Merge branch 'master' of git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux-2.6

Conflicts:

	include/asm-x86/statfs.h

24 files changed, 1896 insertions, 880 deletions

diff --git a/block/Makefile b/block/Makefile
index 208000b0750..bfe73049f93 100644
--- a/block/Makefile
+++ b/block/Makefile
@@ -4,8 +4,8 @@
 
 obj-$(CONFIG_BLOCK) := elevator.o blk-core.o blk-tag.o blk-sysfs.o \
 			blk-barrier.o blk-settings.o blk-ioc.o blk-map.o \
-			blk-exec.o blk-merge.o ioctl.o genhd.o scsi_ioctl.o \
-			cmd-filter.o
+			blk-exec.o blk-merge.o blk-softirq.o blk-timeout.o \
+			ioctl.o genhd.o scsi_ioctl.o cmd-filter.o
 
 obj-$(CONFIG_BLK_DEV_BSG)	+= bsg.o
 obj-$(CONFIG_IOSCHED_NOOP)	+= noop-iosched.o
diff --git a/block/as-iosched.c b/block/as-iosched.c
index cf4eb0eefbb..71f0abb219e 100644
--- a/block/as-iosched.c
+++ b/block/as-iosched.c
@@ -462,7 +462,7 @@ static void as_antic_stop(struct as_data *ad)
 			del_timer(&ad->antic_timer);
 		ad->antic_status = ANTIC_FINISHED;
 		/* see as_work_handler */
-		kblockd_schedule_work(&ad->antic_work);
+		kblockd_schedule_work(ad->q, &ad->antic_work);
 	}
 }
 
@@ -483,7 +483,7 @@ static void as_antic_timeout(unsigned long data)
 		aic = ad->io_context->aic;
 
 		ad->antic_status = ANTIC_FINISHED;
-		kblockd_schedule_work(&ad->antic_work);
+		kblockd_schedule_work(q, &ad->antic_work);
 
 		if (aic->ttime_samples == 0) {
 			/* process anticipated on has exited or timed out*/
@@ -745,6 +745,14 @@ static int as_can_break_anticipation(struct as_data *ad, struct request *rq)
  */
 static int as_can_anticipate(struct as_data *ad, struct request *rq)
 {
+#if 0 /* disable for now, we need to check tag level as well */
+	/*
+	 * SSD device without seek penalty, disable idling
+	 */
+	if (blk_queue_nonrot(ad->q)) axman
+		return 0;
+#endif
+
 	if (!ad->io_context)
 		/*
 		 * Last request submitted was a write
@@ -844,7 +852,7 @@ static void as_completed_request(struct request_queue *q, struct request *rq)
 	if (ad->changed_batch && ad->nr_dispatched == 1) {
 		ad->current_batch_expires = jiffies +
 					ad->batch_expire[ad->batch_data_dir];
-		kblockd_schedule_work(&ad->antic_work);
+		kblockd_schedule_work(q, &ad->antic_work);
 		ad->changed_batch = 0;
 
 		if (ad->batch_data_dir == REQ_SYNC)
diff --git a/block/blk-barrier.c b/block/blk-barrier.c
index a09ead19f9c..5c99ff8d2db 100644
--- a/block/blk-barrier.c
+++ b/block/blk-barrier.c
@@ -293,7 +293,7 @@ int blkdev_issue_flush(struct block_device *bdev, sector_t *error_sector)
 	bio->bi_end_io = bio_end_empty_barrier;
 	bio->bi_private = &wait;
 	bio->bi_bdev = bdev;
-	submit_bio(1 << BIO_RW_BARRIER, bio);
+	submit_bio(WRITE_BARRIER, bio);
 
 	wait_for_completion(&wait);
 
