Linux-libre 4.8.7-gnupck-4.8.7-gnu

15 files changed, 24 insertions, 557 deletions

diff --git a/block/Kconfig b/block/Kconfig
index 6da79e670..161491d0a 100644
--- a/block/Kconfig
+++ b/block/Kconfig
@@ -4,7 +4,6 @@
 menuconfig BLOCK
        bool "Enable the block layer" if EXPERT
        default y
-       select WBT
        help
 	 Provide block layer support for the kernel.
 
diff --git a/block/Kconfig.iosched b/block/Kconfig.iosched
index 6d9257924..277b112b8 100644
--- a/block/Kconfig.iosched
+++ b/block/Kconfig.iosched
@@ -43,13 +43,10 @@ config IOSCHED_BFQ
 	tristate "BFQ I/O scheduler"
 	default n
 	---help---
-	  The BFQ I/O scheduler tries to distribute bandwidth among
-	  all processes according to their weights.
-	  It aims at distributing the bandwidth as desired, independently of
-	  the disk parameters and with any workload. It also tries to
-	  guarantee low latency to interactive and soft real-time
-	  applications. If compiled built-in (saying Y here), BFQ can
-	  be configured to support hierarchical scheduling.
+	The BFQ I/O scheduler distributes bandwidth among all
+	processes according to their weights, regardless of the
+	device parameters and with any workload. It also guarantees
+	a low latency to interactive and soft real-time applications.
 
 config BFQ_GROUP_IOSCHED
 	bool "BFQ hierarchical scheduling support"
diff --git a/block/Makefile b/block/Makefile
index b7aa613b4..4a3668393 100644
--- a/block/Makefile
+++ b/block/Makefile
@@ -5,7 +5,7 @@
 obj-$(CONFIG_BLOCK) := bio.o elevator.o blk-core.o blk-tag.o blk-sysfs.o \
 			blk-flush.o blk-settings.o blk-ioc.o blk-map.o \
 			blk-exec.o blk-merge.o blk-softirq.o blk-timeout.o \
-			blk-lib.o blk-mq.o blk-mq-tag.o blk-stat.o \
+			blk-lib.o blk-mq.o blk-mq-tag.o \
 			blk-mq-sysfs.o blk-mq-cpu.o blk-mq-cpumap.o ioctl.o \
 			genhd.o scsi_ioctl.o partition-generic.o ioprio.o \
 			badblocks.o partitions/
diff --git a/block/bfq-cgroup.c b/block/bfq-cgroup.c
index 569988bda..b50ae8ec6 100644
--- a/block/bfq-cgroup.c
+++ b/block/bfq-cgroup.c
@@ -649,18 +649,6 @@ static void bfq_bic_update_cgroup(struct bfq_io_cq *bic, struct bio *bio)
 	if (unlikely(!bfqd) || likely(bic->blkcg_serial_nr == serial_nr))
 		goto out;
 
-	/*
-	 * If we have a non-root cgroup, we can depend on that to
-	 * do proper throttling of writes. Turn off wbt for that
-	 * case.
-	*/
-	if (bio_blkcg(bio) != &blkcg_root) {
-		struct request_queue *q = bfqd->queue;
-
-		if (q->rq_wb)
-			wbt_disable(q->rq_wb);
-	}
-
 	bfqg = __bfq_bic_change_cgroup(bfqd, bic, bio_blkcg(bio));
 	bic->blkcg_serial_nr = serial_nr;
 out:
diff --git a/block/bfq-iosched.c b/block/bfq-iosched.c
index ecb949ec6..0f3081dbd 100644
--- a/block/bfq-iosched.c
+++ b/block/bfq-iosched.c
@@ -1,5 +1,5 @@
 /*
- * Budget Fair Queueing (BFQ) disk scheduler.
+ * Budget Fair Queueing (BFQ) I/O scheduler.
  *
  * Based on ideas and code from CFQ:
  * Copyright (C) 2003 Jens Axboe <axboe@kernel.dk>
@@ -77,19 +77,19 @@
 static const u64 bfq_fifo_expire[2] = { NSEC_PER_SEC / 4, NSEC_PER_SEC / 8 };
 
 /* Maximum backwards seek, in KiB. */
-static const int bfq_back_max = 16 * 1024;
+static const int bfq_back_max = (16 * 1024);
 
 /* Penalty of a backwards seek, in number of sectors. */
 static const int bfq_back_penalty = 2;
 
 /* Idling period duration, in ns. */
-static u32 bfq_slice_idle = NSEC_PER_SEC / 125;
+static u32 bfq_slice_idle = (NSEC_PER_SEC / 125);
 
 /* Minimum number of assigned budgets for which stats are safe to compute. */
 static const int bfq_stats_min_budgets = 194;
 
 /* Default maximum budget values, in sectors and number of requests. */
-static const int bfq_default_max_budget = 16 * 1024;
+static const int bfq_default_max_budget = (16 * 1024);
 
 /*
  * Async to sync throughput distribution is controlled as follows:
@@ -99,7 +99,7 @@ static const int bfq_default_max_budget = 16 * 1024;
 static const int bfq_async_charge_factor = 10;
 
