Merge branch 'for-4.14/block' of git://git.kernel.dk/linux-block

Pull block layer updates from Jens Axboe:
 "This is the first pull request for 4.14, containing most of the code
  changes. It's a quiet series this round, which I think we needed after
  the churn of the last few series. This contains:

   - Fix for a registration race in loop, from Anton Volkov.

   - Overflow complaint fix from Arnd for DAC960.

   - Series of drbd changes from the usual suspects.

   - Conversion of the stec/skd driver to blk-mq. From Bart.

   - A few BFQ improvements/fixes from Paolo.

   - CFQ improvement from Ritesh, allowing idling for group idle.

   - A few fixes found by Dan's smatch, courtesy of Dan.

   - A warning fixup for a race between changing the IO scheduler and
     device remova. From David Jeffery.

   - A few nbd fixes from Josef.

   - Support for cgroup info in blktrace, from Shaohua.

   - Also from Shaohua, new features in the null_blk driver to allow it
     to actually hold data, among other things.

   - Various corner cases and error handling fixes from Weiping Zhang.

   - Improvements to the IO stats tracking for blk-mq from me. Can
     drastically improve performance for fast devices and/or big
     machines.

   - Series from Christoph removing bi_bdev as being needed for IO
     submission, in preparation for nvme multipathing code.

   - Series from Bart, including various cleanups and fixes for switch
     fall through case complaints"

* 'for-4.14/block' of git://git.kernel.dk/linux-block: (162 commits)
  kernfs: checking for IS_ERR() instead of NULL
  drbd: remove BIOSET_NEED_RESCUER flag from drbd_{md_,}io_bio_set
  drbd: Fix allyesconfig build, fix recent commit
  drbd: switch from kmalloc() to kmalloc_array()
  drbd: abort drbd_start_resync if there is no connection
  drbd: move global variables to drbd namespace and make some static
  drbd: rename "usermode_helper" to "drbd_usermode_helper"
  drbd: fix race between handshake and admin disconnect/down
  drbd: fix potential deadlock when trying to detach during handshake
  drbd: A single dot should be put into a sequence.
  drbd: fix rmmod cleanup, remove _all_ debugfs entries
  drbd: Use setup_timer() instead of init_timer() to simplify the code.
  drbd: fix potential get_ldev/put_ldev refcount imbalance during attach
  drbd: new disk-option disable-write-same
  drbd: Fix resource role for newly created resources in events2
  drbd: mark symbols static where possible
  drbd: Send P_NEG_ACK upon write error in protocol != C
  drbd: add explicit plugging when submitting batches
  drbd: change list_for_each_safe to while(list_first_entry_or_null)
  drbd: introduce drbd_recv_header_maybe_unplug
  ...

26 files changed, 444 insertions, 303 deletions

diff --git a/block/bfq-iosched.c b/block/bfq-iosched.c
index 436b6ca6b175..6a7a26b6cec1 100644
--- a/block/bfq-iosched.c
+++ b/block/bfq-iosched.c
@@ -128,7 +128,7 @@ BFQ_BFQQ_FNS(busy);
 BFQ_BFQQ_FNS(wait_request);
 BFQ_BFQQ_FNS(non_blocking_wait_rq);
 BFQ_BFQQ_FNS(fifo_expire);
-BFQ_BFQQ_FNS(idle_window);
+BFQ_BFQQ_FNS(has_short_ttime);
 BFQ_BFQQ_FNS(sync);
 BFQ_BFQQ_FNS(IO_bound);
 BFQ_BFQQ_FNS(in_large_burst);
@@ -731,10 +731,10 @@ bfq_bfqq_resume_state(struct bfq_queue *bfqq, struct bfq_data *bfqd,
 	unsigned int old_wr_coeff = bfqq->wr_coeff;
 	bool busy = bfq_already_existing && bfq_bfqq_busy(bfqq);
 
-	if (bic->saved_idle_window)
-		bfq_mark_bfqq_idle_window(bfqq);
+	if (bic->saved_has_short_ttime)
+		bfq_mark_bfqq_has_short_ttime(bfqq);
 	else
-		bfq_clear_bfqq_idle_window(bfqq);
+		bfq_clear_bfqq_has_short_ttime(bfqq);
 
 	if (bic->saved_IO_bound)
 		bfq_mark_bfqq_IO_bound(bfqq);
@@ -2012,7 +2012,7 @@ static void bfq_bfqq_save_state(struct bfq_queue *bfqq)
 		return;
 
 	bic->saved_ttime = bfqq->ttime;
-	bic->saved_idle_window = bfq_bfqq_idle_window(bfqq);
+	bic->saved_has_short_ttime = bfq_bfqq_has_short_ttime(bfqq);
 	bic->saved_IO_bound = bfq_bfqq_IO_bound(bfqq);
 	bic->saved_in_large_burst = bfq_bfqq_in_large_burst(bfqq);
 	bic->was_in_burst_list = !hlist_unhashed(&bfqq->burst_list_node);
@@ -3038,8 +3038,8 @@ void bfq_bfqq_expire(struct bfq_data *bfqd,
 	}
 
 	bfq_log_bfqq(bfqd, bfqq,
-		"expire (%d, slow %d, num_disp %d, idle_win %d)", reason,
-		slow, bfqq->dispatched, bfq_bfqq_idle_window(bfqq));
+		"expire (%d, slow %d, num_disp %d, short_ttime %d)", reason,
+		slow, bfqq->dispatched, bfq_bfqq_has_short_ttime(bfqq));
 
 	/*
 	 * Increase, decrease or leave budget unchanged according to
@@ -3114,7 +3114,10 @@ static bool bfq_may_expire_for_budg_timeout(struct bfq_queue *bfqq)
 static bool bfq_bfqq_may_idle(struct bfq_queue *bfqq)
 {
 	struct bfq_data *bfqd = bfqq->bfqd;
-	bool idling_boosts_thr, idling_boosts_thr_without_issues,
+	bool rot_without_queueing =
+		!blk_queue_nonrot(bfqd->queue) && !bfqd->hw_tag,
+		bfqq_sequential_and_IO_bound,
+		idling_boosts_thr, idling_boosts_thr_without_issues,
 		idling_needed_for_service_guarantees,
 		asymmetric_scenario;
 
@@ -3122,27 +3125,45 @@ static bool bfq_bfqq_may_idle(struct bfq_queue *bfqq)
 		return true;
 
 	/*
+	 * Idling is performed only if slice_idle > 0. In addition, we
+	 * do not idle if
+	 * (a) bfqq is async
+	 * (b) bfqq is in the idle io prio class: in this case we do
+	 * not idle because we want to minimize the bandwidth that
+	 * queues in this class can steal to higher-priority queues
+	 */
+	if (bfqd->bfq_slice_idle == 0 || !bfq_bfqq_sync(bfqq) ||
+	    bfq_class_idle(bfqq))
+		return false;
+
+	bfqq_sequential_and_IO_bound = !BFQQ_SEEKY(bfqq) &&
+		bfq_bfqq_IO_bound(bfqq) && bfq_bfqq_has_short_ttime(bfqq);
+
+	/*
 	 * The next variable takes into account the cases where idling
 	 * boosts the throughput.
 	 *
 	 * The value of the variable is computed considering, first, that
 	 * idling is virtually always beneficial for the throughput if:
-	 * (a) the device is not NCQ-capable, or
-	 * (b) regardless of the presence of NCQ, the device is rotational
-	 *     and the request pattern for bfqq is I/O-bound and sequential.
+	 * (a) the device is not NCQ-capable and rotational, or
+	 * (b) regardless of the presence of NCQ, the device is rotational and
+	 *     the request pattern for bfqq is I/O-bound and sequential, or
+	 * (c) regardless of whether it is rotational, the device is
+	 *     not NCQ-capable and the request pattern for bfqq is
+	 *     I/O-bound and sequential.
 	 *
 	 * Secondly, and in contrast to the above item (b), idling an
 	 * NCQ-capable flash-based device would not boost the
 	 * throughput even with sequential I/O; rather it would lower
 	 * the throughput in proportion to how fast the device
 	 * is. Accordingly, the next variable is true if any of the
-	 * above conditions (a) and (b) is true, and, in particular,
-	 * happens to be false if bfqd is an NCQ-capable flash-based
-	 * device.
+	 * above conditions (a), (b) or (c) is true, and, in
+	 * particular, happens to be false if bfqd is an NCQ-capable
+	 * flash-based device.
 	 */
-	idling_boosts_thr = !bfqd->hw_tag ||
-		(!blk_queue_nonrot(bfqd->queue) && bfq_bfqq_IO_bound(bfqq) &&
-		 bfq_bfqq_idle_window(bfqq));
+	idling_boosts_thr = rot_without_queueing ||
+		((!blk_queue_nonrot(bfqd->queue) || !bfqd->hw_tag) &&
+		 bfqq_sequential_and_IO_bound);
 
 	/*
 	 * The value of the next variable,
@@ -3313,16 +3334,13 @@ static bool bfq_bfqq_may_idle(struct bfq_queue *bfqq)
 		asymmetric_scenario && !bfq_bfqq_in_large_burst(bfqq);
 
 	/*
-	 * We have now all the components we need to compute the return
-	 * value of the function, which is true only if both the following
-	 * conditions hold:
-	 * 1) bfqq is sync, because idling make sense only for sync queues;
-	 * 2) idling either boosts the throughput (without issues), or
-	 *    is necessary to preserve service guarantees.
+	 * We have now all the components we need to compute the
+	 * return value of the function, which is true only if idling
+	 * either boosts the throughput (without issues), or is
+	 * necessary to preserve service guarantees.
 	 */
-	return bfq_bfqq_sync(bfqq) &&
-		(idling_boosts_thr_without_issues ||
-		 idling_needed_for_service_guarantees);
+	return idling_boosts_thr_without_issues ||
+		idling_needed_for_service_guarantees;
 }
 
 /*
@@ -3338,10 +3356,7 @@ static bool bfq_bfqq_may_idle(struct bfq_queue *bfqq)
  */
 static bool bfq_bfqq_must_idle(struct bfq_queue *bfqq)
 {
-	struct bfq_data *bfqd = bfqq->bfqd;
-
-	return RB_EMPTY_ROOT(&bfqq->sort_list) && bfqd->bfq_slice_idle != 0 &&
-	       bfq_bfqq_may_idle(bfqq);
+	return RB_EMPTY_ROOT(&bfqq->sort_list) && bfq_bfqq_may_idle(bfqq);
 }
 
 /*
@@ -3783,7 +3798,6 @@ bfq_set_next_ioprio_data(struct bfq_queue *bfqq, struct bfq_io_cq *bic)
 	case IOPRIO_CLASS_IDLE:
 		bfqq->new_ioprio_class = IOPRIO_CLASS_IDLE;
 		bfqq->new_ioprio = 7;
-		bfq_clear_bfqq_idle_window(bfqq);
 		break;
 	}
 