@@ -315,3 +315,73 @@ int blkdev_issue_flush(struct block_device *bdev, sector_t *error_sector)
 	return ret;
 }
 EXPORT_SYMBOL(blkdev_issue_flush);
+
+static void blkdev_discard_end_io(struct bio *bio, int err)
+{
+	if (err) {
+		if (err == -EOPNOTSUPP)
+			set_bit(BIO_EOPNOTSUPP, &bio->bi_flags);
+		clear_bit(BIO_UPTODATE, &bio->bi_flags);
+	}
+
+	bio_put(bio);
+}
+
+/**
+ * blkdev_issue_discard - queue a discard
+ * @bdev:	blockdev to issue discard for
+ * @sector:	start sector
+ * @nr_sects:	number of sectors to discard
+ * @gfp_mask:	memory allocation flags (for bio_alloc)
+ *
+ * Description:
+ *    Issue a discard request for the sectors in question. Does not wait.
+ */
+int blkdev_issue_discard(struct block_device *bdev,
+			 sector_t sector, sector_t nr_sects, gfp_t gfp_mask)
+{
+	struct request_queue *q;
+	struct bio *bio;
+	int ret = 0;
+
+	if (bdev->bd_disk == NULL)
+		return -ENXIO;
+
+	q = bdev_get_queue(bdev);
+	if (!q)
+		return -ENXIO;
+
+	if (!q->prepare_discard_fn)
+		return -EOPNOTSUPP;
+
+	while (nr_sects && !ret) {
+		bio = bio_alloc(gfp_mask, 0);
+		if (!bio)
+			return -ENOMEM;
+
+		bio->bi_end_io = blkdev_discard_end_io;
+		bio->bi_bdev = bdev;
+
+		bio->bi_sector = sector;
+
+		if (nr_sects > q->max_hw_sectors) {
+			bio->bi_size = q->max_hw_sectors << 9;
+			nr_sects -= q->max_hw_sectors;
+			sector += q->max_hw_sectors;
+		} else {
+			bio->bi_size = nr_sects << 9;
+			nr_sects = 0;
+		}
+		bio_get(bio);
+		submit_bio(DISCARD_BARRIER, bio);
+
+		/* Check if it failed immediately */
+		if (bio_flagged(bio, BIO_EOPNOTSUPP))
+			ret = -EOPNOTSUPP;
+		else if (!bio_flagged(bio, BIO_UPTODATE))
+			ret = -EIO;
+		bio_put(bio);
+	}
+	return ret;
+}
+EXPORT_SYMBOL(blkdev_issue_discard);
diff --git a/block/blk-core.c b/block/blk-core.c
index 2cba5ef97b2..2d053b58441 100644
--- a/block/blk-core.c
+++ b/block/blk-core.c
@@ -26,8 +26,6 @@
 #include <linux/swap.h>
 #include <linux/writeback.h>
 #include <linux/task_io_accounting_ops.h>
-#include <linux/interrupt.h>
-#include <linux/cpu.h>
 #include <linux/blktrace_api.h>
 #include <linux/fault-inject.h>
 
@@ -50,27 +48,26 @@ struct kmem_cache *blk_requestq_cachep;
  */
 static struct workqueue_struct *kblockd_workqueue;
 
-static DEFINE_PER_CPU(struct list_head, blk_cpu_done);
-
 static void drive_stat_acct(struct request *rq, int new_io)
 {
 	struct hd_struct *part;
 	int rw = rq_data_dir(rq);
+	int cpu;
 
 	if (!blk_fs_request(rq) || !rq->rq_disk)
 		return;
 
-	part = get_part(rq->rq_disk, rq->sector);
+	cpu = part_stat_lock();
+	part = disk_map_sector_rcu(rq->rq_disk, rq->sector);
+
 	if (!new_io)
-		__all_stat_inc(rq->rq_disk, part, merges[rw], rq->sector);
+		part_stat_inc(cpu, part, merges[rw]);
 	else {
-		disk_round_stats(rq->rq_disk);
-		rq->rq_disk->in_flight++;
-		if (part) {
-			part_round_stats(part);
-			part->in_flight++;
-		}
+		part_round_stats(cpu, part);
+		part_inc_in_flight(part);
 	}
+
+	part_stat_unlock();
 }
 
 void blk_queue_congestion_threshold(struct request_queue *q)
@@ -113,7 +110,8 @@ void blk_rq_init(struct request_queue *q, struct request *rq)
 	memset(rq, 0, sizeof(*rq));
 
 	INIT_LIST_HEAD(&rq->queuelist);
-	INIT_LIST_HEAD(&rq->donelist);
+	INIT_LIST_HEAD(&rq->timeout_list);
+	rq->cpu = -1;
 	rq->q = q;
 	rq->sector = rq->hard_sector = (sector_t) -1;
 	INIT_HLIST_NODE(&rq->hash);
@@ -308,7 +306,7 @@ void blk_unplug_timeout(unsigned long data)
 	blk_add_trace_pdu_int(q, BLK_TA_UNPLUG_TIMER, NULL,
 				q->rq.count[READ] + q->rq.count[WRITE]);
 