 /* Default timeout values, in jiffies, approximating CFQ defaults. */
-static const int bfq_timeout = HZ / 8;
+static const int bfq_timeout = (HZ / 8);
 
 struct kmem_cache *bfq_pool;
 
@@ -117,7 +117,7 @@ struct kmem_cache *bfq_pool;
 /* Min number of samples required to perform peak-rate update */
 #define BFQ_RATE_MIN_SAMPLES	32
 /* Min observation time interval required to perform a peak-rate update (ns) */
-#define BFQ_RATE_MIN_INTERVAL	300*NSEC_PER_MSEC
+#define BFQ_RATE_MIN_INTERVAL	(300*NSEC_PER_MSEC)
 /* Target observation time interval for a peak-rate update (ns) */
 #define BFQ_RATE_REF_INTERVAL	NSEC_PER_SEC
 
@@ -2179,9 +2179,13 @@ static void __bfq_set_in_service_queue(struct bfq_data *bfqd,
 			 * not only expires, but also remains with no
 			 * request.
 			 */
-			bfqq->last_wr_start_finish += jiffies -
-				max_t(unsigned long, bfqq->last_wr_start_finish,
-				      bfqq->budget_timeout);
+			if (time_after(bfqq->budget_timeout,
+				       bfqq->last_wr_start_finish))
+				bfqq->last_wr_start_finish +=
+					jiffies - bfqq->budget_timeout;
+			else
+				bfqq->last_wr_start_finish = jiffies;
+
 			if (time_is_after_jiffies(bfqq->last_wr_start_finish)) {
 			       pr_crit(
 			       "BFQ WARNING:last %lu budget %lu jiffies %lu",
@@ -5208,7 +5212,7 @@ static struct blkcg_policy blkcg_policy_bfq = {
 static int __init bfq_init(void)
 {
 	int ret;
-	char msg[50] = "BFQ I/O-scheduler: v8r4";
+	char msg[50] = "BFQ I/O-scheduler: v8r5";
 
 #ifdef CONFIG_BFQ_GROUP_IOSCHED
 	ret = blkcg_policy_register(&blkcg_policy_bfq);
diff --git a/block/bfq.h b/block/bfq.h
index ea1e7d852..b80abe0e3 100644
--- a/block/bfq.h
+++ b/block/bfq.h
@@ -1,5 +1,5 @@
 /*
- * BFQ-v8r4 for 4.8.0: data structures and common functions prototypes.
+ * BFQ-v8r5 for 4.8.0: data structures and common functions prototypes.
  *
  * Based on ideas and code from CFQ:
  * Copyright (C) 2003 Jens Axboe <axboe@kernel.dk>
diff --git a/block/blk-core.c b/block/blk-core.c
index cdcb188e8..36c7ac328 100644
--- a/block/blk-core.c
+++ b/block/blk-core.c
@@ -33,7 +33,6 @@
 #include <linux/ratelimit.h>
 #include <linux/pm_runtime.h>
 #include <linux/blk-cgroup.h>
-#include <linux/wbt.h>
 
 #define CREATE_TRACE_POINTS
 #include <trace/events/block.h>
@@ -883,8 +882,6 @@ blk_init_allocated_queue(struct request_queue *q, request_fn_proc *rfn,
 
 fail:
 	blk_free_flush_queue(q->fq);
-	wbt_exit(q->rq_wb);
-	q->rq_wb = NULL;
 	return NULL;
 }
 EXPORT_SYMBOL(blk_init_allocated_queue);
@@ -1349,7 +1346,6 @@ void blk_requeue_request(struct request_queue *q, struct request *rq)
 	blk_delete_timer(rq);
 	blk_clear_rq_complete(rq);
 	trace_block_rq_requeue(q, rq);
-	wbt_requeue(q->rq_wb, &rq->wb_stat);
 
 	if (rq->cmd_flags & REQ_QUEUED)
 		blk_queue_end_tag(q, rq);
@@ -1440,8 +1436,6 @@ void __blk_put_request(struct request_queue *q, struct request *req)
 	/* this is a bio leak */
 	WARN_ON(req->bio != NULL);
 
-	wbt_done(q->rq_wb, &req->wb_stat);
-
 	/*
 	 * Request may not have originated from ll_rw_blk. if not,
 	 * it didn't come out of our reserved rq pools
@@ -1673,7 +1667,6 @@ static blk_qc_t blk_queue_bio(struct request_queue *q, struct bio *bio)
 	int el_ret, rw_flags = 0, where = ELEVATOR_INSERT_SORT;
 	struct request *req;
 	unsigned int request_count = 0;
-	unsigned int wb_acct;
 