@@ -3843,8 +3857,14 @@ static void bfq_init_bfqq(struct bfq_data *bfqd, struct bfq_queue *bfqq,
 		bfq_set_next_ioprio_data(bfqq, bic);
 
 	if (is_sync) {
+		/*
+		 * No need to mark as has_short_ttime if in
+		 * idle_class, because no device idling is performed
+		 * for queues in idle class
+		 */
 		if (!bfq_class_idle(bfqq))
-			bfq_mark_bfqq_idle_window(bfqq);
+			/* tentatively mark as has_short_ttime */
+			bfq_mark_bfqq_has_short_ttime(bfqq);
 		bfq_mark_bfqq_sync(bfqq);
 		bfq_mark_bfqq_just_created(bfqq);
 	} else
@@ -3985,18 +4005,19 @@ bfq_update_io_seektime(struct bfq_data *bfqd, struct bfq_queue *bfqq,
 		 blk_rq_sectors(rq) < BFQQ_SECT_THR_NONROT);
 }
 
-/*
- * Disable idle window if the process thinks too long or seeks so much that
- * it doesn't matter.
- */
-static void bfq_update_idle_window(struct bfq_data *bfqd,
-				   struct bfq_queue *bfqq,
-				   struct bfq_io_cq *bic)
+static void bfq_update_has_short_ttime(struct bfq_data *bfqd,
+				       struct bfq_queue *bfqq,
+				       struct bfq_io_cq *bic)
 {
-	int enable_idle;
+	bool has_short_ttime = true;
 
-	/* Don't idle for async or idle io prio class. */
-	if (!bfq_bfqq_sync(bfqq) || bfq_class_idle(bfqq))
+	/*
+	 * No need to update has_short_ttime if bfqq is async or in
+	 * idle io prio class, or if bfq_slice_idle is zero, because
+	 * no device idling is performed for bfqq in this case.
+	 */
+	if (!bfq_bfqq_sync(bfqq) || bfq_class_idle(bfqq) ||
+	    bfqd->bfq_slice_idle == 0)
 		return;
 
 	/* Idle window just restored, statistics are meaningless. */
@@ -4004,27 +4025,22 @@ static void bfq_update_idle_window(struct bfq_data *bfqd,
 				     bfqd->bfq_wr_min_idle_time))
 		return;
 
-	enable_idle = bfq_bfqq_idle_window(bfqq);
-
+	/* Think time is infinite if no process is linked to
+	 * bfqq. Otherwise check average think time to
+	 * decide whether to mark as has_short_ttime
+	 */
 	if (atomic_read(&bic->icq.ioc->active_ref) == 0 ||
-	    bfqd->bfq_slice_idle == 0 ||
-		(bfqd->hw_tag && BFQQ_SEEKY(bfqq) &&
-			bfqq->wr_coeff == 1))
-		enable_idle = 0;
-	else if (bfq_sample_valid(bfqq->ttime.ttime_samples)) {
-		if (bfqq->ttime.ttime_mean > bfqd->bfq_slice_idle &&
-			bfqq->wr_coeff == 1)
-			enable_idle = 0;
-		else
-			enable_idle = 1;
-	}
-	bfq_log_bfqq(bfqd, bfqq, "update_idle_window: enable_idle %d",
-		enable_idle);
+	    (bfq_sample_valid(bfqq->ttime.ttime_samples) &&
+	     bfqq->ttime.ttime_mean > bfqd->bfq_slice_idle))
+		has_short_ttime = false;
 
-	if (enable_idle)
-		bfq_mark_bfqq_idle_window(bfqq);
+	bfq_log_bfqq(bfqd, bfqq, "update_has_short_ttime: has_short_ttime %d",
+		     has_short_ttime);
+
+	if (has_short_ttime)
+		bfq_mark_bfqq_has_short_ttime(bfqq);
 	else
-		bfq_clear_bfqq_idle_window(bfqq);
+		bfq_clear_bfqq_has_short_ttime(bfqq);
 }
 
 /*
@@ -4040,14 +4056,12 @@ static void bfq_rq_enqueued(struct bfq_data *bfqd, struct bfq_queue *bfqq,
 		bfqq->meta_pending++;
 
 	bfq_update_io_thinktime(bfqd, bfqq);
+	bfq_update_has_short_ttime(bfqd, bfqq, bic);
 	bfq_update_io_seektime(bfqd, bfqq, rq);
-	if (bfqq->entity.service > bfq_max_budget(bfqd) / 8 ||
-	    !BFQQ_SEEKY(bfqq))
-		bfq_update_idle_window(bfqd, bfqq, bic);
 
 	bfq_log_bfqq(bfqd, bfqq,
-		     "rq_enqueued: idle_window=%d (seeky %d)",
-		     bfq_bfqq_idle_window(bfqq), BFQQ_SEEKY(bfqq));
+		     "rq_enqueued: has_short_ttime=%d (seeky %d)",
+		     bfq_bfqq_has_short_ttime(bfqq), BFQQ_SEEKY(bfqq));
 
 	bfqq->last_request_pos = blk_rq_pos(rq) + blk_rq_sectors(rq);
 
@@ -4787,16 +4801,13 @@ static ssize_t bfq_var_show(unsigned int var, char *page)
 	return sprintf(page, "%u\n", var);
 }
 
-static ssize_t bfq_var_store(unsigned long *var, const char *page,
-			     size_t count)
+static void bfq_var_store(unsigned long *var, const char *page)
 {
 	unsigned long new_val;
 	int ret = kstrtoul(page, 10, &new_val);
 
 	if (ret == 0)
 		*var = new_val;
-
-	return count;
 }
 
 #define SHOW_FUNCTION(__FUNC, __VAR, __CONV)				\
@@ -4838,7 +4849,7 @@ __FUNC(struct elevator_queue *e, const char *page, size_t count)	\
 {									\
 	struct bfq_data *bfqd = e->elevator_data;			\
 	unsigned long uninitialized_var(__data);			\
-	int ret = bfq_var_store(&__data, (page), count);		\
+	bfq_var_store(&__data, (page));					\
 	if (__data < (MIN))						\
 		__data = (MIN);						\
 	else if (__data > (MAX))					\
@@ -4849,7 +4860,7 @@ __FUNC(struct elevator_queue *e, const char *page, size_t count)	\
 		*(__PTR) = (u64)__data * NSEC_PER_MSEC;			\
 	else								\
 		*(__PTR) = __data;					\
-	return ret;							\
+	return count;							\
 }
 STORE_FUNCTION(bfq_fifo_expire_sync_store, &bfqd->bfq_fifo_expire[1], 1,
 		INT_MAX, 2);
@@ -4866,13 +4877,13 @@ static ssize_t __FUNC(struct elevator_queue *e, const char *page, size_t count)\
 {									\
 	struct bfq_data *bfqd = e->elevator_data;			\
 	unsigned long uninitialized_var(__data);			\
-	int ret = bfq_var_store(&__data, (page), count);		\
+	bfq_var_store(&__data, (page));					\
 	if (__data < (MIN))						\
 		__data = (MIN);						\
 	else if (__data > (MAX))					\
 		__data = (MAX);						\
 	*(__PTR) = (u64)__data * NSEC_PER_USEC;				\
-	return ret;							\
+	return count;							\
 }
 USEC_STORE_FUNCTION(bfq_slice_idle_us_store, &bfqd->bfq_slice_idle, 0,
 		    UINT_MAX);
@@ -4883,7 +4894,8 @@ static ssize_t bfq_max_budget_store(struct elevator_queue *e,
 {
 	struct bfq_data *bfqd = e->elevator_data;
 	unsigned long uninitialized_var(__data);
-	int ret = bfq_var_store(&__data, (page), count);
+
+	bfq_var_store(&__data, (page));
 
 	if (__data == 0)
 		bfqd->bfq_max_budget = bfq_calc_max_budget(bfqd);
@@ -4895,7 +4907,7 @@ static ssize_t bfq_max_budget_store(struct elevator_queue *e,
 
 	bfqd->bfq_user_max_budget = __data;
 
-	return ret;
+	return count;
 }
 
 /*
@@ -4907,7 +4919,8 @@ static ssize_t bfq_timeout_sync_store(struct elevator_queue *e,
 {
 	struct bfq_data *bfqd = e->elevator_data;
 	unsigned long uninitialized_var(__data);
-	int ret = bfq_var_store(&__data, (page), count);
+
+	bfq_var_store(&__data, (page));
 
 	if (__data < 1)
 		__data = 1;
@@ -4918,7 +4931,7 @@ static ssize_t bfq_timeout_sync_store(struct elevator_queue *e,
 	if (bfqd->bfq_user_max_budget == 0)
 		bfqd->bfq_max_budget = bfq_calc_max_budget(bfqd);
 
-	return ret;
+	return count;
 }
 
 static ssize_t bfq_strict_guarantees_store(struct elevator_queue *e,
@@ -4926,7 +4939,8 @@ static ssize_t bfq_strict_guarantees_store(struct elevator_queue *e,
 {
 	struct bfq_data *bfqd = e->elevator_data;
 	unsigned long uninitialized_var(__data);
-	int ret = bfq_var_store(&__data, (page), count);
+
+	bfq_var_store(&__data, (page));
 
 	if (__data > 1)
 		__data = 1;
@@ -4936,7 +4950,7 @@ static ssize_t bfq_strict_guarantees_store(struct elevator_queue *e,
 
 	bfqd->strict_guarantees = __data;
 
-	return ret;
+	return count;
 }
 
 static ssize_t bfq_low_latency_store(struct elevator_queue *e,
@@ -4944,7 +4958,8 @@ static ssize_t bfq_low_latency_store(struct elevator_queue *e,
 {
 	struct bfq_data *bfqd = e->elevator_data;
 	unsigned long uninitialized_var(__data);
-	int ret = bfq_var_store(&__data, (page), count);
+
+	bfq_var_store(&__data, (page));
 
 	if (__data > 1)
 		__data = 1;
@@ -4952,7 +4967,7 @@ static ssize_t bfq_low_latency_store(struct elevator_queue *e,
 		bfq_end_wr(bfqd);
 	bfqd->low_latency = __data;
 
-	return ret;
+	return count;
 }
 
 #define BFQ_ATTR(name) \
@@ -4998,6 +5013,7 @@ static struct elevator_type iosched_bfq_mq = {
 	.elevator_name =	"bfq",
 	.elevator_owner =	THIS_MODULE,
 };
+MODULE_ALIAS("bfq-iosched");
 
 static int __init bfq_init(void)
 {
@@ -5048,10 +5064,12 @@ static int __init bfq_init(void)
 
 	ret = elv_register(&iosched_bfq_mq);
 	if (ret)
-		goto err_pol_unreg;
+		goto slab_kill;
 
 	return 0;
 
