Merge branch 'block-5.7' into for-5.8/block

Pull in block-5.7 fixes for 5.8. Mostly to resolve a conflict with
the blk-iocost changes, but we also need the base of the bdi
use-after-free as well as we build on top of it.

* block-5.7:
  nvme: fix possible hang when ns scanning fails during error recovery
  nvme-pci: fix "slimmer CQ head update"
  bdi: add a ->dev_name field to struct backing_dev_info
  bdi: use bdi_dev_name() to get device name
  bdi: move bdi_dev_name out of line
  vboxsf: don't use the source name in the bdi name
  iocost: protect iocg->abs_vdebt with iocg->waitq.lock
  block: remove the bd_openers checks in blk_drop_partitions
  nvme: prevent double free in nvme_alloc_ns() error handling
  null_blk: Cleanup zoned device initialization
  null_blk: Fix zoned command handling
  block: remove unused header
  blk-iocost: Fix error on iocost_ioc_vrate_adj
  bdev: Reduce time holding bd_mutex in sync in blkdev_close()
  buffer: remove useless comment and WB_REASON_FREE_MORE_MEM, reason.
Signed-off-by: Jens Axboe <axboe@kernel.dk>

block/bfq-iosched.c

@@ -123,6 +123,7 @@
 #include <linux/ioprio.h>
 #include <linux/sbitmap.h>
 #include <linux/delay.h>
+#include <linux/backing-dev.h>
 
 #include "blk.h"
 #include "blk-mq.h"
@@ -4976,8 +4977,9 @@ bfq_set_next_ioprio_data(struct bfq_queue *bfqq, struct bfq_io_cq *bic)
 	ioprio_class = IOPRIO_PRIO_CLASS(bic->ioprio);
 	switch (ioprio_class) {
 	default:
-		dev_err(bfqq->bfqd->queue->backing_dev_info->dev,
-			"bfq: bad prio class %d\n", ioprio_class);
+		pr_err("bdi %s: bfq: bad prio class %d\n",
+				bdi_dev_name(bfqq->bfqd->queue->backing_dev_info),
+				ioprio_class);
 		/* fall through */
 	case IOPRIO_CLASS_NONE:
 		/*

block/blk-cgroup.c

@@ -496,7 +496,7 @@ const char *blkg_dev_name(struct blkcg_gq *blkg)
 {
 	/* some drivers (floppy) instantiate a queue w/o disk registered */
 	if (blkg->q->backing_dev_info->dev)
-		return dev_name(blkg->q->backing_dev_info->dev);
+		return bdi_dev_name(blkg->q->backing_dev_info);
 	return NULL;
 }
 

block/blk-iocost.c

@@ -467,7 +467,7 @@ struct ioc_gq {
 	 */
 	atomic64_t			vtime;
 	atomic64_t			done_vtime;
-	atomic64_t			abs_vdebt;
+	u64				abs_vdebt;
 	u64				last_vtime;
 
 	/*
@@ -1143,7 +1143,7 @@ static void iocg_kick_waitq(struct ioc_gq *iocg, struct ioc_now *now)
 	struct iocg_wake_ctx ctx = { .iocg = iocg };
 	u64 margin_ns = (u64)(ioc->period_us *
 			      WAITQ_TIMER_MARGIN_PCT / 100) * NSEC_PER_USEC;
-	u64 abs_vdebt, vdebt, vshortage, expires, oexpires;
+	u64 vdebt, vshortage, expires, oexpires;
 	s64 vbudget;
 	u32 hw_inuse;
 
@@ -1153,18 +1153,15 @@ static void iocg_kick_waitq(struct ioc_gq *iocg, struct ioc_now *now)
 	vbudget = now->vnow - atomic64_read(&iocg->vtime);
 
 	/* pay off debt */
-	abs_vdebt = atomic64_read(&iocg->abs_vdebt);
-	vdebt = abs_cost_to_cost(abs_vdebt, hw_inuse);
+	vdebt = abs_cost_to_cost(iocg->abs_vdebt, hw_inuse);
 	if (vdebt && vbudget > 0) {
 		u64 delta = min_t(u64, vbudget, vdebt);
 		u64 abs_delta = min(cost_to_abs_cost(delta, hw_inuse),
-				    abs_vdebt);
+				    iocg->abs_vdebt);
 
 		atomic64_add(delta, &iocg->vtime);
 		atomic64_add(delta, &iocg->done_vtime);
-		atomic64_sub(abs_delta, &iocg->abs_vdebt);
-		if (WARN_ON_ONCE(atomic64_read(&iocg->abs_vdebt) < 0))
-			atomic64_set(&iocg->abs_vdebt, 0);
+		iocg->abs_vdebt -= abs_delta;
 	}
 
