diff --git a/block/blk-core.c b/block/blk-core.c
index e0a094fddee5..089e890ab208 100644
--- a/block/blk-core.c
+++ b/block/blk-core.c
@@ -885,11 +885,14 @@ generic_make_request_checks(struct bio *bio)
 	}
 
 	/*
-	 * For a REQ_NOWAIT based request, return -EOPNOTSUPP
-	 * if queue is not a request based queue.
+	 * Non-mq queues do not honor REQ_NOWAIT, so complete a bio
+	 * with BLK_STS_AGAIN status in order to catch -EAGAIN and
+	 * to give a chance to the caller to repeat request gracefully.
 	 */
-	if ((bio->bi_opf & REQ_NOWAIT) && !queue_is_mq(q))
-		goto not_supported;
+	if ((bio->bi_opf & REQ_NOWAIT) && !queue_is_mq(q)) {
+		status = BLK_STS_AGAIN;
+		goto end_io;
+	}
 
 	if (should_fail_bio(bio))
 		goto end_io;
diff --git a/block/blk-flush.c b/block/blk-flush.c
index 1777346baf06..3f977c517960 100644
--- a/block/blk-flush.c
+++ b/block/blk-flush.c
@@ -69,6 +69,7 @@
 #include <linux/blkdev.h>
 #include <linux/gfp.h>
 #include <linux/blk-mq.h>
+#include <linux/lockdep.h>
 
 #include "blk.h"
 #include "blk-mq.h"
@@ -505,6 +506,9 @@ struct blk_flush_queue *blk_alloc_flush_queue(struct request_queue *q,
 	INIT_LIST_HEAD(&fq->flush_queue[1]);
 	INIT_LIST_HEAD(&fq->flush_data_in_flight);
 
+	lockdep_register_key(&fq->key);
+	lockdep_set_class(&fq->mq_flush_lock, &fq->key);
+
 	return fq;
 
  fail_rq:
@@ -519,6 +523,7 @@ void blk_free_flush_queue(struct blk_flush_queue *fq)
 	if (!fq)
 		return;
 
+	lockdep_unregister_key(&fq->key);
 	kfree(fq->flush_rq);
 	kfree(fq);
 }
diff --git a/block/blk-iocost.c b/block/blk-iocost.c
index e01267f99183..27ca68621137 100644
--- a/block/blk-iocost.c
+++ b/block/blk-iocost.c
@@ -1212,7 +1212,7 @@ static enum hrtimer_restart iocg_waitq_timer_fn(struct hrtimer *timer)
 	return HRTIMER_NORESTART;
 }
 
-static void iocg_kick_delay(struct ioc_gq *iocg, struct ioc_now *now, u64 cost)
+static bool iocg_kick_delay(struct ioc_gq *iocg, struct ioc_now *now, u64 cost)
 {
 	struct ioc *ioc = iocg->ioc;
 	struct blkcg_gq *blkg = iocg_to_blkg(iocg);
@@ -1229,11 +1229,11 @@ static void iocg_kick_delay(struct ioc_gq *iocg, struct ioc_now *now, u64 cost)
 	/* clear or maintain depending on the overage */
 	if (time_before_eq64(vtime, now->vnow)) {
 		blkcg_clear_delay(blkg);
-		return;
+		return false;
 	}
 	if (!atomic_read(&blkg->use_delay) &&
 	    time_before_eq64(vtime, now->vnow + vmargin))
-		return;
+		return false;
 
 	/* use delay */
 	if (cost) {
@@ -1250,10 +1250,11 @@ static void iocg_kick_delay(struct ioc_gq *iocg, struct ioc_now *now, u64 cost)
 	oexpires = ktime_to_ns(hrtimer_get_softexpires(&iocg->delay_timer));
 	if (hrtimer_is_queued(&iocg->delay_timer) &&
 	    abs(oexpires - expires) <= margin_ns / 4)
-		return;
+		return true;
 
 	hrtimer_start_range_ns(&iocg->delay_timer, ns_to_ktime(expires),
 			       margin_ns / 4, HRTIMER_MODE_ABS);
+	return true;
 }
 