+slab_kill:
+	bfq_slab_kill();
 err_pol_unreg:
 #ifdef CONFIG_BFQ_GROUP_IOSCHED
 	blkcg_policy_unregister(&blkcg_policy_bfq);
diff --git a/block/bfq-iosched.h b/block/bfq-iosched.h
index 859f0a8c97c8..cc4ea8574483 100644
--- a/block/bfq-iosched.h
+++ b/block/bfq-iosched.h
@@ -360,11 +360,11 @@ struct bfq_io_cq {
 	uint64_t blkcg_serial_nr; /* the current blkcg serial */
 #endif
 	/*
-	 * Snapshot of the idle window before merging; taken to
-	 * remember this value while the queue is merged, so as to be
-	 * able to restore it in case of split.
+	 * Snapshot of the has_short_time flag before merging; taken
+	 * to remember its value while the queue is merged, so as to
+	 * be able to restore it in case of split.
 	 */
-	bool saved_idle_window;
+	bool saved_has_short_ttime;
 	/*
 	 * Same purpose as the previous two fields for the I/O bound
 	 * classification of a queue.
@@ -638,7 +638,7 @@ enum bfqq_state_flags {
 				     * without idling the device
 				     */
 	BFQQF_fifo_expire,	/* FIFO checked in this slice */
-	BFQQF_idle_window,	/* slice idling enabled */
+	BFQQF_has_short_ttime,	/* queue has a short think time */
 	BFQQF_sync,		/* synchronous queue */
 	BFQQF_IO_bound,		/*
 				 * bfqq has timed-out at least once
@@ -667,7 +667,7 @@ BFQ_BFQQ_FNS(busy);
 BFQ_BFQQ_FNS(wait_request);
 BFQ_BFQQ_FNS(non_blocking_wait_rq);
 BFQ_BFQQ_FNS(fifo_expire);
-BFQ_BFQQ_FNS(idle_window);
+BFQ_BFQQ_FNS(has_short_ttime);
 BFQ_BFQQ_FNS(sync);
 BFQ_BFQQ_FNS(IO_bound);
 BFQ_BFQQ_FNS(in_large_burst);
@@ -929,13 +929,16 @@ void bfq_add_bfqq_busy(struct bfq_data *bfqd, struct bfq_queue *bfqq);
 struct bfq_group *bfqq_group(struct bfq_queue *bfqq);
 
 #define bfq_log_bfqq(bfqd, bfqq, fmt, args...)	do {			\
-	blk_add_trace_msg((bfqd)->queue, "bfq%d%c %s " fmt, (bfqq)->pid,\
-			bfq_bfqq_sync((bfqq)) ? 'S' : 'A',		\
-			bfqq_group(bfqq)->blkg_path, ##args);		\
+	blk_add_cgroup_trace_msg((bfqd)->queue,				\
+			bfqg_to_blkg(bfqq_group(bfqq))->blkcg,		\
+			"bfq%d%c " fmt, (bfqq)->pid,			\
+			bfq_bfqq_sync((bfqq)) ? 'S' : 'A', ##args);	\
 } while (0)
 
-#define bfq_log_bfqg(bfqd, bfqg, fmt, args...)	\
-	blk_add_trace_msg((bfqd)->queue, "%s " fmt, (bfqg)->blkg_path, ##args)
+#define bfq_log_bfqg(bfqd, bfqg, fmt, args...)	do {			\
+	blk_add_cgroup_trace_msg((bfqd)->queue,				\
+		bfqg_to_blkg(bfqg)->blkcg, fmt, ##args);		\
+} while (0)
 
 #else /* CONFIG_BFQ_GROUP_IOSCHED */
 
diff --git a/block/bio-integrity.c b/block/bio-integrity.c
index 9b1ea478577b..5df32907ff3b 100644
--- a/block/bio-integrity.c
+++ b/block/bio-integrity.c
@@ -146,7 +146,7 @@ int bio_integrity_add_page(struct bio *bio, struct page *page,
 	iv = bip->bip_vec + bip->bip_vcnt;
 
 	if (bip->bip_vcnt &&
-	    bvec_gap_to_prev(bdev_get_queue(bio->bi_bdev),
+	    bvec_gap_to_prev(bio->bi_disk->queue,
 			     &bip->bip_vec[bip->bip_vcnt - 1], offset))
 		return 0;
 
@@ -190,7 +190,7 @@ static inline unsigned int bio_integrity_bytes(struct blk_integrity *bi,
 static blk_status_t bio_integrity_process(struct bio *bio,
 		struct bvec_iter *proc_iter, integrity_processing_fn *proc_fn)
 {
-	struct blk_integrity *bi = bdev_get_integrity(bio->bi_bdev);
+	struct blk_integrity *bi = blk_get_integrity(bio->bi_disk);
 	struct blk_integrity_iter iter;
 	struct bvec_iter bviter;
 	struct bio_vec bv;
@@ -199,7 +199,7 @@ static blk_status_t bio_integrity_process(struct bio *bio,
 	void *prot_buf = page_address(bip->bip_vec->bv_page) +
 		bip->bip_vec->bv_offset;
 
-	iter.disk_name = bio->bi_bdev->bd_disk->disk_name;
+	iter.disk_name = bio->bi_disk->disk_name;
 	iter.interval = 1 << bi->interval_exp;
 	iter.seed = proc_iter->bi_sector;
 	iter.prot_buf = prot_buf;
@@ -236,8 +236,8 @@ static blk_status_t bio_integrity_process(struct bio *bio,
 bool bio_integrity_prep(struct bio *bio)
 {
 	struct bio_integrity_payload *bip;
-	struct blk_integrity *bi;
-	struct request_queue *q;
+	struct blk_integrity *bi = blk_get_integrity(bio->bi_disk);
+	struct request_queue *q = bio->bi_disk->queue;
 	void *buf;
 	unsigned long start, end;
 	unsigned int len, nr_pages;
@@ -245,8 +245,9 @@ bool bio_integrity_prep(struct bio *bio)
 	unsigned int intervals;
 	blk_status_t status;
 
-	bi = bdev_get_integrity(bio->bi_bdev);
-	q = bdev_get_queue(bio->bi_bdev);
+	if (!bi)
+		return true;
+
 	if (bio_op(bio) != REQ_OP_READ && bio_op(bio) != REQ_OP_WRITE)
 		return true;
 
@@ -257,9 +258,6 @@ bool bio_integrity_prep(struct bio *bio)
 	if (bio_integrity(bio))
 		return true;
 
-	if (bi == NULL)
-		return true;
-
 	if (bio_data_dir(bio) == READ) {
 		if (!bi->profile->verify_fn ||
 		    !(bi->flags & BLK_INTEGRITY_VERIFY))
@@ -354,7 +352,7 @@ static void bio_integrity_verify_fn(struct work_struct *work)
 	struct bio_integrity_payload *bip =
 		container_of(work, struct bio_integrity_payload, bip_work);
 	struct bio *bio = bip->bip_bio;
-	struct blk_integrity *bi = bdev_get_integrity(bio->bi_bdev);
+	struct blk_integrity *bi = blk_get_integrity(bio->bi_disk);
 	struct bvec_iter iter = bio->bi_iter;
 
 	/*
@@ -387,7 +385,7 @@ static void bio_integrity_verify_fn(struct work_struct *work)
  */
 bool __bio_integrity_endio(struct bio *bio)
 {
-	struct blk_integrity *bi = bdev_get_integrity(bio->bi_bdev);
+	struct blk_integrity *bi = blk_get_integrity(bio->bi_disk);
 	struct bio_integrity_payload *bip = bio_integrity(bio);
 
 	if (bio_op(bio) == REQ_OP_READ && !bio->bi_status &&
@@ -413,7 +411,7 @@ bool __bio_integrity_endio(struct bio *bio)
 void bio_integrity_advance(struct bio *bio, unsigned int bytes_done)
 {
 	struct bio_integrity_payload *bip = bio_integrity(bio);
-	struct blk_integrity *bi = bdev_get_integrity(bio->bi_bdev);
+	struct blk_integrity *bi = blk_get_integrity(bio->bi_disk);
 	unsigned bytes = bio_integrity_bytes(bi, bytes_done >> 9);
 
 	bip->bip_iter.bi_sector += bytes_done >> 9;
@@ -430,7 +428,7 @@ EXPORT_SYMBOL(bio_integrity_advance);
 void bio_integrity_trim(struct bio *bio)
 {
 	struct bio_integrity_payload *bip = bio_integrity(bio);
-	struct blk_integrity *bi = bdev_get_integrity(bio->bi_bdev);
+	struct blk_integrity *bi = blk_get_integrity(bio->bi_disk);
 
 	bip->bip_iter.bi_size = bio_integrity_bytes(bi, bio_sectors(bio));
 }
diff --git a/block/bio.c b/block/bio.c
index 9a63597aaacc..6745759028da 100644
--- a/block/bio.c
+++ b/block/bio.c
@@ -593,10 +593,10 @@ void __bio_clone_fast(struct bio *bio, struct bio *bio_src)
 	BUG_ON(bio->bi_pool && BVEC_POOL_IDX(bio));
 
 	/*
-	 * most users will be overriding ->bi_bdev with a new target,
+	 * most users will be overriding ->bi_disk with a new target,
 	 * so we don't set nor calculate new physical/hw segment counts here
 	 */
-	bio->bi_bdev = bio_src->bi_bdev;
+	bio->bi_disk = bio_src->bi_disk;
 	bio_set_flag(bio, BIO_CLONED);
 	bio->bi_opf = bio_src->bi_opf;
 	bio->bi_write_hint = bio_src->bi_write_hint;
@@ -681,7 +681,7 @@ struct bio *bio_clone_bioset(struct bio *bio_src, gfp_t gfp_mask,
 	bio = bio_alloc_bioset(gfp_mask, bio_segments(bio_src), bs);
 	if (!bio)
 		return NULL;
-	bio->bi_bdev		= bio_src->bi_bdev;
+	bio->bi_disk		= bio_src->bi_disk;
 	bio->bi_opf		= bio_src->bi_opf;
 	bio->bi_write_hint	= bio_src->bi_write_hint;
 	bio->bi_iter.bi_sector	= bio_src->bi_iter.bi_sector;
@@ -936,6 +936,10 @@ static void submit_bio_wait_endio(struct bio *bio)
  *
  * Simple wrapper around submit_bio(). Returns 0 on success, or the error from
  * bio_endio() on failure.
+ *
+ * WARNING: Unlike to how submit_bio() is usually used, this function does not
+ * result in bio reference to be consumed. The caller must drop the reference
+ * on his own.
  */
 int submit_bio_wait(struct bio *bio)
 {
@@ -1732,29 +1736,29 @@ void bio_check_pages_dirty(struct bio *bio)
 	}
 }
 
-void generic_start_io_acct(int rw, unsigned long sectors,
-			   struct hd_struct *part)
+void generic_start_io_acct(struct request_queue *q, int rw,
+			   unsigned long sectors, struct hd_struct *part)
 {
 	int cpu = part_stat_lock();
 
-	part_round_stats(cpu, part);
+	part_round_stats(q, cpu, part);
 	part_stat_inc(cpu, part, ios[rw]);
 	part_stat_add(cpu, part, sectors[rw], sectors);
-	part_inc_in_flight(part, rw);
+	part_inc_in_flight(q, part, rw);
 
 	part_stat_unlock();
 }
 EXPORT_SYMBOL(generic_start_io_acct);
 