 	/*
 	 * low level driver can indicate that it wants pages above a
@@ -1726,8 +1719,6 @@ static blk_qc_t blk_queue_bio(struct request_queue *q, struct bio *bio)
 	}
 
 get_rq:
-	wb_acct = wbt_wait(q->rq_wb, bio->bi_opf, q->queue_lock);
-
 	/*
 	 * This sync check and mask will be re-done in init_request_from_bio(),
 	 * but we need to set it earlier to expose the sync flag to the
@@ -1747,14 +1738,11 @@ get_rq:
 	 */
 	req = get_request(q, bio_data_dir(bio), rw_flags, bio, GFP_NOIO);
 	if (IS_ERR(req)) {
-		__wbt_done(q->rq_wb, wb_acct);
 		bio->bi_error = PTR_ERR(req);
 		bio_endio(bio);
 		goto out_unlock;
 	}
 
-	wbt_track(&req->wb_stat, wb_acct);
-
 	/*
 	 * After dropping the lock and possibly sleeping here, our request
 	 * may now be mergeable after it had proven unmergeable (above).
@@ -2487,8 +2475,6 @@ void blk_start_request(struct request *req)
 {
 	blk_dequeue_request(req);
 
-	wbt_issue(req->q->rq_wb, &req->wb_stat);
-
 	/*
 	 * We are now handing the request to the hardware, initialize
 	 * resid_len to full count and add the timeout handler.
@@ -2556,8 +2542,6 @@ bool blk_update_request(struct request *req, int error, unsigned int nr_bytes)
 
 	trace_block_rq_complete(req->q, req, nr_bytes);
 
-	blk_stat_add(&req->q->rq_stats[rq_data_dir(req)], req);
-
 	if (!req->bio)
 		return false;
 
@@ -2725,10 +2709,9 @@ void blk_finish_request(struct request *req, int error)
 
 	blk_account_io_done(req);
 
-	if (req->end_io) {
-		wbt_done(req->q->rq_wb, &req->wb_stat);
+	if (req->end_io)
 		req->end_io(req, error);
-	} else {
+	else {
 		if (blk_bidi_rq(req))
 			__blk_put_request(req->next_rq->q, req->next_rq);
 
diff --git a/block/blk-mq-sysfs.c b/block/blk-mq-sysfs.c
index b66bbf13c..fe822aa5b 100644
--- a/block/blk-mq-sysfs.c
+++ b/block/blk-mq-sysfs.c
@@ -247,47 +247,6 @@ static ssize_t blk_mq_hw_sysfs_cpus_show(struct blk_mq_hw_ctx *hctx, char *page)
 	return ret;
 }
 
-static void blk_mq_stat_clear(struct blk_mq_hw_ctx *hctx)
-{
-	struct blk_mq_ctx *ctx;
-	unsigned int i;
-
-	hctx_for_each_ctx(hctx, ctx, i) {
-		blk_stat_init(&ctx->stat[0]);
-		blk_stat_init(&ctx->stat[1]);
-	}
-}
-
-static ssize_t blk_mq_hw_sysfs_stat_store(struct blk_mq_hw_ctx *hctx,
-					  const char *page, size_t count)
-{
-	blk_mq_stat_clear(hctx);
-	return count;
-}
-
-static ssize_t print_stat(char *page, struct blk_rq_stat *stat, const char *pre)
-{
-	return sprintf(page, "%s samples=%llu, mean=%lld, min=%lld, max=%lld\n",
-			pre, (long long) stat->nr_samples,
-			(long long) stat->mean, (long long) stat->min,
-			(long long) stat->max);
-}
-
-static ssize_t blk_mq_hw_sysfs_stat_show(struct blk_mq_hw_ctx *hctx, char *page)
-{
-	struct blk_rq_stat stat[2];
-	ssize_t ret;
-
-	blk_stat_init(&stat[0]);
-	blk_stat_init(&stat[1]);
-
-	blk_hctx_stat_get(hctx, stat);
-
-	ret = print_stat(page, &stat[0], "read :");
-	ret += print_stat(page + ret, &stat[1], "write:");
-	return ret;
-}
-
 static struct blk_mq_ctx_sysfs_entry blk_mq_sysfs_dispatched = {
 	.attr = {.name = "dispatched", .mode = S_IRUGO },
 	.show = blk_mq_sysfs_dispatched_show,
@@ -345,11 +304,6 @@ static struct blk_mq_hw_ctx_sysfs_entry blk_mq_hw_sysfs_poll = {
 	.attr = {.name = "io_poll", .mode = S_IRUGO },
 	.show = blk_mq_hw_sysfs_poll_show,
 };
-static struct blk_mq_hw_ctx_sysfs_entry blk_mq_hw_sysfs_stat = {
-	.attr = {.name = "stats", .mode = S_IRUGO | S_IWUSR },
-	.show = blk_mq_hw_sysfs_stat_show,
-	.store = blk_mq_hw_sysfs_stat_store,
-};
 
 static struct attribute *default_hw_ctx_attrs[] = {
 	&blk_mq_hw_sysfs_queued.attr,
@@ -360,7 +314,6 @@ static struct attribute *default_hw_ctx_attrs[] = {
 	&blk_mq_hw_sysfs_cpus.attr,
 	&blk_mq_hw_sysfs_active.attr,
 	&blk_mq_hw_sysfs_poll.attr,
-	&blk_mq_hw_sysfs_stat.attr,
 	NULL,
 };
 
diff --git a/block/blk-mq.c b/block/blk-mq.c
index 815e2ac02..c207fa987 100644
--- a/block/blk-mq.c
+++ b/block/blk-mq.c
@@ -22,7 +22,6 @@
 #include <linux/sched/sysctl.h>
 #include <linux/delay.h>
 #include <linux/crash_dump.h>
-#include <linux/wbt.h>
 