 static enum hrtimer_restart iocg_delay_timer_fn(struct hrtimer *timer)
@@ -1739,7 +1740,9 @@ static void ioc_rqos_throttle(struct rq_qos *rqos, struct bio *bio)
 	 */
 	if (bio_issue_as_root_blkg(bio) || fatal_signal_pending(current)) {
 		atomic64_add(abs_cost, &iocg->abs_vdebt);
-		iocg_kick_delay(iocg, &now, cost);
+		if (iocg_kick_delay(iocg, &now, cost))
+			blkcg_schedule_throttle(rqos->q,
+					(bio->bi_opf & REQ_SWAP) == REQ_SWAP);
 		return;
 	}
 
diff --git a/block/blk-map.c b/block/blk-map.c
index 3a62e471d81b..b0790268ed9d 100644
--- a/block/blk-map.c
+++ b/block/blk-map.c
@@ -151,7 +151,7 @@ int blk_rq_map_user_iov(struct request_queue *q, struct request *rq,
 	return 0;
 
 unmap_rq:
-	__blk_rq_unmap_user(bio);
+	blk_rq_unmap_user(bio);
 fail:
 	rq->bio = NULL;
 	return ret;
diff --git a/block/blk.h b/block/blk.h
index 6842f28c033e..0b8884353f6b 100644
--- a/block/blk.h
+++ b/block/blk.h
@@ -30,6 +30,7 @@ struct blk_flush_queue {
 	 * at the same time
 	 */
 	struct request		*orig_rq;
+	struct lock_class_key	key;
 	spinlock_t		mq_flush_lock;
 };
 
diff --git a/block/bsg-lib.c b/block/bsg-lib.c
index 347dda16c2f4..6cbb7926534c 100644
--- a/block/bsg-lib.c
+++ b/block/bsg-lib.c
@@ -266,7 +266,7 @@ static blk_status_t bsg_queue_rq(struct blk_mq_hw_ctx *hctx,
 	struct request *req = bd->rq;
 	struct bsg_set *bset =
 		container_of(q->tag_set, struct bsg_set, tag_set);
-	int sts = BLK_STS_IOERR;
+	blk_status_t sts = BLK_STS_IOERR;
 	int ret;
 
 	blk_mq_start_request(req);
diff --git a/drivers/block/nbd.c b/drivers/block/nbd.c
index 57532465fb83..b4607dd96185 100644
--- a/drivers/block/nbd.c
+++ b/drivers/block/nbd.c
@@ -1296,10 +1296,10 @@ static int nbd_start_device_ioctl(struct nbd_device *nbd, struct block_device *b
 	mutex_unlock(&nbd->config_lock);
 	ret = wait_event_interruptible(config->recv_wq,
 					 atomic_read(&config->recv_threads) == 0);
-	if (ret) {
+	if (ret)
 		sock_shutdown(nbd);
-		flush_workqueue(nbd->recv_workq);
-	}
+	flush_workqueue(nbd->recv_workq);
+
 	mutex_lock(&nbd->config_lock);
 	nbd_bdev_reset(bdev);
 	/* user requested, ignore socket errors */
diff --git a/drivers/s390/block/dasd_eckd.c b/drivers/s390/block/dasd_eckd.c
index c94184d080f8..a28b9ff82378 100644
--- a/drivers/s390/block/dasd_eckd.c
+++ b/drivers/s390/block/dasd_eckd.c
@@ -1128,7 +1128,8 @@ static u32 get_fcx_max_data(struct dasd_device *device)
 {
 	struct dasd_eckd_private *private = device->private;
 	int fcx_in_css, fcx_in_gneq, fcx_in_features;
-	int tpm, mdc;
+	unsigned int mdc;
+	int tpm;
 
 	if (dasd_nofcx)
 		return 0;
@@ -1142,7 +1143,7 @@ static u32 get_fcx_max_data(struct dasd_device *device)
 		return 0;
 
 	mdc = ccw_device_get_mdc(device->cdev, 0);
-	if (mdc < 0) {
+	if (mdc == 0) {
 		dev_warn(&device->cdev->dev, "Detecting the maximum supported data size for zHPF requests failed\n");
 		return 0;
 	} else {
@@ -1153,12 +1154,12 @@ static u32 get_fcx_max_data(struct dasd_device *device)
 static int verify_fcx_max_data(struct dasd_device *device, __u8 lpm)
 {
 	struct dasd_eckd_private *private = device->private;
-	int mdc;
+	unsigned int mdc;
 	u32 fcx_max_data;
 