-void generic_end_io_acct(int rw, struct hd_struct *part,
-			 unsigned long start_time)
+void generic_end_io_acct(struct request_queue *q, int rw,
+			 struct hd_struct *part, unsigned long start_time)
 {
 	unsigned long duration = jiffies - start_time;
 	int cpu = part_stat_lock();
 
 	part_stat_add(cpu, part, ticks[rw], duration);
-	part_round_stats(cpu, part);
-	part_dec_in_flight(part, rw);
+	part_round_stats(q, cpu, part);
+	part_dec_in_flight(q, part, rw);
 
 	part_stat_unlock();
 }
@@ -1826,8 +1830,8 @@ again:
 		goto again;
 	}
 
-	if (bio->bi_bdev && bio_flagged(bio, BIO_TRACE_COMPLETION)) {
-		trace_block_bio_complete(bdev_get_queue(bio->bi_bdev), bio,
+	if (bio->bi_disk && bio_flagged(bio, BIO_TRACE_COMPLETION)) {
+		trace_block_bio_complete(bio->bi_disk->queue, bio,
 					 blk_status_to_errno(bio->bi_status));
 		bio_clear_flag(bio, BIO_TRACE_COMPLETION);
 	}
diff --git a/block/blk-cgroup.c b/block/blk-cgroup.c
index 0480892e97e5..d3f56baee936 100644
--- a/block/blk-cgroup.c
+++ b/block/blk-cgroup.c
@@ -1067,7 +1067,7 @@ blkcg_css_alloc(struct cgroup_subsys_state *parent_css)
 		blkcg = kzalloc(sizeof(*blkcg), GFP_KERNEL);
 		if (!blkcg) {
 			ret = ERR_PTR(-ENOMEM);
-			goto free_blkcg;
+			goto unlock;
 		}
 	}
 
@@ -1111,8 +1111,10 @@ free_pd_blkcg:
 	for (i--; i >= 0; i--)
 		if (blkcg->cpd[i])
 			blkcg_policy[i]->cpd_free_fn(blkcg->cpd[i]);
-free_blkcg:
-	kfree(blkcg);
+
+	if (blkcg != &blkcg_root)
+		kfree(blkcg);
+unlock:
 	mutex_unlock(&blkcg_pol_mutex);
 	return ret;
 }
diff --git a/block/blk-core.c b/block/blk-core.c
index dbecbf4a64e0..d709c0e3a2ac 100644
--- a/block/blk-core.c
+++ b/block/blk-core.c
@@ -280,7 +280,7 @@ EXPORT_SYMBOL(blk_start_queue_async);
 void blk_start_queue(struct request_queue *q)
 {
 	lockdep_assert_held(q->queue_lock);
-	WARN_ON(!irqs_disabled());
+	WARN_ON(!in_interrupt() && !irqs_disabled());
 	WARN_ON_ONCE(q->mq_ops);
 
 	queue_flag_clear(QUEUE_FLAG_STOPPED, q);
@@ -1469,15 +1469,10 @@ static void add_acct_request(struct request_queue *q, struct request *rq,
 	__elv_add_request(q, rq, where);
 }
 
-static void part_round_stats_single(int cpu, struct hd_struct *part,
-				    unsigned long now)
+static void part_round_stats_single(struct request_queue *q, int cpu,
+				    struct hd_struct *part, unsigned long now,
+				    unsigned int inflight)
 {
-	int inflight;
-
-	if (now == part->stamp)
-		return;
-
-	inflight = part_in_flight(part);
 	if (inflight) {
 		__part_stat_add(cpu, part, time_in_queue,
 				inflight * (now - part->stamp));
@@ -1488,6 +1483,7 @@ static void part_round_stats_single(int cpu, struct hd_struct *part,
 
 /**
  * part_round_stats() - Round off the performance stats on a struct disk_stats.
+ * @q: target block queue
  * @cpu: cpu number for stats access
  * @part: target partition
  *
@@ -1502,13 +1498,31 @@ static void part_round_stats_single(int cpu, struct hd_struct *part,
  * /proc/diskstats.  This accounts immediately for all queue usage up to
  * the current jiffies and restarts the counters again.
  */
-void part_round_stats(int cpu, struct hd_struct *part)
+void part_round_stats(struct request_queue *q, int cpu, struct hd_struct *part)
 {
+	struct hd_struct *part2 = NULL;
 	unsigned long now = jiffies;
+	unsigned int inflight[2];
+	int stats = 0;
+
+	if (part->stamp != now)
+		stats |= 1;
+
+	if (part->partno) {
+		part2 = &part_to_disk(part)->part0;
+		if (part2->stamp != now)
+			stats |= 2;
+	}
 
-	if (part->partno)
-		part_round_stats_single(cpu, &part_to_disk(part)->part0, now);
-	part_round_stats_single(cpu, part, now);
+	if (!stats)
+		return;
+
+	part_in_flight(q, part, inflight);
+
+	if (stats & 2)
+		part_round_stats_single(q, cpu, part2, now, inflight[1]);
+	if (stats & 1)
+		part_round_stats_single(q, cpu, part, now, inflight[0]);
 }
 EXPORT_SYMBOL_GPL(part_round_stats);
 
@@ -1896,40 +1910,15 @@ out_unlock:
 	return BLK_QC_T_NONE;
 }
 
-/*
- * If bio->bi_dev is a partition, remap the location
- */
-static inline void blk_partition_remap(struct bio *bio)
-{
-	struct block_device *bdev = bio->bi_bdev;
-
-	/*
-	 * Zone reset does not include bi_size so bio_sectors() is always 0.
-	 * Include a test for the reset op code and perform the remap if needed.
-	 */
-	if (bdev != bdev->bd_contains &&
-	    (bio_sectors(bio) || bio_op(bio) == REQ_OP_ZONE_RESET)) {
-		struct hd_struct *p = bdev->bd_part;
-
-		bio->bi_iter.bi_sector += p->start_sect;
-		bio->bi_bdev = bdev->bd_contains;
-
-		trace_block_bio_remap(bdev_get_queue(bio->bi_bdev), bio,
-				      bdev->bd_dev,
-				      bio->bi_iter.bi_sector - p->start_sect);
-	}
-}
-
 static void handle_bad_sector(struct bio *bio)
 {
 	char b[BDEVNAME_SIZE];
 
 	printk(KERN_INFO "attempt to access beyond end of device\n");
 	printk(KERN_INFO "%s: rw=%d, want=%Lu, limit=%Lu\n",
-			bdevname(bio->bi_bdev, b),
-			bio->bi_opf,
+			bio_devname(bio, b), bio->bi_opf,
 			(unsigned long long)bio_end_sector(bio),
-			(long long)(i_size_read(bio->bi_bdev->bd_inode) >> 9));
+			(long long)get_capacity(bio->bi_disk));
 }
 
 #ifdef CONFIG_FAIL_MAKE_REQUEST
@@ -1968,6 +1957,38 @@ static inline bool should_fail_request(struct hd_struct *part,
 #endif /* CONFIG_FAIL_MAKE_REQUEST */
 
 /*
+ * Remap block n of partition p to block n+start(p) of the disk.
+ */
+static inline int blk_partition_remap(struct bio *bio)
+{
+	struct hd_struct *p;
+	int ret = 0;
+
+	/*
+	 * Zone reset does not include bi_size so bio_sectors() is always 0.
+	 * Include a test for the reset op code and perform the remap if needed.
+	 */
+	if (!bio->bi_partno ||
+	    (!bio_sectors(bio) && bio_op(bio) != REQ_OP_ZONE_RESET))
+		return 0;
+
+	rcu_read_lock();
+	p = __disk_get_part(bio->bi_disk, bio->bi_partno);
+	if (likely(p && !should_fail_request(p, bio->bi_iter.bi_size))) {
+		bio->bi_iter.bi_sector += p->start_sect;
+		bio->bi_partno = 0;
+		trace_block_bio_remap(bio->bi_disk->queue, bio, part_devt(p),
+				bio->bi_iter.bi_sector - p->start_sect);
+	} else {
+		printk("%s: fail for partition %d\n", __func__, bio->bi_partno);
+		ret = -EIO;
+	}
+	rcu_read_unlock();
+
+	return ret;
+}
+
+/*
  * Check whether this bio extends beyond the end of the device.
  */
 static inline int bio_check_eod(struct bio *bio, unsigned int nr_sectors)
@@ -1978,7 +1999,7 @@ static inline int bio_check_eod(struct bio *bio, unsigned int nr_sectors)
 		return 0;
 
 	/* Test device or partition size, when known. */
-	maxsector = i_size_read(bio->bi_bdev->bd_inode) >> 9;
+	maxsector = get_capacity(bio->bi_disk);
 	if (maxsector) {
 		sector_t sector = bio->bi_iter.bi_sector;
 
@@ -2003,20 +2024,18 @@ generic_make_request_checks(struct bio *bio)
 	int nr_sectors = bio_sectors(bio);
 	blk_status_t status = BLK_STS_IOERR;
 	char b[BDEVNAME_SIZE];
-	struct hd_struct *part;
 
 	might_sleep();
 
 	if (bio_check_eod(bio, nr_sectors))
 		goto end_io;
 
-	q = bdev_get_queue(bio->bi_bdev);
+	q = bio->bi_disk->queue;
 	if (unlikely(!q)) {
 		printk(KERN_ERR
 		       "generic_make_request: Trying to access "
 			"nonexistent block-device %s (%Lu)\n",
-			bdevname(bio->bi_bdev, b),
-			(long long) bio->bi_iter.bi_sector);
+			bio_devname(bio, b), (long long)bio->bi_iter.bi_sector);
 		goto end_io;
 	}
 
@@ -2028,17 +2047,11 @@ generic_make_request_checks(struct bio *bio)
 	if ((bio->bi_opf & REQ_NOWAIT) && !queue_is_rq_based(q))
 		goto not_supported;
 
-	part = bio->bi_bdev->bd_part;
-	if (should_fail_request(part, bio->bi_iter.bi_size) ||
-	    should_fail_request(&part_to_disk(part)->part0,
-				bio->bi_iter.bi_size))
+	if (should_fail_request(&bio->bi_disk->part0, bio->bi_iter.bi_size))
 		goto end_io;
 
-	/*
-	 * If this device has partitions, remap block n
-	 * of partition p to block n+start(p) of the disk.
-	 */
-	blk_partition_remap(bio);
+	if (blk_partition_remap(bio))
+		goto end_io;
 
 	if (bio_check_eod(bio, nr_sectors))
 		goto end_io;
@@ -2067,16 +2080,16 @@ generic_make_request_checks(struct bio *bio)
 			goto not_supported;
 		break;
 	case REQ_OP_WRITE_SAME:
-		if (!bdev_write_same(bio->bi_bdev))
+		if (!q->limits.max_write_same_sectors)
 			goto not_supported;
 		break;
 	case REQ_OP_ZONE_REPORT:
 	case REQ_OP_ZONE_RESET:
-		if (!bdev_is_zoned(bio->bi_bdev))
+		if (!blk_queue_is_zoned(q))
 			goto not_supported;
 		break;
 	case REQ_OP_WRITE_ZEROES:
-		if (!bdev_write_zeroes_sectors(bio->bi_bdev))
+		if (!q->limits.max_write_zeroes_sectors)
 			goto not_supported;
 		break;
 	default:
@@ -2183,7 +2196,7 @@ blk_qc_t generic_make_request(struct bio *bio)
 	bio_list_init(&bio_list_on_stack[0]);
 	current->bio_list = bio_list_on_stack;
 	do {
-		struct request_queue *q = bdev_get_queue(bio->bi_bdev);
+		struct request_queue *q = bio->bi_disk->queue;
 
 		if (likely(blk_queue_enter(q, bio->bi_opf & REQ_NOWAIT) == 0)) {
 			struct bio_list lower, same;
@@ -2201,7 +2214,7 @@ blk_qc_t generic_make_request(struct bio *bio)
 			bio_list_init(&lower);
 			bio_list_init(&same);
 			while ((bio = bio_list_pop(&bio_list_on_stack[0])) != NULL)
-				if (q == bdev_get_queue(bio->bi_bdev))
+				if (q == bio->bi_disk->queue)
 					bio_list_add(&same, bio);
 				else
 					bio_list_add(&lower, bio);
@@ -2244,7 +2257,7 @@ blk_qc_t submit_bio(struct bio *bio)
 		unsigned int count;
 
 		if (unlikely(bio_op(bio) == REQ_OP_WRITE_SAME))
-			count = bdev_logical_block_size(bio->bi_bdev) >> 9;
+			count = queue_logical_block_size(bio->bi_disk->queue);
 		else
 			count = bio_sectors(bio);
 