-	kblockd_schedule_work(&q->unplug_work);
+	kblockd_schedule_work(q, &q->unplug_work);
 }
 
 void blk_unplug(struct request_queue *q)
@@ -325,6 +323,21 @@ void blk_unplug(struct request_queue *q)
 }
 EXPORT_SYMBOL(blk_unplug);
 
+static void blk_invoke_request_fn(struct request_queue *q)
+{
+	/*
+	 * one level of recursion is ok and is much faster than kicking
+	 * the unplug handling
+	 */
+	if (!queue_flag_test_and_set(QUEUE_FLAG_REENTER, q)) {
+		q->request_fn(q);
+		queue_flag_clear(QUEUE_FLAG_REENTER, q);
+	} else {
+		queue_flag_set(QUEUE_FLAG_PLUGGED, q);
+		kblockd_schedule_work(q, &q->unplug_work);
+	}
+}
+
 /**
  * blk_start_queue - restart a previously stopped queue
  * @q:    The &struct request_queue in question
@@ -339,18 +352,7 @@ void blk_start_queue(struct request_queue *q)
 	WARN_ON(!irqs_disabled());
 
 	queue_flag_clear(QUEUE_FLAG_STOPPED, q);
-
-	/*
-	 * one level of recursion is ok and is much faster than kicking
-	 * the unplug handling
-	 */
-	if (!queue_flag_test_and_set(QUEUE_FLAG_REENTER, q)) {
-		q->request_fn(q);
-		queue_flag_clear(QUEUE_FLAG_REENTER, q);
-	} else {
-		blk_plug_device(q);
-		kblockd_schedule_work(&q->unplug_work);
-	}
+	blk_invoke_request_fn(q);
 }
 EXPORT_SYMBOL(blk_start_queue);
 
@@ -408,15 +410,8 @@ void __blk_run_queue(struct request_queue *q)
 	 * Only recurse once to avoid overrunning the stack, let the unplug
 	 * handling reinvoke the handler shortly if we already got there.
 	 */
-	if (!elv_queue_empty(q)) {
-		if (!queue_flag_test_and_set(QUEUE_FLAG_REENTER, q)) {
-			q->request_fn(q);
-			queue_flag_clear(QUEUE_FLAG_REENTER, q);
-		} else {
-			blk_plug_device(q);
-			kblockd_schedule_work(&q->unplug_work);
-		}
-	}
+	if (!elv_queue_empty(q))
+		blk_invoke_request_fn(q);
 }
 EXPORT_SYMBOL(__blk_run_queue);
 
@@ -441,6 +436,14 @@ void blk_put_queue(struct request_queue *q)
 
 void blk_cleanup_queue(struct request_queue *q)
 {
+	/*
+	 * We know we have process context here, so we can be a little
+	 * cautious and ensure that pending block actions on this device
+	 * are done before moving on. Going into this function, we should
+	 * not have processes doing IO to this device.
+	 */
+	blk_sync_queue(q);
+
 	mutex_lock(&q->sysfs_lock);
 	queue_flag_set_unlocked(QUEUE_FLAG_DEAD, q);
 	mutex_unlock(&q->sysfs_lock);
@@ -496,6 +499,8 @@ struct request_queue *blk_alloc_queue_node(gfp_t gfp_mask, int node_id)
 	}
 
 	init_timer(&q->unplug_timer);
+	setup_timer(&q->timeout, blk_rq_timed_out_timer, (unsigned long) q);
+	INIT_LIST_HEAD(&q->timeout_list);
 
 	kobject_init(&q->kobj, &blk_queue_ktype);
 
@@ -531,7 +536,7 @@ EXPORT_SYMBOL(blk_alloc_queue_node);
  *    request queue; this lock will be taken also from interrupt context, so irq
  *    disabling is needed for it.
  *
- *    Function returns a pointer to the initialized request queue, or NULL if
+ *    Function returns a pointer to the initialized request queue, or %NULL if
  *    it didn't succeed.
  *
  * Note:
@@ -569,7 +574,8 @@ blk_init_queue_node(request_fn_proc *rfn, spinlock_t *lock, int node_id)
 	q->request_fn		= rfn;
 	q->prep_rq_fn		= NULL;
 	q->unplug_fn		= generic_unplug_device;
-	q->queue_flags		= (1 << QUEUE_FLAG_CLUSTER);
+	q->queue_flags		= (1 << QUEUE_FLAG_CLUSTER |
+				   1 << QUEUE_FLAG_STACKABLE);
 	q->queue_lock		= lock;
 
 	blk_queue_segment_boundary(q, 0xffffffff);
@@ -624,10 +630,6 @@ blk_alloc_request(struct request_queue *q, int rw, int priv, gfp_t gfp_mask)
 
 	blk_rq_init(q, rq);
 