 	/*
@@ -1220,12 +1217,18 @@ static bool iocg_kick_delay(struct ioc_gq *iocg, struct ioc_now *now)
 	u64 delta_ns, expires, oexpires;
 	u32 hw_inuse;
 
+	lockdep_assert_held(&iocg->waitq.lock);
+
 	/* debt-adjust vtime */
 	current_hweight(iocg, NULL, &hw_inuse);
-	vtime += abs_cost_to_cost(atomic64_read(&iocg->abs_vdebt), hw_inuse);
+	vtime += abs_cost_to_cost(iocg->abs_vdebt, hw_inuse);
 
-	/* clear or maintain depending on the overage */
-	if (time_before_eq64(vtime, now->vnow)) {
+	/*
+	 * Clear or maintain depending on the overage. Non-zero vdebt is what
+	 * guarantees that @iocg is online and future iocg_kick_delay() will
+	 * clear use_delay. Don't leave it on when there's no vdebt.
+	 */
+	if (!iocg->abs_vdebt || time_before_eq64(vtime, now->vnow)) {
 		blkcg_clear_delay(blkg);
 		return false;
 	}
@@ -1254,9 +1257,12 @@ static enum hrtimer_restart iocg_delay_timer_fn(struct hrtimer *timer)
 {
 	struct ioc_gq *iocg = container_of(timer, struct ioc_gq, delay_timer);
 	struct ioc_now now;
+	unsigned long flags;
 
+	spin_lock_irqsave(&iocg->waitq.lock, flags);
 	ioc_now(iocg->ioc, &now);
 	iocg_kick_delay(iocg, &now);
+	spin_unlock_irqrestore(&iocg->waitq.lock, flags);
 
 	return HRTIMER_NORESTART;
 }
@@ -1364,14 +1370,13 @@ static void ioc_timer_fn(struct timer_list *timer)
 	 * should have woken up in the last period and expire idle iocgs.
 	 */
 	list_for_each_entry_safe(iocg, tiocg, &ioc->active_iocgs, active_list) {
-		if (!waitqueue_active(&iocg->waitq) &&
-		    !atomic64_read(&iocg->abs_vdebt) && !iocg_is_idle(iocg))
+		if (!waitqueue_active(&iocg->waitq) && iocg->abs_vdebt &&
+		    !iocg_is_idle(iocg))
 			continue;
 
 		spin_lock(&iocg->waitq.lock);
 
-		if (waitqueue_active(&iocg->waitq) ||
-		    atomic64_read(&iocg->abs_vdebt)) {
+		if (waitqueue_active(&iocg->waitq) || iocg->abs_vdebt) {
 			/* might be oversleeping vtime / hweight changes, kick */
 			iocg_kick_waitq(iocg, &now);
 			iocg_kick_delay(iocg, &now);
@@ -1587,7 +1592,7 @@ static void ioc_timer_fn(struct timer_list *timer)
 				      vrate_min, vrate_max);
 		}
 
-		trace_iocost_ioc_vrate_adj(ioc, vrate, &missed_ppm, rq_wait_pct,
+		trace_iocost_ioc_vrate_adj(ioc, vrate, missed_ppm, rq_wait_pct,
 					   nr_lagging, nr_shortages,
 					   nr_surpluses);
 
@@ -1596,7 +1601,7 @@ static void ioc_timer_fn(struct timer_list *timer)
 			ioc->period_us * vrate * INUSE_MARGIN_PCT, 100);
 	} else if (ioc->busy_level != prev_busy_level || nr_lagging) {
 		trace_iocost_ioc_vrate_adj(ioc, atomic64_read(&ioc->vtime_rate),
-					   &missed_ppm, rq_wait_pct, nr_lagging,
+					   missed_ppm, rq_wait_pct, nr_lagging,
 					   nr_shortages, nr_surpluses);
 	}
 
@@ -1739,28 +1744,49 @@ static void ioc_rqos_throttle(struct rq_qos *rqos, struct bio *bio)
 	 * tests are racy but the races aren't systemic - we only miss once
 	 * in a while which is fine.
 	 */
-	if (!waitqueue_active(&iocg->waitq) &&
-	    !atomic64_read(&iocg->abs_vdebt) &&
+	if (!waitqueue_active(&iocg->waitq) && !iocg->abs_vdebt &&
 	    time_before_eq64(vtime + cost, now.vnow)) {
 		iocg_commit_bio(iocg, bio, cost);
 		return;
 	}
 