@@ -2261,8 +2274,7 @@ blk_qc_t submit_bio(struct bio *bio)
 			current->comm, task_pid_nr(current),
 				op_is_write(bio_op(bio)) ? "WRITE" : "READ",
 				(unsigned long long)bio->bi_iter.bi_sector,
-				bdevname(bio->bi_bdev, b),
-				count);
+				bio_devname(bio, b), count);
 		}
 	}
 
@@ -2431,8 +2443,8 @@ void blk_account_io_done(struct request *req)
 
 		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);
+		part_round_stats(req->q, cpu, part);
+		part_dec_in_flight(req->q, part, rw);
 
 		hd_struct_put(part);
 		part_stat_unlock();
@@ -2489,8 +2501,8 @@ void blk_account_io_start(struct request *rq, bool new_io)
 			part = &rq->rq_disk->part0;
 			hd_struct_get(part);
 		}
-		part_round_stats(cpu, part);
-		part_inc_in_flight(part, rw);
+		part_round_stats(rq->q, cpu, part);
+		part_inc_in_flight(rq->q, part, rw);
 		rq->part = part;
 	}
 
@@ -2603,7 +2615,7 @@ struct request *blk_peek_request(struct request_queue *q)
 }
 EXPORT_SYMBOL(blk_peek_request);
 
-void blk_dequeue_request(struct request *rq)
+static void blk_dequeue_request(struct request *rq)
 {
 	struct request_queue *q = rq->q;
 
@@ -2630,9 +2642,6 @@ void blk_dequeue_request(struct request *rq)
  * Description:
  *     Dequeue @req and start timeout timer on it.  This hands off the
  *     request to the driver.
- *
- *     Block internal functions which don't want to start timer should
- *     call blk_dequeue_request().
  */
 void blk_start_request(struct request *req)
 {
@@ -3035,8 +3044,8 @@ void blk_rq_bio_prep(struct request_queue *q, struct request *rq,
 	rq->__data_len = bio->bi_iter.bi_size;
 	rq->bio = rq->biotail = bio;
 
-	if (bio->bi_bdev)
-		rq->rq_disk = bio->bi_bdev->bd_disk;
+	if (bio->bi_disk)
+		rq->rq_disk = bio->bi_disk;
 }
 
 #if ARCH_IMPLEMENTS_FLUSH_DCACHE_PAGE
diff --git a/block/blk-flush.c b/block/blk-flush.c
index ed5fe322abba..4938bec8cfef 100644
--- a/block/blk-flush.c
+++ b/block/blk-flush.c
@@ -1,12 +1,12 @@
 /*
- * Functions to sequence FLUSH and FUA writes.
+ * Functions to sequence PREFLUSH and FUA writes.
  *
  * Copyright (C) 2011		Max Planck Institute for Gravitational Physics
  * Copyright (C) 2011		Tejun Heo <tj@kernel.org>
  *
  * This file is released under the GPLv2.
  *
- * REQ_{FLUSH|FUA} requests are decomposed to sequences consisted of three
+ * REQ_{PREFLUSH|FUA} requests are decomposed to sequences consisted of three
  * optional steps - PREFLUSH, DATA and POSTFLUSH - according to the request
  * properties and hardware capability.
  *
@@ -16,9 +16,9 @@
  * REQ_FUA means that the data must be on non-volatile media on request
  * completion.
  *
- * If the device doesn't have writeback cache, FLUSH and FUA don't make any
- * difference.  The requests are either completed immediately if there's no
- * data or executed as normal requests otherwise.
+ * If the device doesn't have writeback cache, PREFLUSH and FUA don't make any
+ * difference.  The requests are either completed immediately if there's no data
+ * or executed as normal requests otherwise.
  *
  * If the device has writeback cache and supports FUA, REQ_PREFLUSH is
  * translated to PREFLUSH but REQ_FUA is passed down directly with DATA.
@@ -31,7 +31,7 @@
  * fq->flush_queue[fq->flush_pending_idx].  Once certain criteria are met, a
  * REQ_OP_FLUSH is issued and the pending_idx is toggled.  When the flush
  * completes, all the requests which were pending are proceeded to the next
- * step.  This allows arbitrary merging of different types of FLUSH/FUA
+ * step.  This allows arbitrary merging of different types of PREFLUSH/FUA
  * requests.
  *
  * Currently, the following conditions are used to determine when to issue
@@ -47,19 +47,19 @@
  * C3. The second condition is ignored if there is a request which has
  *     waited longer than FLUSH_PENDING_TIMEOUT.  This is to avoid
  *     starvation in the unlikely case where there are continuous stream of
- *     FUA (without FLUSH) requests.
+ *     FUA (without PREFLUSH) requests.
  *
  * For devices which support FUA, it isn't clear whether C2 (and thus C3)
  * is beneficial.
  *
- * Note that a sequenced FLUSH/FUA request with DATA is completed twice.
+ * Note that a sequenced PREFLUSH/FUA request with DATA is completed twice.
  * Once while executing DATA and again after the whole sequence is
  * complete.  The first completion updates the contained bio but doesn't
  * finish it so that the bio submitter is notified only after the whole
  * sequence is complete.  This is implemented by testing RQF_FLUSH_SEQ in
  * req_bio_endio().
  *
- * The above peculiarity requires that each FLUSH/FUA request has only one
+ * The above peculiarity requires that each PREFLUSH/FUA request has only one
  * bio attached to it, which is guaranteed as they aren't allowed to be
  * merged in the usual way.
  */
@@ -76,7 +76,7 @@
 #include "blk-mq-tag.h"
 #include "blk-mq-sched.h"
 
-/* FLUSH/FUA sequences */
+/* PREFLUSH/FUA sequences */
 enum {
 	REQ_FSEQ_PREFLUSH	= (1 << 0), /* pre-flushing in progress */
 	REQ_FSEQ_DATA		= (1 << 1), /* data write in progress */
@@ -148,7 +148,7 @@ static bool blk_flush_queue_rq(struct request *rq, bool add_front)
 
 /**
  * blk_flush_complete_seq - complete flush sequence
- * @rq: FLUSH/FUA request being sequenced
+ * @rq: PREFLUSH/FUA request being sequenced
  * @fq: flush queue
  * @seq: sequences to complete (mask of %REQ_FSEQ_*, can be zero)
  * @error: whether an error occurred
@@ -406,7 +406,7 @@ static void mq_flush_data_end_io(struct request *rq, blk_status_t error)
 }
 
 /**
- * blk_insert_flush - insert a new FLUSH/FUA request
+ * blk_insert_flush - insert a new PREFLUSH/FUA request
  * @rq: request to insert
  *
  * To be called from __elv_add_request() for %ELEVATOR_INSERT_FLUSH insertions.
@@ -525,7 +525,7 @@ int blkdev_issue_flush(struct block_device *bdev, gfp_t gfp_mask,
 		return -ENXIO;
 
 	bio = bio_alloc(gfp_mask, 0);
-	bio->bi_bdev = bdev;
+	bio_set_dev(bio, bdev);
 	bio->bi_opf = REQ_OP_WRITE | REQ_PREFLUSH;
 
 	ret = submit_bio_wait(bio);
diff --git a/block/blk-lib.c b/block/blk-lib.c
index 3fe0aec90597..e01adb5145b3 100644
--- a/block/blk-lib.c
+++ b/block/blk-lib.c
@@ -77,7 +77,7 @@ int __blkdev_issue_discard(struct block_device *bdev, sector_t sector,
 
 		bio = next_bio(bio, 0, gfp_mask);
 		bio->bi_iter.bi_sector = sector;
-		bio->bi_bdev = bdev;
+		bio_set_dev(bio, bdev);
 		bio_set_op_attrs(bio, op, 0);
 
 		bio->bi_iter.bi_size = req_sects << 9;
@@ -168,7 +168,7 @@ static int __blkdev_issue_write_same(struct block_device *bdev, sector_t sector,
 	while (nr_sects) {
 		bio = next_bio(bio, 1, gfp_mask);
 		bio->bi_iter.bi_sector = sector;
-		bio->bi_bdev = bdev;
+		bio_set_dev(bio, bdev);
 		bio->bi_vcnt = 1;
 		bio->bi_io_vec->bv_page = page;
 		bio->bi_io_vec->bv_offset = 0;
@@ -241,7 +241,7 @@ static int __blkdev_issue_write_zeroes(struct block_device *bdev,
 	while (nr_sects) {
 		bio = next_bio(bio, 0, gfp_mask);
 		bio->bi_iter.bi_sector = sector;
-		bio->bi_bdev = bdev;
+		bio_set_dev(bio, bdev);
 		bio->bi_opf = REQ_OP_WRITE_ZEROES;
 		if (flags & BLKDEV_ZERO_NOUNMAP)
 			bio->bi_opf |= REQ_NOUNMAP;
@@ -323,7 +323,7 @@ int __blkdev_issue_zeroout(struct block_device *bdev, sector_t sector,
 		bio = next_bio(bio, __blkdev_sectors_to_bio_pages(nr_sects),
 			       gfp_mask);
 		bio->bi_iter.bi_sector = sector;
-		bio->bi_bdev   = bdev;
+		bio_set_dev(bio, bdev);
 		bio_set_op_attrs(bio, REQ_OP_WRITE, 0);
 
 		while (nr_sects != 0) {
diff --git a/block/blk-merge.c b/block/blk-merge.c
index 99038830fb42..aa524cad5bea 100644
--- a/block/blk-merge.c
+++ b/block/blk-merge.c
@@ -633,8 +633,8 @@ static void blk_account_io_merge(struct request *req)
 		cpu = part_stat_lock();
 		part = req->part;
 
-		part_round_stats(cpu, part);
-		part_dec_in_flight(part, rq_data_dir(req));
+		part_round_stats(req->q, cpu, part);
+		part_dec_in_flight(req->q, part, rq_data_dir(req));
 
 		hd_struct_put(part);
 		part_stat_unlock();
@@ -786,7 +786,7 @@ bool blk_rq_merge_ok(struct request *rq, struct bio *bio)
 		return false;
 
 	/* must be same device and not a special request */
-	if (rq->rq_disk != bio->bi_bdev->bd_disk || req_no_special_merge(rq))
+	if (rq->rq_disk != bio->bi_disk || req_no_special_merge(rq))
 		return false;
 