-	/*
-	 * first three bits are identical in rq->cmd_flags and bio->bi_rw,
-	 * see bio.h and blkdev.h
-	 */
 	rq->cmd_flags = rw | REQ_ALLOCED;
 
 	if (priv) {
@@ -888,9 +890,11 @@ EXPORT_SYMBOL(blk_get_request);
  */
 void blk_start_queueing(struct request_queue *q)
 {
-	if (!blk_queue_plugged(q))
+	if (!blk_queue_plugged(q)) {
+		if (unlikely(blk_queue_stopped(q)))
+			return;
 		q->request_fn(q);
-	else
+	} else
 		__generic_unplug_device(q);
 }
 EXPORT_SYMBOL(blk_start_queueing);
@@ -907,6 +911,8 @@ EXPORT_SYMBOL(blk_start_queueing);
  */
 void blk_requeue_request(struct request_queue *q, struct request *rq)
 {
+	blk_delete_timer(rq);
+	blk_clear_rq_complete(rq);
 	blk_add_trace_rq(q, rq, BLK_TA_REQUEUE);
 
 	if (blk_rq_tagged(rq))
@@ -917,7 +923,7 @@ void blk_requeue_request(struct request_queue *q, struct request *rq)
 EXPORT_SYMBOL(blk_requeue_request);
 
 /**
- * blk_insert_request - insert a special request in to a request queue
+ * blk_insert_request - insert a special request into a request queue
  * @q:		request queue where request should be inserted
  * @rq:		request to be inserted
  * @at_head:	insert request at head or tail of queue
@@ -927,8 +933,8 @@ EXPORT_SYMBOL(blk_requeue_request);
  *    Many block devices need to execute commands asynchronously, so they don't
  *    block the whole kernel from preemption during request execution.  This is
  *    accomplished normally by inserting aritficial requests tagged as
- *    REQ_SPECIAL in to the corresponding request queue, and letting them be
- *    scheduled for actual execution by the request queue.
+ *    REQ_TYPE_SPECIAL in to the corresponding request queue, and letting them
+ *    be scheduled for actual execution by the request queue.
  *
  *    We have the option of inserting the head or the tail of the queue.
  *    Typically we use the tail for new ioctls and so forth.  We use the head
@@ -982,8 +988,22 @@ static inline void add_request(struct request_queue *q, struct request *req)
 	__elv_add_request(q, req, ELEVATOR_INSERT_SORT, 0);
 }
 
-/*
- * disk_round_stats()	- Round off the performance stats on a struct
+static void part_round_stats_single(int cpu, struct hd_struct *part,
+				    unsigned long now)
+{
+	if (now == part->stamp)
+		return;
+
+	if (part->in_flight) {
+		__part_stat_add(cpu, part, time_in_queue,
+				part->in_flight * (now - part->stamp));
+		__part_stat_add(cpu, part, io_ticks, (now - part->stamp));
+	}
+	part->stamp = now;
+}
+
+/**
+ * part_round_stats()	- Round off the performance stats on a struct
  * disk_stats.
  *
  * The average IO queue length and utilisation statistics are maintained
@@ -997,36 +1017,15 @@ static inline void add_request(struct request_queue *q, struct request *req)
  * /proc/diskstats.  This accounts immediately for all queue usage up to
  * the current jiffies and restarts the counters again.
  */
-void disk_round_stats(struct gendisk *disk)
+void part_round_stats(int cpu, struct hd_struct *part)
 {
 	unsigned long now = jiffies;
 
-	if (now == disk->stamp)
-		return;
-
-	if (disk->in_flight) {
-		__disk_stat_add(disk, time_in_queue,
-				disk->in_flight * (now - disk->stamp));
-		__disk_stat_add(disk, io_ticks, (now - disk->stamp));
-	}
-	disk->stamp = now;
-}
-EXPORT_SYMBOL_GPL(disk_round_stats);
-
-void part_round_stats(struct hd_struct *part)
-{
-	unsigned long now = jiffies;
-
-	if (now == part->stamp)
-		return;
-
-	if (part->in_flight) {
-		__part_stat_add(part, time_in_queue,
-				part->in_flight * (now - part->stamp));
-		__part_stat_add(part, io_ticks, (now - part->stamp));
-	}
-	part->stamp = now;
+	if (part->partno)
+		part_round_stats_single(cpu, &part_to_disk(part)->part0, now);
+	part_round_stats_single(cpu, part, now);
 }
+EXPORT_SYMBOL_GPL(part_round_stats);
 