 #include <trace/events/block.h>
 
@@ -30,7 +29,6 @@
 #include "blk.h"
 #include "blk-mq.h"
 #include "blk-mq-tag.h"
-#include "blk-stat.h"
 
 static DEFINE_MUTEX(all_q_mutex);
 static LIST_HEAD(all_q_list);
@@ -332,8 +330,6 @@ static void __blk_mq_free_request(struct blk_mq_hw_ctx *hctx,
 
 	if (rq->cmd_flags & REQ_MQ_INFLIGHT)
 		atomic_dec(&hctx->nr_active);
-
-	wbt_done(q->rq_wb, &rq->wb_stat);
 	rq->cmd_flags = 0;
 
 	clear_bit(REQ_ATOM_STARTED, &rq->atomic_flags);
@@ -366,7 +362,6 @@ inline void __blk_mq_end_request(struct request *rq, int error)
 	blk_account_io_done(rq);
 
 	if (rq->end_io) {
-		wbt_done(rq->q->rq_wb, &rq->wb_stat);
 		rq->end_io(rq, error);
 	} else {
 		if (unlikely(blk_bidi_rq(rq)))
@@ -417,19 +412,10 @@ static void blk_mq_ipi_complete_request(struct request *rq)
 	put_cpu();
 }
 
-static void blk_mq_stat_add(struct request *rq)
-{
-	struct blk_rq_stat *stat = &rq->mq_ctx->stat[rq_data_dir(rq)];
-
-	blk_stat_add(stat, rq);
-}
-
 static void __blk_mq_complete_request(struct request *rq)
 {
 	struct request_queue *q = rq->q;
 
-	blk_mq_stat_add(rq);
-
 	if (!q->softirq_done_fn)
 		blk_mq_end_request(rq, rq->errors);
 	else
@@ -473,8 +459,6 @@ void blk_mq_start_request(struct request *rq)
 	if (unlikely(blk_bidi_rq(rq)))
 		rq->next_rq->resid_len = blk_rq_bytes(rq->next_rq);
 
-	wbt_issue(q->rq_wb, &rq->wb_stat);
-
 	blk_add_timer(rq);
 
 	/*
@@ -510,7 +494,6 @@ static void __blk_mq_requeue_request(struct request *rq)
 	struct request_queue *q = rq->q;
 
 	trace_block_rq_requeue(q, rq);
-	wbt_requeue(q->rq_wb, &rq->wb_stat);
 
 	if (test_and_clear_bit(REQ_ATOM_STARTED, &rq->atomic_flags)) {
 		if (q->dma_drain_size && blk_rq_bytes(rq))
@@ -1329,7 +1312,6 @@ static blk_qc_t blk_mq_make_request(struct request_queue *q, struct bio *bio)
 	struct blk_plug *plug;
 	struct request *same_queue_rq = NULL;
 	blk_qc_t cookie;
-	unsigned int wb_acct;
 
 	blk_queue_bounce(q, &bio);
 
@@ -1344,15 +1326,9 @@ static blk_qc_t blk_mq_make_request(struct request_queue *q, struct bio *bio)
 	    blk_attempt_plug_merge(q, bio, &request_count, &same_queue_rq))
 		return BLK_QC_T_NONE;
 
-	wb_acct = wbt_wait(q->rq_wb, bio->bi_opf, NULL);
-
 	rq = blk_mq_map_request(q, bio, &data);
-	if (unlikely(!rq)) {
-		__wbt_done(q->rq_wb, wb_acct);
+	if (unlikely(!rq))
 		return BLK_QC_T_NONE;
-	}
-
-	wbt_track(&rq->wb_stat, wb_acct);
 
 	cookie = blk_tag_to_qc_t(rq->tag, data.hctx->queue_num);
 
@@ -1429,7 +1405,6 @@ static blk_qc_t blk_sq_make_request(struct request_queue *q, struct bio *bio)
 	struct blk_map_ctx data;
 	struct request *rq;
 	blk_qc_t cookie;
-	unsigned int wb_acct;
 
 	blk_queue_bounce(q, &bio);
 
@@ -1446,15 +1421,9 @@ static blk_qc_t blk_sq_make_request(struct request_queue *q, struct bio *bio)
 	} else
 		request_count = blk_plug_queued_count(q);
 
-	wb_acct = wbt_wait(q->rq_wb, bio->bi_opf, NULL);
-
 	rq = blk_mq_map_request(q, bio, &data);
-	if (unlikely(!rq)) {
-		__wbt_done(q->rq_wb, wb_acct);
+	if (unlikely(!rq))
 		return BLK_QC_T_NONE;
-	}
-
-	wbt_track(&rq->wb_stat, wb_acct);
 
 	cookie = blk_tag_to_qc_t(rq->tag, data.hctx->queue_num);
 