 	/* only merge integrity protected bio into ditto rq */
diff --git a/block/blk-mq-debugfs.c b/block/blk-mq-debugfs.c
index 4f927a58dff8..980e73095643 100644
--- a/block/blk-mq-debugfs.c
+++ b/block/blk-mq-debugfs.c
@@ -48,8 +48,6 @@ static int blk_flags_show(struct seq_file *m, const unsigned long flags,
 static const char *const blk_queue_flag_name[] = {
 	QUEUE_FLAG_NAME(QUEUED),
 	QUEUE_FLAG_NAME(STOPPED),
-	QUEUE_FLAG_NAME(SYNCFULL),
-	QUEUE_FLAG_NAME(ASYNCFULL),
 	QUEUE_FLAG_NAME(DYING),
 	QUEUE_FLAG_NAME(BYPASS),
 	QUEUE_FLAG_NAME(BIDI),
@@ -744,7 +742,7 @@ static int blk_mq_debugfs_release(struct inode *inode, struct file *file)
 		return seq_release(inode, file);
 }
 
-const struct file_operations blk_mq_debugfs_fops = {
+static const struct file_operations blk_mq_debugfs_fops = {
 	.open		= blk_mq_debugfs_open,
 	.read		= seq_read,
 	.write		= blk_mq_debugfs_write,
diff --git a/block/blk-mq-tag.c b/block/blk-mq-tag.c
index d0be72ccb091..6714507aa6c7 100644
--- a/block/blk-mq-tag.c
+++ b/block/blk-mq-tag.c
@@ -214,7 +214,11 @@ static bool bt_iter(struct sbitmap *bitmap, unsigned int bitnr, void *data)
 		bitnr += tags->nr_reserved_tags;
 	rq = tags->rqs[bitnr];
 
-	if (rq->q == hctx->queue)
+	/*
+	 * We can hit rq == NULL here, because the tagging functions
+	 * test and set the bit before assining ->rqs[].
+	 */
+	if (rq && rq->q == hctx->queue)
 		iter_data->fn(hctx, rq, iter_data->data, reserved);
 	return true;
 }
@@ -248,9 +252,15 @@ static bool bt_tags_iter(struct sbitmap *bitmap, unsigned int bitnr, void *data)
 
 	if (!reserved)
 		bitnr += tags->nr_reserved_tags;
+
+	/*
+	 * We can hit rq == NULL here, because the tagging functions
+	 * test and set the bit before assining ->rqs[].
+	 */
 	rq = tags->rqs[bitnr];
+	if (rq)
+		iter_data->fn(rq, iter_data->data, reserved);
 
-	iter_data->fn(rq, iter_data->data, reserved);
 	return true;
 }
 
@@ -288,11 +298,12 @@ void blk_mq_tagset_busy_iter(struct blk_mq_tag_set *tagset,
 }
 EXPORT_SYMBOL(blk_mq_tagset_busy_iter);
 
-int blk_mq_reinit_tagset(struct blk_mq_tag_set *set)
+int blk_mq_reinit_tagset(struct blk_mq_tag_set *set,
+			 int (reinit_request)(void *, struct request *))
 {
 	int i, j, ret = 0;
 
-	if (!set->ops->reinit_request)
+	if (WARN_ON_ONCE(!reinit_request))
 		goto out;
 
 	for (i = 0; i < set->nr_hw_queues; i++) {
@@ -305,8 +316,8 @@ int blk_mq_reinit_tagset(struct blk_mq_tag_set *set)
 			if (!tags->static_rqs[j])
 				continue;
 
-			ret = set->ops->reinit_request(set->driver_data,
-						tags->static_rqs[j]);
+			ret = reinit_request(set->driver_data,
+					     tags->static_rqs[j]);
 			if (ret)
 				goto out;
 		}
diff --git a/block/blk-mq.c b/block/blk-mq.c
index 4603b115e234..3f18cff80050 100644
--- a/block/blk-mq.c
+++ b/block/blk-mq.c
@@ -83,6 +83,41 @@ static void blk_mq_hctx_clear_pending(struct blk_mq_hw_ctx *hctx,
 	sbitmap_clear_bit(&hctx->ctx_map, ctx->index_hw);
 }
 
+struct mq_inflight {
+	struct hd_struct *part;
+	unsigned int *inflight;
+};
+
+static void blk_mq_check_inflight(struct blk_mq_hw_ctx *hctx,
+				  struct request *rq, void *priv,
+				  bool reserved)
+{
+	struct mq_inflight *mi = priv;
+
+	if (test_bit(REQ_ATOM_STARTED, &rq->atomic_flags) &&
+	    !test_bit(REQ_ATOM_COMPLETE, &rq->atomic_flags)) {
+		/*
+		 * index[0] counts the specific partition that was asked
+		 * for. index[1] counts the ones that are active on the
+		 * whole device, so increment that if mi->part is indeed
+		 * a partition, and not a whole device.
+		 */
+		if (rq->part == mi->part)
+			mi->inflight[0]++;
+		if (mi->part->partno)
+			mi->inflight[1]++;
+	}
+}
+
+void blk_mq_in_flight(struct request_queue *q, struct hd_struct *part,
+		      unsigned int inflight[2])
+{
+	struct mq_inflight mi = { .part = part, .inflight = inflight, };
+
+	inflight[0] = inflight[1] = 0;
+	blk_mq_queue_tag_busy_iter(q, blk_mq_check_inflight, &mi);
+}
+
 void blk_freeze_queue_start(struct request_queue *q)
 {
 	int freeze_depth;
@@ -624,11 +659,10 @@ static void blk_mq_requeue_work(struct work_struct *work)
 		container_of(work, struct request_queue, requeue_work.work);
 	LIST_HEAD(rq_list);
 	struct request *rq, *next;
-	unsigned long flags;
 
-	spin_lock_irqsave(&q->requeue_lock, flags);
+	spin_lock_irq(&q->requeue_lock);
 	list_splice_init(&q->requeue_list, &rq_list);
-	spin_unlock_irqrestore(&q->requeue_lock, flags);
+	spin_unlock_irq(&q->requeue_lock);
 
 	list_for_each_entry_safe(rq, next, &rq_list, queuelist) {
 		if (!(rq->rq_flags & RQF_SOFTBARRIER))
@@ -1102,9 +1136,19 @@ static void __blk_mq_run_hw_queue(struct blk_mq_hw_ctx *hctx)
 {
 	int srcu_idx;
 
+	/*
+	 * We should be running this queue from one of the CPUs that
+	 * are mapped to it.
+	 */
 	WARN_ON(!cpumask_test_cpu(raw_smp_processor_id(), hctx->cpumask) &&
 		cpu_online(hctx->next_cpu));
 
+	/*
+	 * We can't run the queue inline with ints disabled. Ensure that
+	 * we catch bad users of this early.
+	 */
+	WARN_ON_ONCE(in_interrupt());
+
 	if (!(hctx->flags & BLK_MQ_F_BLOCKING)) {
 		rcu_read_lock();
 		blk_mq_sched_dispatch_requests(hctx);
@@ -1218,7 +1262,7 @@ EXPORT_SYMBOL(blk_mq_queue_stopped);
 /*
  * This function is often used for pausing .queue_rq() by driver when
  * there isn't enough resource or some conditions aren't satisfied, and
- * BLK_MQ_RQ_QUEUE_BUSY is usually returned.
+ * BLK_STS_RESOURCE is usually returned.
  *
  * We do not guarantee that dispatch can be drained or blocked
  * after blk_mq_stop_hw_queue() returns. Please use
@@ -1235,7 +1279,7 @@ EXPORT_SYMBOL(blk_mq_stop_hw_queue);
 /*
  * This function is often used for pausing .queue_rq() by driver when
  * there isn't enough resource or some conditions aren't satisfied, and
- * BLK_MQ_RQ_QUEUE_BUSY is usually returned.
+ * BLK_STS_RESOURCE is usually returned.
  *
  * We do not guarantee that dispatch can be drained or blocked
  * after blk_mq_stop_hw_queues() returns. Please use
diff --git a/block/blk-mq.h b/block/blk-mq.h
index 60b01c0309bc..98252b79b80b 100644
--- a/block/blk-mq.h
+++ b/block/blk-mq.h
@@ -133,4 +133,7 @@ static inline bool blk_mq_hw_queue_mapped(struct blk_mq_hw_ctx *hctx)
 	return hctx->nr_ctx && hctx->tags;
 }
 
+void blk_mq_in_flight(struct request_queue *q, struct hd_struct *part,
+			unsigned int inflight[2]);
+
 #endif
diff --git a/block/blk-settings.c b/block/blk-settings.c
index be1f115b538b..8559e9563c52 100644
--- a/block/blk-settings.c
+++ b/block/blk-settings.c
@@ -68,6 +68,7 @@ EXPORT_SYMBOL_GPL(blk_queue_rq_timeout);
 
 void blk_queue_rq_timed_out(struct request_queue *q, rq_timed_out_fn *fn)
 {
+	WARN_ON_ONCE(q->mq_ops);
 	q->rq_timed_out_fn = fn;
 }
 EXPORT_SYMBOL_GPL(blk_queue_rq_timed_out);
diff --git a/block/blk-sysfs.c b/block/blk-sysfs.c
index 27aceab1cc31..b8362c0df51d 100644
--- a/block/blk-sysfs.c
+++ b/block/blk-sysfs.c
@@ -931,7 +931,9 @@ void blk_unregister_queue(struct gendisk *disk)
 	if (WARN_ON(!q))
 		return;
 
+	mutex_lock(&q->sysfs_lock);
 	queue_flag_clear_unlocked(QUEUE_FLAG_REGISTERED, q);
+	mutex_unlock(&q->sysfs_lock);
 
 	wbt_exit(q);
 
diff --git a/block/blk-tag.c b/block/blk-tag.c
index 2290f65b9d73..e1a9c15eb1b8 100644
--- a/block/blk-tag.c
+++ b/block/blk-tag.c
@@ -290,7 +290,6 @@ void blk_queue_end_tag(struct request_queue *q, struct request *rq)
 	 */
 	clear_bit_unlock(tag, bqt->tag_map);
 }
-EXPORT_SYMBOL(blk_queue_end_tag);
 
 /**
  * blk_queue_start_tag - find a free tag and assign it
diff --git a/block/blk-throttle.c b/block/blk-throttle.c
index 80f5481fe9f6..0fea76aa0f3f 100644
--- a/block/blk-throttle.c
+++ b/block/blk-throttle.c
@@ -373,10 +373,8 @@ static unsigned int tg_iops_limit(struct throtl_grp *tg, int rw)
 	if (likely(!blk_trace_note_message_enabled(__td->queue)))	\
 		break;							\
 	if ((__tg)) {							\
-		char __pbuf[128];					\
-									\
-		blkg_path(tg_to_blkg(__tg), __pbuf, sizeof(__pbuf));	\
-		blk_add_trace_msg(__td->queue, "throtl %s " fmt, __pbuf, ##args); \
+		blk_add_cgroup_trace_msg(__td->queue,			\
+			tg_to_blkg(__tg)->blkcg, "throtl " fmt, ##args);\
 	} else {							\
 		blk_add_trace_msg(__td->queue, "throtl " fmt, ##args);	\
 	}								\
@@ -2114,14 +2112,9 @@ static inline void throtl_update_latency_buckets(struct throtl_data *td)
 static void blk_throtl_assoc_bio(struct throtl_grp *tg, struct bio *bio)
 {
 #ifdef CONFIG_BLK_DEV_THROTTLING_LOW
-	int ret;
-
-	ret = bio_associate_current(bio);
-	if (ret == 0 || ret == -EBUSY)
+	if (bio->bi_css)
 		bio->bi_cg_private = tg;
 	blk_stat_set_issue(&bio->bi_issue_stat, bio_sectors(bio));
-#else
-	bio_associate_current(bio);
 #endif
 }
 
diff --git a/block/blk-zoned.c b/block/blk-zoned.c
index 3bd15d8095b1..ff57fb51b338 100644
--- a/block/blk-zoned.c
+++ b/block/blk-zoned.c
@@ -116,7 +116,7 @@ int blkdev_report_zones(struct block_device *bdev,
 	if (!bio)
 		return -ENOMEM;
 
