S_IRUGO, disk_range_show, NULL);
diff --git a/trunk/drivers/md/dm-table.c b/trunk/drivers/md/dm-table.c
index 4b22feb01a0c..be625475cf6d 100644
--- a/trunk/drivers/md/dm-table.c
+++ b/trunk/drivers/md/dm-table.c
@@ -503,15 +503,16 @@ int dm_set_device_limits(struct dm_target *ti, struct dm_dev *dev,
 		return 0;
 	}
 
-	if (bdev_stack_limits(limits, bdev, start) < 0)
-		DMWARN("%s: adding target device %s caused an alignment inconsistency: "
+	if (blk_stack_limits(limits, &q->limits, start << 9) < 0)
+		DMWARN("%s: target device %s is misaligned: "
 		       "physical_block_size=%u, logical_block_size=%u, "
 		       "alignment_offset=%u, start=%llu",
 		       dm_device_name(ti->table->md), bdevname(bdev, b),
 		       q->limits.physical_block_size,
 		       q->limits.logical_block_size,
 		       q->limits.alignment_offset,
-		       (unsigned long long) start << SECTOR_SHIFT);
+		       (unsigned long long) start << 9);
+
 
 	/*
 	 * Check if merge fn is supported.
@@ -1025,9 +1026,9 @@ int dm_calculate_queue_limits(struct dm_table *table,
 		 * for the table.
 		 */
 		if (blk_stack_limits(limits, &ti_limits, 0) < 0)
-			DMWARN("%s: adding target device "
+			DMWARN("%s: target device "
 			       "(start sect %llu len %llu) "
-			       "caused an alignment inconsistency",
+			       "is misaligned",
 			       dm_device_name(table->md),
 			       (unsigned long long) ti->begin,
 			       (unsigned long long) ti->len);
@@ -1078,6 +1079,15 @@ static void dm_table_set_integrity(struct dm_table *t)
 void dm_table_set_restrictions(struct dm_table *t, struct request_queue *q,
 			       struct queue_limits *limits)
 {
+	/*
+	 * Each target device in the table has a data area that should normally
+	 * be aligned such that the DM device's alignment_offset is 0.
+	 * FIXME: Propagate alignment_offsets up the stack and warn of
+	 *	  sub-optimal or inconsistent settings.
+	 */
+	limits->alignment_offset = 0;
+	limits->misaligned = 0;
+
 	/*
 	 * Copy table's limits to the DM device's request_queue
 	 */
diff --git a/trunk/include/linux/blkdev.h b/trunk/include/linux/blkdev.h
index 5c8018977efa..9b98173a8184 100644
--- a/trunk/include/linux/blkdev.h
+++ b/trunk/include/linux/blkdev.h
@@ -938,8 +938,6 @@ extern void blk_queue_io_opt(struct request_queue *q, unsigned int opt);
 extern void blk_set_default_limits(struct queue_limits *lim);
 extern int blk_stack_limits(struct queue_limits *t, struct queue_limits *b,
 			    sector_t offset);
-extern int bdev_stack_limits(struct queue_limits *t, struct block_device *bdev,
-			    sector_t offset);
 extern void disk_stack_limits(struct gendisk *disk, struct block_device *bdev,
 			      sector_t offset);
 extern void blk_queue_stack_limits(struct request_queue *t, struct request_queue *b);
@@ -1150,11 +1148,8 @@ static inline int queue_discard_alignment(struct request_queue *q)
 static inline int queue_sector_discard_alignment(struct request_queue *q,
 						 sector_t sector)
 {
-	struct queue_limits *lim = &q->limits;
-	unsigned int alignment = (sector << 9) & (lim->discard_granularity - 1);
-
-	return (lim->discard_granularity + lim->discard_alignment - alignment)
-		& (lim->discard_granularity - 1);
+	return ((sector << 9) - q->limits.discard_alignment)
+		& (q->limits.discard_granularity - 1);
 }
 
 static inline unsigned int queue_discard_zeroes_data(struct request_queue *q)
diff --git a/trunk/include/linux/genhd.h b/trunk/include/linux/genhd.h
index 9717081c75ad..c6c0c41af35f 100644
--- a/trunk/include/linux/genhd.h
+++ b/trunk/include/linux/genhd.h
@@ -256,9 +256,9 @@ extern struct hd_struct *disk_map_sector_rcu(struct gendisk *disk,
 #define part_stat_read(part, field)					\
 ({									\
 	typeof((part)->dkstats->field) res = 0;				\
-	unsigned int _cpu;						\
-	for_each_possible_cpu(_cpu)					\
-		res += per_cpu_ptr((part)->dkstats, _cpu)->field;	\
+	int i;								\
+	for_each_possible_cpu(i)					\
+		res += per_cpu_ptr((part)->dkstats, i)->field;		\
 	res;								\
 })
 
diff --git a/trunk/include/linux/iocontext.h b/trunk/include/linux/iocontext.h
index 78ef023227d4..a63235996309 100644
--- a/trunk/include/linux/iocontext.h
+++ b/trunk/include/linux/iocontext.h
@@ -4,6 +4,32 @@
 #include <linux/radix-tree.h>
 #include <linux/rcupdate.h>
 
+/*
+ * This is the per-process anticipatory I/O scheduler state.
+ */
+struct as_io_context {
+	spinlock_t lock;
+
+	void (*dtor)(struct as_io_context *aic); /* destructor */
+	void (*exit)(struct as_io_context *aic); /* called on task exit */
+
+	unsigned long state;
+	atomic_t nr_queued; /* queued reads & sync writes */
+	atomic_t nr_dispatched; /* number of requests gone to the drivers */
+
+	/* IO History tracking */
+	/* Thinktime */
+	unsigned long last_end_request;
+	unsigned long ttime_total;
+	unsigned long ttime_samples;
+	unsigned long ttime_mean;
+	/* Layout pattern */
+	unsigned int seek_samples;
+	sector_t last_request_pos;
+	u64 seek_total;
+	sector_t seek_mean;
+};
+
 struct cfq_queue;
 struct cfq_io_context {
 	void *key;
@@ -52,6 +78,7 @@ struct io_context {
 	unsigned long last_waited; /* Time last woken after wait for request */
 	int nr_batch_requests;     /* Number of requests left in the batch */
 
+	struct as_io_context *aic;
 	struct radix_tree_root radix_root;
 	struct hlist_head cic_list;
 	void *ioc_data;