@@ -1838,8 +1807,6 @@ static void blk_mq_init_cpu_queues(struct request_queue *q,
 		spin_lock_init(&__ctx->lock);
 		INIT_LIST_HEAD(&__ctx->rq_list);
 		__ctx->queue = q;
-		blk_stat_init(&__ctx->stat[0]);
-		blk_stat_init(&__ctx->stat[1]);
 
 		/* If the cpu isn't online, the cpu is mapped to first hctx */
 		if (!cpu_online(i))
@@ -2178,9 +2145,6 @@ void blk_mq_free_queue(struct request_queue *q)
 	list_del_init(&q->all_q_node);
 	mutex_unlock(&all_q_mutex);
 
-	wbt_exit(q->rq_wb);
-	q->rq_wb = NULL;
-
 	blk_mq_del_queue_tag_set(q);
 
 	blk_mq_exit_hw_queues(q, set, set->nr_hw_queues);
diff --git a/block/blk-mq.h b/block/blk-mq.h
index e107f700f..9087b1103 100644
--- a/block/blk-mq.h
+++ b/block/blk-mq.h
@@ -1,8 +1,6 @@
 #ifndef INT_BLK_MQ_H
 #define INT_BLK_MQ_H
 
-#include "blk-stat.h"
-
 struct blk_mq_tag_set;
 
 struct blk_mq_ctx {
@@ -22,7 +20,6 @@ struct blk_mq_ctx {
 
 	/* incremented at completion time */
 	unsigned long		____cacheline_aligned_in_smp rq_completed[2];
-	struct blk_rq_stat	stat[2];
 
 	struct request_queue	*queue;
 	struct kobject		kobj;
diff --git a/block/blk-settings.c b/block/blk-settings.c
index 746dc9fee..f679ae122 100644
--- a/block/blk-settings.c
+++ b/block/blk-settings.c
@@ -832,19 +832,6 @@ void blk_queue_flush_queueable(struct request_queue *q, bool queueable)
 EXPORT_SYMBOL_GPL(blk_queue_flush_queueable);
 
 /**
- * blk_set_queue_depth - tell the block layer about the device queue depth
- * @q:		the request queue for the device
- * @depth:		queue depth
- *
- */
-void blk_set_queue_depth(struct request_queue *q, unsigned int depth)
-{
-	q->queue_depth = depth;
-	wbt_set_queue_depth(q->rq_wb, depth);
-}
-EXPORT_SYMBOL(blk_set_queue_depth);
-
-/**
  * blk_queue_write_cache - configure queue's write cache
  * @q:		the request queue for the device
  * @wc:		write back cache on or off
@@ -864,8 +851,6 @@ void blk_queue_write_cache(struct request_queue *q, bool wc, bool fua)
 	else
 		queue_flag_clear(QUEUE_FLAG_FUA, q);
 	spin_unlock_irq(q->queue_lock);
-
-	wbt_set_write_cache(q->rq_wb, test_bit(QUEUE_FLAG_WC, &q->queue_flags));
 }
 EXPORT_SYMBOL_GPL(blk_queue_write_cache);
 