-	bio->bi_bdev = bdev;
+	bio_set_dev(bio, bdev);
 	bio->bi_iter.bi_sector = blk_zone_start(q, sector);
 	bio_set_op_attrs(bio, REQ_OP_ZONE_REPORT, 0);
 
@@ -234,7 +234,7 @@ int blkdev_reset_zones(struct block_device *bdev,
 
 		bio = bio_alloc(gfp_mask, 0);
 		bio->bi_iter.bi_sector = sector;
-		bio->bi_bdev = bdev;
+		bio_set_dev(bio, bdev);
 		bio_set_op_attrs(bio, REQ_OP_ZONE_RESET, 0);
 
 		ret = submit_bio_wait(bio);
diff --git a/block/blk.h b/block/blk.h
index 3a3d715bd725..fcb9775b997d 100644
--- a/block/blk.h
+++ b/block/blk.h
@@ -64,7 +64,6 @@ void blk_rq_bio_prep(struct request_queue *q, struct request *rq,
 			struct bio *bio);
 void blk_queue_bypass_start(struct request_queue *q);
 void blk_queue_bypass_end(struct request_queue *q);
-void blk_dequeue_request(struct request *rq);
 void __blk_queue_free_tags(struct request_queue *q);
 void blk_freeze_queue(struct request_queue *q);
 
@@ -204,6 +203,8 @@ static inline void elv_deactivate_rq(struct request_queue *q, struct request *rq
 		e->type->ops.sq.elevator_deactivate_req_fn(q, rq);
 }
 
+struct hd_struct *__disk_get_part(struct gendisk *disk, int partno);
+
 #ifdef CONFIG_FAIL_IO_TIMEOUT
 int blk_should_fake_timeout(struct request_queue *);
 ssize_t part_timeout_show(struct device *, struct device_attribute *, char *);
diff --git a/block/bsg.c b/block/bsg.c
index 37663b664666..ee1335c68de7 100644
--- a/block/bsg.c
+++ b/block/bsg.c
@@ -932,15 +932,8 @@ static long bsg_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
 
 		return ret;
 	}
-	/*
-	 * block device ioctls
-	 */
 	default:
-#if 0
-		return ioctl_by_bdev(bd->bdev, cmd, arg);
-#else
 		return -ENOTTY;
-#endif
 	}
 }
 
diff --git a/block/cfq-iosched.c b/block/cfq-iosched.c
index 3d5c28945719..9b86e9b352e9 100644
--- a/block/cfq-iosched.c
+++ b/block/cfq-iosched.c
@@ -656,20 +656,17 @@ static inline void cfqg_put(struct cfq_group *cfqg)
 }
 
 #define cfq_log_cfqq(cfqd, cfqq, fmt, args...)	do {			\
-	char __pbuf[128];						\
-									\
-	blkg_path(cfqg_to_blkg((cfqq)->cfqg), __pbuf, sizeof(__pbuf));	\
-	blk_add_trace_msg((cfqd)->queue, "cfq%d%c%c %s " fmt, (cfqq)->pid, \
+	blk_add_cgroup_trace_msg((cfqd)->queue,				\
+			cfqg_to_blkg((cfqq)->cfqg)->blkcg,		\
+			"cfq%d%c%c " fmt, (cfqq)->pid,			\
 			cfq_cfqq_sync((cfqq)) ? 'S' : 'A',		\
 			cfqq_type((cfqq)) == SYNC_NOIDLE_WORKLOAD ? 'N' : ' ',\
-			  __pbuf, ##args);				\
+			  ##args);					\
 } while (0)
 
 #define cfq_log_cfqg(cfqd, cfqg, fmt, args...)	do {			\
-	char __pbuf[128];						\
-									\
-	blkg_path(cfqg_to_blkg(cfqg), __pbuf, sizeof(__pbuf));		\
-	blk_add_trace_msg((cfqd)->queue, "%s " fmt, __pbuf, ##args);	\
+	blk_add_cgroup_trace_msg((cfqd)->queue,				\
+			cfqg_to_blkg(cfqg)->blkcg, fmt, ##args);	\
 } while (0)
 
 static inline void cfqg_stats_update_io_add(struct cfq_group *cfqg,
@@ -2937,7 +2934,8 @@ static void cfq_arm_slice_timer(struct cfq_data *cfqd)
 	 * for devices that support queuing, otherwise we still have a problem
 	 * with sync vs async workloads.
 	 */
-	if (blk_queue_nonrot(cfqd->queue) && cfqd->hw_tag)
+	if (blk_queue_nonrot(cfqd->queue) && cfqd->hw_tag &&
+		!cfqd->cfq_group_idle)
 		return;
 
 	WARN_ON(!RB_EMPTY_ROOT(&cfqq->sort_list));
@@ -4714,13 +4712,12 @@ cfq_var_show(unsigned int var, char *page)
 	return sprintf(page, "%u\n", var);
 }
 
-static ssize_t
-cfq_var_store(unsigned int *var, const char *page, size_t count)
+static void
+cfq_var_store(unsigned int *var, const char *page)
 {
 	char *p = (char *) page;
 
 	*var = simple_strtoul(p, &p, 10);
-	return count;
 }
 
 #define SHOW_FUNCTION(__FUNC, __VAR, __CONV)				\
@@ -4766,7 +4763,7 @@ static ssize_t __FUNC(struct elevator_queue *e, const char *page, size_t count)
 {									\
 	struct cfq_data *cfqd = e->elevator_data;			\
 	unsigned int __data;						\
-	int ret = cfq_var_store(&__data, (page), count);		\
+	cfq_var_store(&__data, (page));					\
 	if (__data < (MIN))						\
 		__data = (MIN);						\
 	else if (__data > (MAX))					\
@@ -4775,7 +4772,7 @@ static ssize_t __FUNC(struct elevator_queue *e, const char *page, size_t count)
 		*(__PTR) = (u64)__data * NSEC_PER_MSEC;			\
 	else								\
 		*(__PTR) = __data;					\
-	return ret;							\
+	return count;							\
 }
 STORE_FUNCTION(cfq_quantum_store, &cfqd->cfq_quantum, 1, UINT_MAX, 0);
 STORE_FUNCTION(cfq_fifo_expire_sync_store, &cfqd->cfq_fifo_expire[1], 1,
@@ -4800,13 +4797,13 @@ static ssize_t __FUNC(struct elevator_queue *e, const char *page, size_t count)
 {									\
 	struct cfq_data *cfqd = e->elevator_data;			\
 	unsigned int __data;						\
-	int ret = cfq_var_store(&__data, (page), count);		\
+	cfq_var_store(&__data, (page));					\
 	if (__data < (MIN))						\
 		__data = (MIN);						\
 	else if (__data > (MAX))					\
 		__data = (MAX);						\
 	*(__PTR) = (u64)__data * NSEC_PER_USEC;				\
-	return ret;							\
+	return count;							\
 }
 USEC_STORE_FUNCTION(cfq_slice_idle_us_store, &cfqd->cfq_slice_idle, 0, UINT_MAX);
 USEC_STORE_FUNCTION(cfq_group_idle_us_store, &cfqd->cfq_group_idle, 0, UINT_MAX);
diff --git a/block/deadline-iosched.c b/block/deadline-iosched.c
index c68f6bbc0dcd..b83f77460d28 100644
--- a/block/deadline-iosched.c
+++ b/block/deadline-iosched.c
@@ -373,13 +373,12 @@ deadline_var_show(int var, char *page)
 	return sprintf(page, "%d\n", var);
 }
 
-static ssize_t
-deadline_var_store(int *var, const char *page, size_t count)
+static void
+deadline_var_store(int *var, const char *page)
 {
 	char *p = (char *) page;
 
 	*var = simple_strtol(p, &p, 10);
-	return count;
 }
 
 #define SHOW_FUNCTION(__FUNC, __VAR, __CONV)				\
@@ -403,7 +402,7 @@ static ssize_t __FUNC(struct elevator_queue *e, const char *page, size_t count)
 {									\
 	struct deadline_data *dd = e->elevator_data;			\
 	int __data;							\
-	int ret = deadline_var_store(&__data, (page), count);		\
+	deadline_var_store(&__data, (page));				\
 	if (__data < (MIN))						\
 		__data = (MIN);						\
 	else if (__data > (MAX))					\
@@ -412,7 +411,7 @@ static ssize_t __FUNC(struct elevator_queue *e, const char *page, size_t count)
 		*(__PTR) = msecs_to_jiffies(__data);			\
 	else								\
 		*(__PTR) = __data;					\
-	return ret;							\
+	return count;							\
 }
 STORE_FUNCTION(deadline_read_expire_store, &dd->fifo_expire[READ], 0, INT_MAX, 1);
 STORE_FUNCTION(deadline_write_expire_store, &dd->fifo_expire[WRITE], 0, INT_MAX, 1);
diff --git a/block/elevator.c b/block/elevator.c
index 4bb2f0c93fa6..153926a90901 100644
--- a/block/elevator.c
+++ b/block/elevator.c
@@ -1055,6 +1055,10 @@ static int __elevator_change(struct request_queue *q, const char *name)
 	char elevator_name[ELV_NAME_MAX];
 	struct elevator_type *e;
 
+	/* Make sure queue is not in the middle of being removed */
+	if (!test_bit(QUEUE_FLAG_REGISTERED, &q->queue_flags))
+		return -ENOENT;
+
 	/*
 	 * Special case for mq, turn off scheduling
 	 */
diff --git a/block/genhd.c b/block/genhd.c
index 51c1d407d93c..dd305c65ffb0 100644
--- a/block/genhd.c
+++ b/block/genhd.c
@@ -45,6 +45,52 @@ static void disk_add_events(struct gendisk *disk);
 static void disk_del_events(struct gendisk *disk);
 static void disk_release_events(struct gendisk *disk);
 