 	/*
-	 * We're over budget.  If @bio has to be issued regardless,
-	 * remember the abs_cost instead of advancing vtime.
-	 * iocg_kick_waitq() will pay off the debt before waking more IOs.
+	 * We activated above but w/o any synchronization. Deactivation is
+	 * synchronized with waitq.lock and we won't get deactivated as long
+	 * as we're waiting or has debt, so we're good if we're activated
+	 * here. In the unlikely case that we aren't, just issue the IO.
+	 */
+	spin_lock_irq(&iocg->waitq.lock);
+
+	if (unlikely(list_empty(&iocg->active_list))) {
+		spin_unlock_irq(&iocg->waitq.lock);
+		iocg_commit_bio(iocg, bio, cost);
+		return;
+	}
+
+	/*
+	 * We're over budget. If @bio has to be issued regardless, remember
+	 * the abs_cost instead of advancing vtime. iocg_kick_waitq() will pay
+	 * off the debt before waking more IOs.
+	 *
 	 * This way, the debt is continuously paid off each period with the
-	 * actual budget available to the cgroup.  If we just wound vtime,
-	 * we would incorrectly use the current hw_inuse for the entire
-	 * amount which, for example, can lead to the cgroup staying
-	 * blocked for a long time even with substantially raised hw_inuse.
+	 * actual budget available to the cgroup. If we just wound vtime, we
+	 * would incorrectly use the current hw_inuse for the entire amount
+	 * which, for example, can lead to the cgroup staying blocked for a
+	 * long time even with substantially raised hw_inuse.
+	 *
+	 * An iocg with vdebt should stay online so that the timer can keep
+	 * deducting its vdebt and [de]activate use_delay mechanism
+	 * accordingly. We don't want to race against the timer trying to
+	 * clear them and leave @iocg inactive w/ dangling use_delay heavily
+	 * penalizing the cgroup and its descendants.
 	 */
 	if (bio_issue_as_root_blkg(bio) || fatal_signal_pending(current)) {
-		atomic64_add(abs_cost, &iocg->abs_vdebt);
+		iocg->abs_vdebt += abs_cost;
 		if (iocg_kick_delay(iocg, &now))
 			blkcg_schedule_throttle(rqos->q,
 					(bio->bi_opf & REQ_SWAP) == REQ_SWAP);
+		spin_unlock_irq(&iocg->waitq.lock);
 		return;
 	}
 
@@ -1777,20 +1803,6 @@ static void ioc_rqos_throttle(struct rq_qos *rqos, struct bio *bio)
 	 * All waiters are on iocg->waitq and the wait states are
 	 * synchronized using waitq.lock.
 	 */
-	spin_lock_irq(&iocg->waitq.lock);
-
-	/*
-	 * We activated above but w/o any synchronization.  Deactivation is
-	 * synchronized with waitq.lock and we won't get deactivated as
-	 * long as we're waiting, so we're good if we're activated here.
-	 * In the unlikely case that we are deactivated, just issue the IO.
-	 */
-	if (unlikely(list_empty(&iocg->active_list))) {
-		spin_unlock_irq(&iocg->waitq.lock);
-		iocg_commit_bio(iocg, bio, cost);
-		return;
-	}
-
 	init_waitqueue_func_entry(&wait.wait, iocg_wake_fn);
 	wait.wait.private = current;
 	wait.bio = bio;
@@ -1822,6 +1834,7 @@ static void ioc_rqos_merge(struct rq_qos *rqos, struct request *rq,
 	struct ioc_now now;
 	u32 hw_inuse;
 	u64 abs_cost, cost;
+	unsigned long flags;
 
 	/* bypass if disabled or for root cgroup */
 	if (!ioc->enabled || !iocg->level)
@@ -1841,15 +1854,28 @@ static void ioc_rqos_merge(struct rq_qos *rqos, struct request *rq,
 		iocg->cursor = bio_end;
 