 	if (private->fcx_max_data) {
 		mdc = ccw_device_get_mdc(device->cdev, lpm);
-		if ((mdc < 0)) {
+		if (mdc == 0) {
 			dev_warn(&device->cdev->dev,
 				 "Detecting the maximum data size for zHPF "
 				 "requests failed (rc=%d) for a new path %x\n",
@@ -2073,7 +2074,7 @@ out_err2:
 	dasd_free_block(device->block);
 	device->block = NULL;
 out_err1:
-	kfree(private->conf_data);
+	dasd_eckd_clear_conf_data(device);
 	kfree(device->private);
 	device->private = NULL;
 	return rc;
@@ -2082,7 +2083,6 @@ out_err1:
 static void dasd_eckd_uncheck_device(struct dasd_device *device)
 {
 	struct dasd_eckd_private *private = device->private;
-	int i;
 
 	if (!private)
 		return;
@@ -2092,21 +2092,7 @@ static void dasd_eckd_uncheck_device(struct dasd_device *device)
 	private->sneq = NULL;
 	private->vdsneq = NULL;
 	private->gneq = NULL;
-	private->conf_len = 0;
-	for (i = 0; i < 8; i++) {
-		kfree(device->path[i].conf_data);
-		if ((__u8 *)device->path[i].conf_data ==
-		    private->conf_data) {
-			private->conf_data = NULL;
-			private->conf_len = 0;
-		}
-		device->path[i].conf_data = NULL;
-		device->path[i].cssid = 0;
-		device->path[i].ssid = 0;
-		device->path[i].chpid = 0;
-	}
-	kfree(private->conf_data);
-	private->conf_data = NULL;
+	dasd_eckd_clear_conf_data(device);
 }
 
 static struct dasd_ccw_req *
diff --git a/drivers/s390/block/dasd_fba.h b/drivers/s390/block/dasd_fba.h
index 8f75df06e893..45ddabec4017 100644
--- a/drivers/s390/block/dasd_fba.h
+++ b/drivers/s390/block/dasd_fba.h
@@ -2,7 +2,7 @@
 /*
  * Author(s)......: Holger Smolinski <Holger.Smolinski@de.ibm.com>
  * Bugreports.to..: <Linux390@de.ibm.com>
- * Coypright IBM Corp. 1999, 2000
+ * Copyright IBM Corp. 1999, 2000
  *
  */
 
diff --git a/drivers/s390/block/dasd_proc.c b/drivers/s390/block/dasd_proc.c
index 1770b99f607e..8d4d69ea5baf 100644
--- a/drivers/s390/block/dasd_proc.c
+++ b/drivers/s390/block/dasd_proc.c
@@ -5,7 +5,7 @@
  *		    Carsten Otte <Cotte@de.ibm.com>
  *		    Martin Schwidefsky <schwidefsky@de.ibm.com>
  * Bugreports.to..: <Linux390@de.ibm.com>
- * Coypright IBM Corp. 1999, 2002
+ * Copyright IBM Corp. 1999, 2002
  *
  * /proc interface for the dasd driver.
  *
diff --git a/drivers/s390/cio/device_ops.c b/drivers/s390/cio/device_ops.c
index 65841af15748..ccecf6b9504e 100644
--- a/drivers/s390/cio/device_ops.c
+++ b/drivers/s390/cio/device_ops.c
@@ -635,7 +635,7 @@ EXPORT_SYMBOL(ccw_device_tm_start_timeout);
  * @mask: mask of paths to use
  *
  * Return the number of 64K-bytes blocks all paths at least support
- * for a transport command. Return values <= 0 indicate failures.
+ * for a transport command. Return value 0 indicates failure.
  */
 int ccw_device_get_mdc(struct ccw_device *cdev, u8 mask)
 {
diff --git a/lib/sbitmap.c b/lib/sbitmap.c
index 33feec8989f1..af88d1346dd7 100644
--- a/lib/sbitmap.c
+++ b/lib/sbitmap.c
@@ -650,8 +650,8 @@ void sbitmap_add_wait_queue(struct sbitmap_queue *sbq,
 	if (!sbq_wait->sbq) {
 		sbq_wait->sbq = sbq;
 		atomic_inc(&sbq->ws_active);
+		add_wait_queue(&ws->wait, &sbq_wait->wait);
 	}
-	add_wait_queue(&ws->wait, &sbq_wait->wait);
 }
 EXPORT_SYMBOL_GPL(sbitmap_add_wait_queue);