+void part_inc_in_flight(struct request_queue *q, struct hd_struct *part, int rw)
+{
+	if (q->mq_ops)
+		return;
+
+	atomic_inc(&part->in_flight[rw]);
+	if (part->partno)
+		atomic_inc(&part_to_disk(part)->part0.in_flight[rw]);
+}
+
+void part_dec_in_flight(struct request_queue *q, struct hd_struct *part, int rw)
+{
+	if (q->mq_ops)
+		return;
+
+	atomic_dec(&part->in_flight[rw]);
+	if (part->partno)
+		atomic_dec(&part_to_disk(part)->part0.in_flight[rw]);
+}
+
+void part_in_flight(struct request_queue *q, struct hd_struct *part,
+		    unsigned int inflight[2])
+{
+	if (q->mq_ops) {
+		blk_mq_in_flight(q, part, inflight);
+		return;
+	}
+
+	inflight[0] = atomic_read(&part->in_flight[0]) +
+			atomic_read(&part->in_flight[1]);
+	if (part->partno) {
+		part = &part_to_disk(part)->part0;
+		inflight[1] = atomic_read(&part->in_flight[0]) +
+				atomic_read(&part->in_flight[1]);
+	}
+}
+
+struct hd_struct *__disk_get_part(struct gendisk *disk, int partno)
+{
+	struct disk_part_tbl *ptbl = rcu_dereference(disk->part_tbl);
+
+	if (unlikely(partno < 0 || partno >= ptbl->len))
+		return NULL;
+	return rcu_dereference(ptbl->part[partno]);
+}
+
 /**
  * disk_get_part - get partition
  * @disk: disk to look partition from
@@ -61,21 +107,12 @@ static void disk_release_events(struct gendisk *disk);
  */
 struct hd_struct *disk_get_part(struct gendisk *disk, int partno)
 {
-	struct hd_struct *part = NULL;
-	struct disk_part_tbl *ptbl;
-
-	if (unlikely(partno < 0))
-		return NULL;
+	struct hd_struct *part;
 
 	rcu_read_lock();
-
-	ptbl = rcu_dereference(disk->part_tbl);
-	if (likely(partno < ptbl->len)) {
-		part = rcu_dereference(ptbl->part[partno]);
-		if (part)
-			get_device(part_to_dev(part));
-	}
-
+	part = __disk_get_part(disk, partno);
+	if (part)
+		get_device(part_to_dev(part));
 	rcu_read_unlock();
 
 	return part;
@@ -1098,12 +1135,13 @@ static const struct attribute_group *disk_attr_groups[] = {
  * original ptbl is freed using RCU callback.
  *
  * LOCKING:
- * Matching bd_mutx locked.
+ * Matching bd_mutex locked or the caller is the only user of @disk.
  */
 static void disk_replace_part_tbl(struct gendisk *disk,
 				  struct disk_part_tbl *new_ptbl)
 {
-	struct disk_part_tbl *old_ptbl = disk->part_tbl;
+	struct disk_part_tbl *old_ptbl =
+		rcu_dereference_protected(disk->part_tbl, 1);
 
 	rcu_assign_pointer(disk->part_tbl, new_ptbl);
 
@@ -1122,14 +1160,16 @@ static void disk_replace_part_tbl(struct gendisk *disk,
  * uses RCU to allow unlocked dereferencing for stats and other stuff.
  *
  * LOCKING:
- * Matching bd_mutex locked, might sleep.
+ * Matching bd_mutex locked or the caller is the only user of @disk.
+ * Might sleep.
  *
  * RETURNS:
  * 0 on success, -errno on failure.
  */
 int disk_expand_part_tbl(struct gendisk *disk, int partno)
 {
-	struct disk_part_tbl *old_ptbl = disk->part_tbl;
+	struct disk_part_tbl *old_ptbl =
+		rcu_dereference_protected(disk->part_tbl, 1);
 	struct disk_part_tbl *new_ptbl;
 	int len = old_ptbl ? old_ptbl->len : 0;
 	int i, target;
@@ -1212,6 +1252,7 @@ static int diskstats_show(struct seq_file *seqf, void *v)
 	struct disk_part_iter piter;
 	struct hd_struct *hd;
 	char buf[BDEVNAME_SIZE];
+	unsigned int inflight[2];
 	int cpu;
 
 	/*
@@ -1225,8 +1266,9 @@ static int diskstats_show(struct seq_file *seqf, void *v)
 	disk_part_iter_init(&piter, gp, DISK_PITER_INCL_EMPTY_PART0);
 	while ((hd = disk_part_iter_next(&piter))) {
 		cpu = part_stat_lock();
-		part_round_stats(cpu, hd);
+		part_round_stats(gp->queue, cpu, hd);
 		part_stat_unlock();
+		part_in_flight(gp->queue, hd, inflight);
 		seq_printf(seqf, "%4d %7d %s %lu %lu %lu "
 			   "%u %lu %lu %lu %u %u %u %u\n",
 			   MAJOR(part_devt(hd)), MINOR(part_devt(hd)),
@@ -1239,7 +1281,7 @@ static int diskstats_show(struct seq_file *seqf, void *v)
 			   part_stat_read(hd, merges[WRITE]),
 			   part_stat_read(hd, sectors[WRITE]),
 			   jiffies_to_msecs(part_stat_read(hd, ticks[WRITE])),
-			   part_in_flight(hd),
+			   inflight[0],
 			   jiffies_to_msecs(part_stat_read(hd, io_ticks)),
 			   jiffies_to_msecs(part_stat_read(hd, time_in_queue))
 			);
@@ -1321,6 +1363,14 @@ EXPORT_SYMBOL(alloc_disk);
 struct gendisk *alloc_disk_node(int minors, int node_id)
 {
 	struct gendisk *disk;
+	struct disk_part_tbl *ptbl;
+
+	if (minors > DISK_MAX_PARTS) {
+		printk(KERN_ERR
+			"block: can't allocated more than %d partitions\n",
+			DISK_MAX_PARTS);
+		minors = DISK_MAX_PARTS;
+	}
 
 	disk = kzalloc_node(sizeof(struct gendisk), GFP_KERNEL, node_id);
 	if (disk) {
@@ -1334,7 +1384,8 @@ struct gendisk *alloc_disk_node(int minors, int node_id)
 			kfree(disk);
 			return NULL;
 		}
-		disk->part_tbl->part[0] = &disk->part0;
+		ptbl = rcu_dereference_protected(disk->part_tbl, 1);
+		rcu_assign_pointer(ptbl->part[0], &disk->part0);
 
 		/*
 		 * set_capacity() and get_capacity() currently don't use
diff --git a/block/mq-deadline.c b/block/mq-deadline.c
index 1b964a387afe..a1cad4331edd 100644
--- a/block/mq-deadline.c
+++ b/block/mq-deadline.c
@@ -457,13 +457,12 @@ deadline_var_show(int var, char *page)
 	return sprintf(page, "%d\n", var);
 }
 
-static ssize_t
-deadline_var_store(int *var, const char *page, size_t count)
+static void
+deadline_var_store(int *var, const char *page)
 {
 	char *p = (char *) page;
 
 	*var = simple_strtol(p, &p, 10);
-	return count;
 }
 
 #define SHOW_FUNCTION(__FUNC, __VAR, __CONV)				\
@@ -487,7 +486,7 @@ static ssize_t __FUNC(struct elevator_queue *e, const char *page, size_t count)
 {									\
 	struct deadline_data *dd = e->elevator_data;			\
 	int __data;							\
-	int ret = deadline_var_store(&__data, (page), count);		\
+	deadline_var_store(&__data, (page));				\
 	if (__data < (MIN))						\
 		__data = (MIN);						\
 	else if (__data > (MAX))					\
@@ -496,7 +495,7 @@ static ssize_t __FUNC(struct elevator_queue *e, const char *page, size_t count)
 		*(__PTR) = msecs_to_jiffies(__data);			\
 	else								\
 		*(__PTR) = __data;					\
-	return ret;							\
+	return count;							\
 }
 STORE_FUNCTION(deadline_read_expire_store, &dd->fifo_expire[READ], 0, INT_MAX, 1);
 STORE_FUNCTION(deadline_write_expire_store, &dd->fifo_expire[WRITE], 0, INT_MAX, 1);
@@ -660,6 +659,7 @@ static struct elevator_type mq_deadline = {
 	.elevator_name = "mq-deadline",
 	.elevator_owner = THIS_MODULE,
 };
+MODULE_ALIAS("mq-deadline-iosched");
 
 static int __init deadline_init(void)
 {
diff --git a/block/partition-generic.c b/block/partition-generic.c
index c5ec8246e25e..86e8fe1adcdb 100644
--- a/block/partition-generic.c
+++ b/block/partition-generic.c
@@ -112,11 +112,14 @@ ssize_t part_stat_show(struct device *dev,
 		       struct device_attribute *attr, char *buf)
 {
 	struct hd_struct *p = dev_to_part(dev);
+	struct request_queue *q = dev_to_disk(dev)->queue;
+	unsigned int inflight[2];
 	int cpu;
 
 	cpu = part_stat_lock();
-	part_round_stats(cpu, p);
+	part_round_stats(q, cpu, p);
 	part_stat_unlock();
+	part_in_flight(q, p, inflight);
 	return sprintf(buf,
 		"%8lu %8lu %8llu %8u "
 		"%8lu %8lu %8llu %8u "
@@ -130,7 +133,7 @@ ssize_t part_stat_show(struct device *dev,
 		part_stat_read(p, merges[WRITE]),
 		(unsigned long long)part_stat_read(p, sectors[WRITE]),
 		jiffies_to_msecs(part_stat_read(p, ticks[WRITE])),
-		part_in_flight(p),
+		inflight[0],
 		jiffies_to_msecs(part_stat_read(p, io_ticks)),
 		jiffies_to_msecs(part_stat_read(p, time_in_queue)));
 }
@@ -249,15 +252,20 @@ void __delete_partition(struct percpu_ref *ref)
 	call_rcu(&part->rcu_head, delete_partition_rcu_cb);
 }
 
+/*
+ * Must be called either with bd_mutex held, before a disk can be opened or
+ * after all disk users are gone.
+ */
 void delete_partition(struct gendisk *disk, int partno)
 {
-	struct disk_part_tbl *ptbl = disk->part_tbl;
+	struct disk_part_tbl *ptbl =
+		rcu_dereference_protected(disk->part_tbl, 1);
 	struct hd_struct *part;
 
 	if (partno >= ptbl->len)
 		return;
 
-	part = ptbl->part[partno];
+	part = rcu_dereference_protected(ptbl->part[partno], 1);
 	if (!part)
 		return;
 
@@ -277,6 +285,10 @@ static ssize_t whole_disk_show(struct device *dev,
 static DEVICE_ATTR(whole_disk, S_IRUSR | S_IRGRP | S_IROTH,
 		   whole_disk_show, NULL);
 
+/*
+ * Must be called either with bd_mutex held, before a disk can be opened or
+ * after all disk users are gone.
+ */
 struct hd_struct *add_partition(struct gendisk *disk, int partno,
 				sector_t start, sector_t len, int flags,
 				struct partition_meta_info *info)
@@ -292,7 +304,7 @@ struct hd_struct *add_partition(struct gendisk *disk, int partno,
 	err = disk_expand_part_tbl(disk, partno);
 	if (err)
 		return ERR_PTR(err);
-	ptbl = disk->part_tbl;
+	ptbl = rcu_dereference_protected(disk->part_tbl, 1);
 
 	if (ptbl->part[partno])
 		return ERR_PTR(-EBUSY);
@@ -391,7 +403,6 @@ out_del:
 	device_del(pdev);
 out_put:
 	put_device(pdev);
-	blk_free_devt(devt);
 	return ERR_PTR(err);
 }