 	/*
-	 * Charge if there's enough vtime budget and the existing request
-	 * has cost assigned.  Otherwise, account it as debt.  See debt
-	 * handling in ioc_rqos_throttle() for details.
+	 * Charge if there's enough vtime budget and the existing request has
+	 * cost assigned.
 	 */
 	if (rq->bio && rq->bio->bi_iocost_cost &&
-	    time_before_eq64(atomic64_read(&iocg->vtime) + cost, now.vnow))
+	    time_before_eq64(atomic64_read(&iocg->vtime) + cost, now.vnow)) {
 		iocg_commit_bio(iocg, bio, cost);
-	else
-		atomic64_add(abs_cost, &iocg->abs_vdebt);
+		return;
+	}
+
+	/*
+	 * Otherwise, account it as debt if @iocg is online, which it should
+	 * be for the vast majority of cases. See debt handling in
+	 * ioc_rqos_throttle() for details.
+	 */
+	spin_lock_irqsave(&iocg->waitq.lock, flags);
+	if (likely(!list_empty(&iocg->active_list))) {
+		iocg->abs_vdebt += abs_cost;
+		iocg_kick_delay(iocg, &now);
+	} else {
+		iocg_commit_bio(iocg, bio, cost);
+	}
+	spin_unlock_irqrestore(&iocg->waitq.lock, flags);
 }
 
 static void ioc_rqos_done_bio(struct rq_qos *rqos, struct bio *bio)
@@ -2021,7 +2047,6 @@ static void ioc_pd_init(struct blkg_policy_data *pd)
 	iocg->ioc = ioc;
 	atomic64_set(&iocg->vtime, now.vnow);
 	atomic64_set(&iocg->done_vtime, now.vnow);
-	atomic64_set(&iocg->abs_vdebt, 0);
 	atomic64_set(&iocg->active_period, atomic64_read(&ioc->cur_period));
 	INIT_LIST_HEAD(&iocg->active_list);
 	iocg->hweight_active = HWEIGHT_WHOLE;

block/partitions/core.c

@@ -610,7 +610,7 @@ int blk_drop_partitions(struct block_device *bdev)
 
 	if (!disk_part_scan_enabled(bdev->bd_disk))
 		return 0;
-	if (bdev->bd_part_count || bdev->bd_openers > 1)
+	if (bdev->bd_part_count)
 		return -EBUSY;
 
 	sync_blockdev(bdev);

drivers/block/null_blk.h

@@ -85,26 +85,35 @@ struct nullb {
 	char disk_name[DISK_NAME_LEN];
 };
 
+blk_status_t null_process_cmd(struct nullb_cmd *cmd,
+			      enum req_opf op, sector_t sector,
+			      unsigned int nr_sectors);
+
 #ifdef CONFIG_BLK_DEV_ZONED
-int null_zone_init(struct nullb_device *dev);
-void null_zone_exit(struct nullb_device *dev);
+int null_init_zoned_dev(struct nullb_device *dev, struct request_queue *q);
+int null_register_zoned_dev(struct nullb *nullb);
+void null_free_zoned_dev(struct nullb_device *dev);
 int null_report_zones(struct gendisk *disk, sector_t sector,
 		      unsigned int nr_zones, report_zones_cb cb, void *data);
-blk_status_t null_handle_zoned(struct nullb_cmd *cmd,
-				enum req_opf op, sector_t sector,
-				sector_t nr_sectors);
+blk_status_t null_process_zoned_cmd(struct nullb_cmd *cmd,
+				    enum req_opf op, sector_t sector,
+				    sector_t nr_sectors);
 size_t null_zone_valid_read_len(struct nullb *nullb,
 				sector_t sector, unsigned int len);
 #else
-static inline int null_zone_init(struct nullb_device *dev)
+static inline int null_init_zoned_dev(struct nullb_device *dev,
+				      struct request_queue *q)
 {
 	pr_err("CONFIG_BLK_DEV_ZONED not enabled\n");
 	return -EINVAL;
 }
-static inline void null_zone_exit(struct nullb_device *dev) {}
-static inline blk_status_t null_handle_zoned(struct nullb_cmd *cmd,
-					     enum req_opf op, sector_t sector,
-					     sector_t nr_sectors)
+static inline int null_register_zoned_dev(struct nullb *nullb)
+{
+	return -ENODEV;
+}
+static inline void null_free_zoned_dev(struct nullb_device *dev) {}
+static inline blk_status_t null_process_zoned_cmd(struct nullb_cmd *cmd,
+			enum req_opf op, sector_t sector, sector_t nr_sectors)
 {
 	return BLK_STS_NOTSUPP;
 }

drivers/block/null_blk_main.c

@@ -580,7 +580,7 @@ static void null_free_dev(struct nullb_device *dev)
 	if (!dev)
 		return;
 