 /*
  * queue lock must be held
@@ -1070,6 +1069,7 @@ EXPORT_SYMBOL(blk_put_request);
 
 void init_request_from_bio(struct request *req, struct bio *bio)
 {
+	req->cpu = bio->bi_comp_cpu;
 	req->cmd_type = REQ_TYPE_FS;
 
 	/*
@@ -1081,7 +1081,12 @@ void init_request_from_bio(struct request *req, struct bio *bio)
 	/*
 	 * REQ_BARRIER implies no merging, but lets make it explicit
 	 */
-	if (unlikely(bio_barrier(bio)))
+	if (unlikely(bio_discard(bio))) {
+		req->cmd_flags |= REQ_DISCARD;
+		if (bio_barrier(bio))
+			req->cmd_flags |= REQ_SOFTBARRIER;
+		req->q->prepare_discard_fn(req->q, req);
+	} else if (unlikely(bio_barrier(bio)))
 		req->cmd_flags |= (REQ_HARDBARRIER | REQ_NOMERGE);
 
 	if (bio_sync(bio))
@@ -1099,7 +1104,7 @@ void init_request_from_bio(struct request *req, struct bio *bio)
 static int __make_request(struct request_queue *q, struct bio *bio)
 {
 	struct request *req;
-	int el_ret, nr_sectors, barrier, err;
+	int el_ret, nr_sectors, barrier, discard, err;
 	const unsigned short prio = bio_prio(bio);
 	const int sync = bio_sync(bio);
 	int rw_flags;
@@ -1114,7 +1119,14 @@ static int __make_request(struct request_queue *q, struct bio *bio)
 	blk_queue_bounce(q, &bio);
 
 	barrier = bio_barrier(bio);
-	if (unlikely(barrier) && (q->next_ordered == QUEUE_ORDERED_NONE)) {
+	if (unlikely(barrier) && bio_has_data(bio) &&
+	    (q->next_ordered == QUEUE_ORDERED_NONE)) {
+		err = -EOPNOTSUPP;
+		goto end_io;
+	}
+
+	discard = bio_discard(bio);
+	if (unlikely(discard) && !q->prepare_discard_fn) {
 		err = -EOPNOTSUPP;
 		goto end_io;
 	}
@@ -1138,6 +1150,8 @@ static int __make_request(struct request_queue *q, struct bio *bio)
 		req->biotail = bio;
 		req->nr_sectors = req->hard_nr_sectors += nr_sectors;
 		req->ioprio = ioprio_best(req->ioprio, prio);
+		if (!blk_rq_cpu_valid(req))
+			req->cpu = bio->bi_comp_cpu;
 		drive_stat_acct(req, 0);
 		if (!attempt_back_merge(q, req))
 			elv_merged_request(q, req, el_ret);
@@ -1165,6 +1179,8 @@ static int __make_request(struct request_queue *q, struct bio *bio)
 		req->sector = req->hard_sector = bio->bi_sector;
 		req->nr_sectors = req->hard_nr_sectors += nr_sectors;
 		req->ioprio = ioprio_best(req->ioprio, prio);
+		if (!blk_rq_cpu_valid(req))
+			req->cpu = bio->bi_comp_cpu;
 		drive_stat_acct(req, 0);
 		if (!attempt_front_merge(q, req))
 			elv_merged_request(q, req, el_ret);
@@ -1200,13 +1216,15 @@ get_rq:
 	init_request_from_bio(req, bio);
 
 	spin_lock_irq(q->queue_lock);
+	if (test_bit(QUEUE_FLAG_SAME_COMP, &q->queue_flags) ||
+	    bio_flagged(bio, BIO_CPU_AFFINE))
+		req->cpu = blk_cpu_to_group(smp_processor_id());
 	if (elv_queue_empty(q))
 		blk_plug_device(q);
 	add_request(q, req);
 out:
 	if (sync)
 		__generic_unplug_device(q);
-
 	spin_unlock_irq(q->queue_lock);
 	return 0;
 
@@ -1260,8 +1278,9 @@ __setup("fail_make_request=", setup_fail_make_request);
 
 static int should_fail_request(struct bio *bio)
 {
-	if ((bio->bi_bdev->bd_disk->flags & GENHD_FL_FAIL) ||
-	    (bio->bi_bdev->bd_part && bio->bi_bdev->bd_part->make_it_fail))
+	struct hd_struct *part = bio->bi_bdev->bd_part;
+
+	if (part_to_disk(part)->part0.make_it_fail || part->make_it_fail)
 		return should_fail(&fail_make_request, bio->bi_size);
 
 	return 0;
@@ -1314,7 +1333,7 @@ static inline int bio_check_eod(struct bio *bio, unsigned int nr_sectors)
 }
 