diff --git a/block/blk-stat.c b/block/blk-stat.c
deleted file mode 100644
index bdb16d84b..000000000
--- a/block/blk-stat.c
+++ /dev/null
@@ -1,221 +0,0 @@
-/*
- * Block stat tracking code
- *
- * Copyright (C) 2016 Jens Axboe
- */
-#include <linux/kernel.h>
-#include <linux/blk-mq.h>
-
-#include "blk-stat.h"
-#include "blk-mq.h"
-
-static void blk_stat_flush_batch(struct blk_rq_stat *stat)
-{
-	if (!stat->nr_batch)
-		return;
-	if (!stat->nr_samples)
-		stat->mean = div64_s64(stat->batch, stat->nr_batch);
-	else {
-		stat->mean = div64_s64((stat->mean * stat->nr_samples) +
-					stat->batch,
-					stat->nr_samples + stat->nr_batch);
-	}
-
-	stat->nr_samples += stat->nr_batch;
-	stat->nr_batch = stat->batch = 0;
-}
-
-void blk_stat_sum(struct blk_rq_stat *dst, struct blk_rq_stat *src)
-{
-	if (!src->nr_samples)
-		return;
-
-	blk_stat_flush_batch(src);
-
-	dst->min = min(dst->min, src->min);
-	dst->max = max(dst->max, src->max);
-
-	if (!dst->nr_samples)
-		dst->mean = src->mean;
-	else {
-		dst->mean = div64_s64((src->mean * src->nr_samples) +
-					(dst->mean * dst->nr_samples),
-					dst->nr_samples + src->nr_samples);
-	}
-	dst->nr_samples += src->nr_samples;
-}
-
-static void blk_mq_stat_get(struct request_queue *q, struct blk_rq_stat *dst)
-{
-	struct blk_mq_hw_ctx *hctx;
-	struct blk_mq_ctx *ctx;
-	uint64_t latest = 0;
-	int i, j, nr;
-
-	blk_stat_init(&dst[0]);
-	blk_stat_init(&dst[1]);
-
-	nr = 0;
-	do {
-		uint64_t newest = 0;
-
-		queue_for_each_hw_ctx(q, hctx, i) {
-			hctx_for_each_ctx(hctx, ctx, j) {
-				if (!ctx->stat[0].nr_samples &&
-				    !ctx->stat[1].nr_samples)
-					continue;
-				if (ctx->stat[0].time > newest)
-					newest = ctx->stat[0].time;
-				if (ctx->stat[1].time > newest)
-					newest = ctx->stat[1].time;
-			}
-		}
-
-		/*
-		 * No samples
-		 */
-		if (!newest)
-			break;
-
-		if (newest > latest)
-			latest = newest;
-
-		queue_for_each_hw_ctx(q, hctx, i) {
-			hctx_for_each_ctx(hctx, ctx, j) {
-				if (ctx->stat[0].time == newest) {
-					blk_stat_sum(&dst[0], &ctx->stat[0]);
-					nr++;
-				}
-				if (ctx->stat[1].time == newest) {
-					blk_stat_sum(&dst[1], &ctx->stat[1]);
-					nr++;
-				}
-			}
-		}
-		/*
-		 * If we race on finding an entry, just loop back again.
-		 * Should be very rare.
-		 */
-	} while (!nr);
-
-	dst[0].time = dst[1].time = latest;
-}
-
-void blk_queue_stat_get(struct request_queue *q, struct blk_rq_stat *dst)
-{
-	if (q->mq_ops)
-		blk_mq_stat_get(q, dst);
-	else {
-		memcpy(&dst[0], &q->rq_stats[0], sizeof(struct blk_rq_stat));
-		memcpy(&dst[1], &q->rq_stats[1], sizeof(struct blk_rq_stat));
-	}
-}
-
-void blk_hctx_stat_get(struct blk_mq_hw_ctx *hctx, struct blk_rq_stat *dst)
-{
-	struct blk_mq_ctx *ctx;
-	unsigned int i, nr;
-
-	nr = 0;
-	do {
-		uint64_t newest = 0;
-
-		hctx_for_each_ctx(hctx, ctx, i) {
-			if (!ctx->stat[0].nr_samples &&
-			    !ctx->stat[1].nr_samples)
-				continue;
-
-			if (ctx->stat[0].time > newest)
-				newest = ctx->stat[0].time;
-			if (ctx->stat[1].time > newest)
-				newest = ctx->stat[1].time;
-		}
-
-		if (!newest)
-			break;
-
-		hctx_for_each_ctx(hctx, ctx, i) {
-			if (ctx->stat[0].time == newest) {
-				blk_stat_sum(&dst[0], &ctx->stat[0]);
-				nr++;
-			}
-			if (ctx->stat[1].time == newest) {
-				blk_stat_sum(&dst[1], &ctx->stat[1]);
-				nr++;
-			}
-		}
-		/*
-		 * If we race on finding an entry, just loop back again.
-		 * Should be very rare, as the window is only updated
-		 * occasionally
-		 */
-	} while (!nr);
-}
-
-static void __blk_stat_init(struct blk_rq_stat *stat, s64 time_now)
-{
-	stat->min = -1ULL;
-	stat->max = stat->nr_samples = stat->mean = 0;
-	stat->batch = stat->nr_batch = 0;
-	stat->time = time_now & BLK_STAT_MASK;
-}
-
-void blk_stat_init(struct blk_rq_stat *stat)
-{
-	__blk_stat_init(stat, ktime_to_ns(ktime_get()));
-}
-
-static bool __blk_stat_is_current(struct blk_rq_stat *stat, s64 now)
-{
-	return (now & BLK_STAT_MASK) == (stat->time & BLK_STAT_MASK);
-}
-
-bool blk_stat_is_current(struct blk_rq_stat *stat)
-{
-	return __blk_stat_is_current(stat, ktime_to_ns(ktime_get()));
-}
-
-void blk_stat_add(struct blk_rq_stat *stat, struct request *rq)
-{
-	s64 now, value;
-	u64 rq_time = wbt_issue_stat_get_time(&rq->wb_stat);
-
-	now = ktime_to_ns(ktime_get());
-	if (now < rq_time)
-		return;
-
-	if (!__blk_stat_is_current(stat, now))
-		__blk_stat_init(stat, now);
-
-	value = now - rq_time;
-	if (value > stat->max)
-		stat->max = value;
-	if (value < stat->min)
-		stat->min = value;
-
-	if (stat->batch + value < stat->batch ||
-	    stat->nr_batch + 1 == BLK_RQ_STAT_BATCH)
-		blk_stat_flush_batch(stat);
-
-	stat->batch += value;
-	stat->nr_batch++;
-}
-
-void blk_stat_clear(struct request_queue *q)
-{
-	if (q->mq_ops) {
-		struct blk_mq_hw_ctx *hctx;
-		struct blk_mq_ctx *ctx;
-		int i, j;
-
-		queue_for_each_hw_ctx(q, hctx, i) {
-			hctx_for_each_ctx(hctx, ctx, j) {
-				blk_stat_init(&ctx->stat[0]);
-				blk_stat_init(&ctx->stat[1]);
-			}
-		}
-	} else {
-		blk_stat_init(&q->rq_stats[0]);
-		blk_stat_init(&q->rq_stats[1]);
-	}
-}
diff --git a/block/blk-stat.h b/block/blk-stat.h
deleted file mode 100644
index 376a6ccd9..000000000
--- a/block/blk-stat.h
+++ /dev/null
@@ -1,18 +0,0 @@
-#ifndef BLK_STAT_H
-#define BLK_STAT_H
-
-/*
- * ~0.13s window as a power-of-2 (2^27 nsecs)
- */
-#define BLK_STAT_NSEC	134217728ULL
-#define BLK_STAT_MASK	~(BLK_STAT_NSEC - 1)
-
-void blk_stat_add(struct blk_rq_stat *, struct request *);
-void blk_hctx_stat_get(struct blk_mq_hw_ctx *, struct blk_rq_stat *);
-void blk_queue_stat_get(struct request_queue *, struct blk_rq_stat *);
-void blk_stat_clear(struct request_queue *q);
-void blk_stat_init(struct blk_rq_stat *);
-void blk_stat_sum(struct blk_rq_stat *, struct blk_rq_stat *);
-bool blk_stat_is_current(struct blk_rq_stat *);
-
-#endif
diff --git a/block/blk-sysfs.c b/block/blk-sysfs.c
index 85c3dc223..f87a7e747 100644
--- a/block/blk-sysfs.c
+++ b/block/blk-sysfs.c
@@ -10,7 +10,6 @@
 #include <linux/blktrace_api.h>
 #include <linux/blk-mq.h>
 #include <linux/blk-cgroup.h>
-#include <linux/wbt.h>
 