-	null_zone_exit(dev);
+	null_free_zoned_dev(dev);
 	badblocks_exit(&dev->badblocks);
 	kfree(dev);
 }
@@ -1276,6 +1276,25 @@ static inline void nullb_complete_cmd(struct nullb_cmd *cmd)
 	}
 }
 
+blk_status_t null_process_cmd(struct nullb_cmd *cmd,
+			      enum req_opf op, sector_t sector,
+			      unsigned int nr_sectors)
+{
+	struct nullb_device *dev = cmd->nq->dev;
+	blk_status_t ret;
+
+	if (dev->badblocks.shift != -1) {
+		ret = null_handle_badblocks(cmd, sector, nr_sectors);
+		if (ret != BLK_STS_OK)
+			return ret;
+	}
+
+	if (dev->memory_backed)
+		return null_handle_memory_backed(cmd, op);
+
+	return BLK_STS_OK;
+}
+
 static blk_status_t null_handle_cmd(struct nullb_cmd *cmd, sector_t sector,
 				    sector_t nr_sectors, enum req_opf op)
 {
@@ -1294,17 +1313,11 @@ static blk_status_t null_handle_cmd(struct nullb_cmd *cmd, sector_t sector,
 		goto out;
 	}
 
-	if (nullb->dev->badblocks.shift != -1) {
-		cmd->error = null_handle_badblocks(cmd, sector, nr_sectors);
-		if (cmd->error != BLK_STS_OK)
-			goto out;
-	}
-
-	if (dev->memory_backed)
-		cmd->error = null_handle_memory_backed(cmd, op);
-
-	if (!cmd->error && dev->zoned)
-		cmd->error = null_handle_zoned(cmd, op, sector, nr_sectors);
+	if (dev->zoned)
+		cmd->error = null_process_zoned_cmd(cmd, op,
+						    sector, nr_sectors);
+	else
+		cmd->error = null_process_cmd(cmd, op, sector, nr_sectors);
 
 out:
 	nullb_complete_cmd(cmd);
@@ -1605,19 +1618,12 @@ static int null_gendisk_register(struct nullb *nullb)
 	disk->queue		= nullb->q;
 	strncpy(disk->disk_name, nullb->disk_name, DISK_NAME_LEN);
 
-#ifdef CONFIG_BLK_DEV_ZONED
 	if (nullb->dev->zoned) {
-		if (queue_is_mq(nullb->q)) {
-			int ret = blk_revalidate_disk_zones(disk);
-			if (ret)
-				return ret;
-		} else {
-			blk_queue_chunk_sectors(nullb->q,
-					nullb->dev->zone_size_sects);
-			nullb->q->nr_zones = blkdev_nr_zones(disk);
-		}
+		int ret = null_register_zoned_dev(nullb);
+
+		if (ret)
+			return ret;
 	}
-#endif
 
 	add_disk(disk);
 	return 0;
@@ -1773,14 +1779,9 @@ static int null_add_dev(struct nullb_device *dev)
 	}
 
 	if (dev->zoned) {
-		rv = null_zone_init(dev);
+		rv = null_init_zoned_dev(dev, nullb->q);
 		if (rv)
 			goto out_cleanup_blk_queue;
-
-		nullb->q->limits.zoned = BLK_ZONED_HM;
-		blk_queue_flag_set(QUEUE_FLAG_ZONE_RESETALL, nullb->q);
-		blk_queue_required_elevator_features(nullb->q,
-						ELEVATOR_F_ZBD_SEQ_WRITE);
 	}
 
 	nullb->q->queuedata = nullb;
@@ -1809,8 +1810,7 @@ static int null_add_dev(struct nullb_device *dev)
 
 	return 0;
 out_cleanup_zone:
-	if (dev->zoned)
-		null_zone_exit(dev);
+	null_free_zoned_dev(dev);
 out_cleanup_blk_queue:
 	blk_cleanup_queue(nullb->q);
 out_cleanup_tags:

drivers/block/null_blk_zoned.c

@@ -13,7 +13,7 @@ static inline unsigned int null_zone_no(struct nullb_device *dev, sector_t sect)
 	return sect >> ilog2(dev->zone_size_sects);
 }
 