 /**
- * generic_make_request: hand a buffer to its device driver for I/O
+ * generic_make_request - hand a buffer to its device driver for I/O
  * @bio:  The bio describing the location in memory and on the device.
  *
  * generic_make_request() is used to make I/O requests of block
@@ -1409,7 +1428,8 @@ end_io:
 
 		if (bio_check_eod(bio, nr_sectors))
 			goto end_io;
-		if (bio_empty_barrier(bio) && !q->prepare_flush_fn) {
+		if ((bio_empty_barrier(bio) && !q->prepare_flush_fn) ||
+		    (bio_discard(bio) && !q->prepare_discard_fn)) {
 			err = -EOPNOTSUPP;
 			goto end_io;
 		}
@@ -1471,13 +1491,13 @@ void generic_make_request(struct bio *bio)
 EXPORT_SYMBOL(generic_make_request);
 
 /**
- * submit_bio: submit a bio to the block device layer for I/O
+ * submit_bio - submit a bio to the block device layer for I/O
  * @rw: whether to %READ or %WRITE, or maybe to %READA (read ahead)
  * @bio: The &struct bio which describes the I/O
  *
  * submit_bio() is very similar in purpose to generic_make_request(), and
  * uses that function to do most of the work. Both are fairly rough
- * interfaces, @bio must be presetup and ready for I/O.
+ * interfaces; @bio must be presetup and ready for I/O.
  *
  */
 void submit_bio(int rw, struct bio *bio)
@@ -1490,11 +1510,7 @@ void submit_bio(int rw, struct bio *bio)
 	 * If it's a regular read/write or a barrier with data attached,
 	 * go through the normal accounting stuff before submission.
 	 */
-	if (!bio_empty_barrier(bio)) {
-
-		BIO_BUG_ON(!bio->bi_size);
-		BIO_BUG_ON(!bio->bi_io_vec);
-
+	if (bio_has_data(bio)) {
 		if (rw & WRITE) {
 			count_vm_events(PGPGOUT, count);
 		} else {
@@ -1517,9 +1533,90 @@ void submit_bio(int rw, struct bio *bio)
 EXPORT_SYMBOL(submit_bio);
 
 /**
+ * blk_rq_check_limits - Helper function to check a request for the queue limit
+ * @q:  the queue
+ * @rq: the request being checked
+ *
+ * Description:
+ *    @rq may have been made based on weaker limitations of upper-level queues
+ *    in request stacking drivers, and it may violate the limitation of @q.
+ *    Since the block layer and the underlying device driver trust @rq
+ *    after it is inserted to @q, it should be checked against @q before
+ *    the insertion using this generic function.
+ *
+ *    This function should also be useful for request stacking drivers
+ *    in some cases below, so export this fuction.
+ *    Request stacking drivers like request-based dm may change the queue
+ *    limits while requests are in the queue (e.g. dm's table swapping).
+ *    Such request stacking drivers should check those requests agaist
+ *    the new queue limits again when they dispatch those requests,
+ *    although such checkings are also done against the old queue limits
+ *    when submitting requests.
+ */
+int blk_rq_check_limits(struct request_queue *q, struct request *rq)
+{
+	if (rq->nr_sectors > q->max_sectors ||
+	    rq->data_len > q->max_hw_sectors << 9) {
+		printk(KERN_ERR "%s: over max size limit.\n", __func__);
+		return -EIO;
+	}
+
+	/*
+	 * queue's settings related to segment counting like q->bounce_pfn
+	 * may differ from that of other stacking queues.
+	 * Recalculate it to check the request correctly on this queue's
+	 * limitation.
+	 */
+	blk_recalc_rq_segments(rq);
+	if (rq->nr_phys_segments > q->max_phys_segments ||
+	    rq->nr_phys_segments > q->max_hw_segments) {
+		printk(KERN_ERR "%s: over max segments limit.\n", __func__);
+		return -EIO;
+	}
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(blk_rq_check_limits);
+
+/**
+ * blk_insert_cloned_request - Helper for stacking drivers to submit a request
+ * @q:  the queue to submit the request
+ * @rq: the request being queued
+ */
+int blk_insert_cloned_request(struct request_queue *q, struct request *rq)
+{
+	unsigned long flags;
+
+	if (blk_rq_check_limits(q, rq))
+		return -EIO;
+
+#ifdef CONFIG_FAIL_MAKE_REQUEST
+	if (rq->rq_disk && rq->rq_disk->part0.make_it_fail &&
+	    should_fail(&fail_make_request, blk_rq_bytes(rq)))
+		return -EIO;
+#endif
+
+	spin_lock_irqsave(q->queue_lock, flags);
+
+	/*
+	 * Submitting request must be dequeued before calling this function
+	 * because it will be linked to another request_queue
+	 */
+	BUG_ON(blk_queued_rq(rq));
+
+	drive_stat_acct(rq, 1);
+	__elv_add_request(q, rq, ELEVATOR_INSERT_BACK, 0);
+
+	spin_unlock_irqrestore(q->queue_lock, flags);
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(blk_insert_cloned_request);
+
+/**
  * __end_that_request_first - end I/O on a request
  * @req:      the request being processed
- * @error:    0 for success, < 0 for error
+ * @error:    %0 for success, < %0 for error
  * @nr_bytes: number of bytes to complete
  *
  * Description:
@@ -1527,8 +1624,8 @@ EXPORT_SYMBOL(submit_bio);
  *     for the next range of segments (if any) in the cluster.
  *
  * Return:
- *     0 - we are done with this request, call end_that_request_last()
- *     1 - still buffers pending for this request
+ *     %0 - we are done with this request, call end_that_request_last()
+ *     %1 - still buffers pending for this request
  **/
 static int __end_that_request_first(struct request *req, int error,
 				    int nr_bytes)
@@ -1539,7 +1636,7 @@ static int __end_that_request_first(struct request *req, int error,
 	blk_add_trace_rq(req->q, req, BLK_TA_COMPLETE);
 