 #include "blk.h"
 #include "blk-mq.h"
@@ -42,19 +41,6 @@ queue_var_store(unsigned long *var, const char *page, size_t count)
 	return count;
 }
 
-static ssize_t queue_var_store64(u64 *var, const char *page)
-{
-	int err;
-	u64 v;
-
-	err = kstrtou64(page, 10, &v);
-	if (err < 0)
-		return err;
-
-	*var = v;
-	return 0;
-}
-
 static ssize_t queue_requests_show(struct request_queue *q, char *page)
 {
 	return queue_var_show(q->nr_requests, (page));
@@ -361,58 +347,6 @@ static ssize_t queue_poll_store(struct request_queue *q, const char *page,
 	return ret;
 }
 
-static ssize_t queue_wb_win_show(struct request_queue *q, char *page)
-{
-	if (!q->rq_wb)
-		return -EINVAL;
-
-	return sprintf(page, "%llu\n", div_u64(q->rq_wb->win_nsec, 1000));
-}
-
-static ssize_t queue_wb_win_store(struct request_queue *q, const char *page,
-				  size_t count)
-{
-	ssize_t ret;
-	u64 val;
-
-	if (!q->rq_wb)
-		return -EINVAL;
-
-	ret = queue_var_store64(&val, page);
-	if (ret < 0)
-		return ret;
-
-	q->rq_wb->win_nsec = val * 1000ULL;
-	wbt_update_limits(q->rq_wb);
-	return count;
-}
-
-static ssize_t queue_wb_lat_show(struct request_queue *q, char *page)
-{
-	if (!q->rq_wb)
-		return -EINVAL;
-
-	return sprintf(page, "%llu\n", div_u64(q->rq_wb->min_lat_nsec, 1000));
-}
-
-static ssize_t queue_wb_lat_store(struct request_queue *q, const char *page,
-				  size_t count)
-{
-	ssize_t ret;
-	u64 val;
-
-	if (!q->rq_wb)
-		return -EINVAL;
-
-	ret = queue_var_store64(&val, page);
-	if (ret < 0)
-		return ret;
-
-	q->rq_wb->min_lat_nsec = val * 1000ULL;
-	wbt_update_limits(q->rq_wb);
-	return count;
-}
-
 static ssize_t queue_wc_show(struct request_queue *q, char *page)
 {
 	if (test_bit(QUEUE_FLAG_WC, &q->queue_flags))
@@ -450,26 +384,6 @@ static ssize_t queue_dax_show(struct request_queue *q, char *page)
 	return queue_var_show(blk_queue_dax(q), page);
 }
 