 	/*
-	 * for a REQ_BLOCK_PC request, we want to carry any eventual
+	 * for a REQ_TYPE_BLOCK_PC request, we want to carry any eventual
 	 * sense key with us all the way through
 	 */
 	if (!blk_pc_request(req))
@@ -1552,11 +1649,14 @@ static int __end_that_request_first(struct request *req, int error,
 	}
 
 	if (blk_fs_request(req) && req->rq_disk) {
-		struct hd_struct *part = get_part(req->rq_disk, req->sector);
 		const int rw = rq_data_dir(req);
+		struct hd_struct *part;
+		int cpu;
 
-		all_stat_add(req->rq_disk, part, sectors[rw],
-				nr_bytes >> 9, req->sector);
+		cpu = part_stat_lock();
+		part = disk_map_sector_rcu(req->rq_disk, req->sector);
+		part_stat_add(cpu, part, sectors[rw], nr_bytes >> 9);
+		part_stat_unlock();
 	}
 
 	total_bytes = bio_nbytes = 0;
@@ -1641,88 +1741,14 @@ static int __end_that_request_first(struct request *req, int error,
 }
 
 /*
- * splice the completion data to a local structure and hand off to
- * process_completion_queue() to complete the requests
- */
-static void blk_done_softirq(struct softirq_action *h)
-{
-	struct list_head *cpu_list, local_list;
-
-	local_irq_disable();
-	cpu_list = &__get_cpu_var(blk_cpu_done);
-	list_replace_init(cpu_list, &local_list);
-	local_irq_enable();
-
-	while (!list_empty(&local_list)) {
-		struct request *rq;
-
-		rq = list_entry(local_list.next, struct request, donelist);
-		list_del_init(&rq->donelist);
-		rq->q->softirq_done_fn(rq);
-	}
-}
-
-static int __cpuinit blk_cpu_notify(struct notifier_block *self,
-				    unsigned long action, void *hcpu)
-{
-	/*
-	 * If a CPU goes away, splice its entries to the current CPU
-	 * and trigger a run of the softirq
-	 */
-	if (action == CPU_DEAD || action == CPU_DEAD_FROZEN) {
-		int cpu = (unsigned long) hcpu;
-
-		local_irq_disable();
-		list_splice_init(&per_cpu(blk_cpu_done, cpu),
-				 &__get_cpu_var(blk_cpu_done));
-		raise_softirq_irqoff(BLOCK_SOFTIRQ);
-		local_irq_enable();
-	}
-
-	return NOTIFY_OK;
-}
-
-
-static struct notifier_block blk_cpu_notifier __cpuinitdata = {
-	.notifier_call	= blk_cpu_notify,
-};
-
-/**
- * blk_complete_request - end I/O on a request
- * @req:      the request being processed
- *
- * Description:
- *     Ends all I/O on a request. It does not handle partial completions,
- *     unless the driver actually implements this in its completion callback
- *     through requeueing. The actual completion happens out-of-order,
- *     through a softirq handler. The user must have registered a completion
- *     callback through blk_queue_softirq_done().
- **/
-
-void blk_complete_request(struct request *req)
-{
-	struct list_head *cpu_list;
-	unsigned long flags;
-
-	BUG_ON(!req->q->softirq_done_fn);
-
-	local_irq_save(flags);
-
-	cpu_list = &__get_cpu_var(blk_cpu_done);
-	list_add_tail(&req->donelist, cpu_list);
-	raise_softirq_irqoff(BLOCK_SOFTIRQ);
-
-	local_irq_restore(flags);
-}
-EXPORT_SYMBOL(blk_complete_request);
-
-/*
  * queue lock must be held
  */
 static void end_that_request_last(struct request *req, int error)
 {
 	struct gendisk *disk = req->rq_disk;
 