-static ssize_t print_stat(char *page, struct blk_rq_stat *stat, const char *pre)
-{
-	return sprintf(page, "%s samples=%llu, mean=%lld, min=%lld, max=%lld\n",
-			pre, (long long) stat->nr_samples,
-			(long long) stat->mean, (long long) stat->min,
-			(long long) stat->max);
-}
-
-static ssize_t queue_stats_show(struct request_queue *q, char *page)
-{
-	struct blk_rq_stat stat[2];
-	ssize_t ret;
-
-	blk_queue_stat_get(q, stat);
-
-	ret = print_stat(page, &stat[0], "read :");
-	ret += print_stat(page + ret, &stat[1], "write:");
-	return ret;
-}
-
 static struct queue_sysfs_entry queue_requests_entry = {
 	.attr = {.name = "nr_requests", .mode = S_IRUGO | S_IWUSR },
 	.show = queue_requests_show,
@@ -612,23 +526,6 @@ static struct queue_sysfs_entry queue_dax_entry = {
 	.show = queue_dax_show,
 };
 
-static struct queue_sysfs_entry queue_stats_entry = {
-	.attr = {.name = "stats", .mode = S_IRUGO },
-	.show = queue_stats_show,
-};
-
-static struct queue_sysfs_entry queue_wb_lat_entry = {
-	.attr = {.name = "wbt_lat_usec", .mode = S_IRUGO | S_IWUSR },
-	.show = queue_wb_lat_show,
-	.store = queue_wb_lat_store,
-};
-
-static struct queue_sysfs_entry queue_wb_win_entry = {
-	.attr = {.name = "wbt_window_usec", .mode = S_IRUGO | S_IWUSR },
-	.show = queue_wb_win_show,
-	.store = queue_wb_win_store,
-};
-
 static struct attribute *default_attrs[] = {
 	&queue_requests_entry.attr,
 	&queue_ra_entry.attr,
@@ -656,9 +553,6 @@ static struct attribute *default_attrs[] = {
 	&queue_poll_entry.attr,
 	&queue_wc_entry.attr,
 	&queue_dax_entry.attr,
-	&queue_stats_entry.attr,
-	&queue_wb_lat_entry.attr,
-	&queue_wb_win_entry.attr,
 	NULL,
 };
 
@@ -773,49 +667,6 @@ struct kobj_type blk_queue_ktype = {
 	.release	= blk_release_queue,
 };
 
-static void blk_wb_stat_get(void *data, struct blk_rq_stat *stat)
-{
-	blk_queue_stat_get(data, stat);
-}
-
-static void blk_wb_stat_clear(void *data)
-{
-	blk_stat_clear(data);
-}
-
-static bool blk_wb_stat_is_current(struct blk_rq_stat *stat)
-{
-	return blk_stat_is_current(stat);
-}
-
-static struct wb_stat_ops wb_stat_ops = {
-	.get		= blk_wb_stat_get,
-	.is_current	= blk_wb_stat_is_current,
-	.clear		= blk_wb_stat_clear,
-};
-
-static void blk_wb_init(struct request_queue *q)
-{
-	struct rq_wb *rwb;
-
-	rwb = wbt_init(&q->backing_dev_info, &wb_stat_ops, q);
-
-	/*
-	 * If this fails, we don't get throttling
-	 */
-	if (IS_ERR(rwb))
-		return;
-
-	if (blk_queue_nonrot(q))
-		rwb->min_lat_nsec = 2000000ULL;
-	else
-		rwb->min_lat_nsec = 75000000ULL;
-
-	wbt_set_queue_depth(rwb, blk_queue_depth(q));
-	wbt_set_write_cache(rwb, test_bit(QUEUE_FLAG_WC, &q->queue_flags));
-	q->rq_wb = rwb;
-}
-
 int blk_register_queue(struct gendisk *disk)
 {
 	int ret;
@@ -855,8 +706,6 @@ int blk_register_queue(struct gendisk *disk)
 	if (q->mq_ops)
 		blk_mq_register_disk(disk);
 
-	blk_wb_init(q);
-
 	if (!q->request_fn)
 		return 0;
 
diff --git a/block/cfq-iosched.c b/block/cfq-iosched.c
index f336dcbed..5e24d8803 100644
--- a/block/cfq-iosched.c
+++ b/block/cfq-iosched.c
@@ -3771,11 +3771,9 @@ static void check_blkcg_changed(struct cfq_io_cq *cic, struct bio *bio)
 	struct cfq_data *cfqd = cic_to_cfqd(cic);
 	struct cfq_queue *cfqq;
 	uint64_t serial_nr;
-	bool nonroot_cg;
 
 	rcu_read_lock();
 	serial_nr = bio_blkcg(bio)->css.serial_nr;
-	nonroot_cg = bio_blkcg(bio) != &blkcg_root;
 	rcu_read_unlock();
 
 	/*
@@ -3786,17 +3784,6 @@ static void check_blkcg_changed(struct cfq_io_cq *cic, struct bio *bio)
 		return;
 
 	/*
-	 * If we have a non-root cgroup, we can depend on that to
-	 * do proper throttling of writes. Turn off wbt for that
-	 * case.
-	 */
-	if (nonroot_cg) {
-		struct request_queue *q = cfqd->queue;
-
-		wbt_disable(q->rq_wb);
-	}
-
-	/*
 	 * Drop reference to queues.  New queues will be assigned in new
 	 * group upon arrival of fresh requests.
 	 */