+	blk_delete_timer(req);
+
 	if (blk_rq_tagged(req))
 		blk_queue_end_tag(req->q, req);
 
@@ -1740,16 +1766,18 @@ static void end_that_request_last(struct request *req, int error)
 	if (disk && blk_fs_request(req) && req != &req->q->bar_rq) {
 		unsigned long duration = jiffies - req->start_time;
 		const int rw = rq_data_dir(req);
-		struct hd_struct *part = get_part(disk, req->sector);
-
-		__all_stat_inc(disk, part, ios[rw], req->sector);
-		__all_stat_add(disk, part, ticks[rw], duration, req->sector);
-		disk_round_stats(disk);
-		disk->in_flight--;
-		if (part) {
-			part_round_stats(part);
-			part->in_flight--;
-		}
+		struct hd_struct *part;
+		int cpu;
+
+		cpu = part_stat_lock();
+		part = disk_map_sector_rcu(disk, req->sector);
+
+		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);
+
+		part_stat_unlock();
 	}
 
 	if (req->end_io)
@@ -1762,17 +1790,6 @@ static void end_that_request_last(struct request *req, int error)
 	}
 }
 
-static inline void __end_request(struct request *rq, int uptodate,
-				 unsigned int nr_bytes)
-{
-	int error = 0;
-
-	if (uptodate <= 0)
-		error = uptodate ? uptodate : -EIO;
-
-	__blk_end_request(rq, error, nr_bytes);
-}
-
 /**
  * blk_rq_bytes - Returns bytes left to complete in the entire request
  * @rq: the request being processed
@@ -1803,74 +1820,57 @@ unsigned int blk_rq_cur_bytes(struct request *rq)
 EXPORT_SYMBOL_GPL(blk_rq_cur_bytes);
 
 /**
- * end_queued_request - end all I/O on a queued request
- * @rq:		the request being processed
- * @uptodate:	error value or 0/1 uptodate flag
- *
- * Description:
- *     Ends all I/O on a request, and removes it from the block layer queues.
- *     Not suitable for normal IO completion, unless the driver still has
- *     the request attached to the block layer.
- *
- **/
-void end_queued_request(struct request *rq, int uptodate)
-{
-	__end_request(rq, uptodate, blk_rq_bytes(rq));
-}
-EXPORT_SYMBOL(end_queued_request);
-
-/**
- * end_dequeued_request - end all I/O on a dequeued request
- * @rq:		the request being processed
- * @uptodate:	error value or 0/1 uptodate flag
- *
- * Description:
- *     Ends all I/O on a request. The request must already have been
- *     dequeued using blkdev_dequeue_request(), as is normally the case
- *     for most drivers.
- *
- **/
-void end_dequeued_request(struct request *rq, int uptodate)
-{
-	__end_request(rq, uptodate, blk_rq_bytes(rq));
-}
-EXPORT_SYMBOL(end_dequeued_request);
-
-
-/**
  * end_request - end I/O on the current segment of the request
  * @req:	the request being processed
- * @uptodate:	error value or 0/1 uptodate flag
+ * @uptodate:	error value or %0/%1 uptodate flag
  *
  * Description:
  *     Ends I/O on the current segment of a request. If that is the only
  *     remaining segment, the request is also completed and freed.
  *
- *     This is a remnant of how older block drivers handled IO completions.
- *     Modern drivers typically end IO on the full request in one go, unless
+ *