-int null_zone_init(struct nullb_device *dev)
+int null_init_zoned_dev(struct nullb_device *dev, struct request_queue *q)
 {
 	sector_t dev_size = (sector_t)dev->size * 1024 * 1024;
 	sector_t sector = 0;
@@ -61,10 +61,27 @@ int null_zone_init(struct nullb_device *dev)
 		sector += dev->zone_size_sects;
 	}
 
+	q->limits.zoned = BLK_ZONED_HM;
+	blk_queue_flag_set(QUEUE_FLAG_ZONE_RESETALL, q);
+	blk_queue_required_elevator_features(q, ELEVATOR_F_ZBD_SEQ_WRITE);
+
+	return 0;
+}
+
+int null_register_zoned_dev(struct nullb *nullb)
+{
+	struct request_queue *q = nullb->q;
+
+	if (queue_is_mq(q))
+		return blk_revalidate_disk_zones(nullb->disk);
+
+	blk_queue_chunk_sectors(q, nullb->dev->zone_size_sects);
+	q->nr_zones = blkdev_nr_zones(nullb->disk);
+
 	return 0;
 }
 
-void null_zone_exit(struct nullb_device *dev)
+void null_free_zoned_dev(struct nullb_device *dev)
 {
 	kvfree(dev->zones);
 }
@@ -126,11 +143,16 @@ static blk_status_t null_zone_write(struct nullb_cmd *cmd, sector_t sector,
 	struct nullb_device *dev = cmd->nq->dev;
 	unsigned int zno = null_zone_no(dev, sector);
 	struct blk_zone *zone = &dev->zones[zno];
+	blk_status_t ret;
+
+	trace_nullb_zone_op(cmd, zno, zone->cond);
+
+	if (zone->type == BLK_ZONE_TYPE_CONVENTIONAL)
+		return null_process_cmd(cmd, REQ_OP_WRITE, sector, nr_sectors);
 
 	switch (zone->cond) {
 	case BLK_ZONE_COND_FULL:
 		/* Cannot write to a full zone */
-		cmd->error = BLK_STS_IOERR;
 		return BLK_STS_IOERR;
 	case BLK_ZONE_COND_EMPTY:
 	case BLK_ZONE_COND_IMP_OPEN:
@@ -143,19 +165,18 @@ static blk_status_t null_zone_write(struct nullb_cmd *cmd, sector_t sector,
 		if (zone->cond != BLK_ZONE_COND_EXP_OPEN)
 			zone->cond = BLK_ZONE_COND_IMP_OPEN;
 
+		ret = null_process_cmd(cmd, REQ_OP_WRITE, sector, nr_sectors);
+		if (ret != BLK_STS_OK)
+			return ret;
+
 		zone->wp += nr_sectors;
 		if (zone->wp == zone->start + zone->len)
 			zone->cond = BLK_ZONE_COND_FULL;
-		break;
-	case BLK_ZONE_COND_NOT_WP:
-		break;
+		return BLK_STS_OK;
 	default:
 		/* Invalid zone condition */
 		return BLK_STS_IOERR;
 	}
-
-	trace_nullb_zone_op(cmd, zno, zone->cond);
-	return BLK_STS_OK;
 }
 
 static blk_status_t null_zone_mgmt(struct nullb_cmd *cmd, enum req_opf op,
@@ -216,8 +237,8 @@ static blk_status_t null_zone_mgmt(struct nullb_cmd *cmd, enum req_opf op,
 	return BLK_STS_OK;
 }
 
-blk_status_t null_handle_zoned(struct nullb_cmd *cmd, enum req_opf op,
-			       sector_t sector, sector_t nr_sectors)
+blk_status_t null_process_zoned_cmd(struct nullb_cmd *cmd, enum req_opf op,
+				    sector_t sector, sector_t nr_sectors)
 {
 	switch (op) {
 	case REQ_OP_WRITE:
@@ -229,6 +250,6 @@ blk_status_t null_handle_zoned(struct nullb_cmd *cmd, enum req_opf op,
 	case REQ_OP_ZONE_FINISH:
 		return null_zone_mgmt(cmd, op, sector);
 	default:
-		return BLK_STS_OK;
+		return null_process_cmd(cmd, op, sector, nr_sectors);
 	}
 }

drivers/nvme/host/core.c

@@ -1110,7 +1110,7 @@ static int nvme_identify_ns_descs(struct nvme_ctrl *ctrl, unsigned nsid,
 		  * Don't treat an error as fatal, as we potentially already
 		  * have a NGUID or EUI-64.
 		  */
-		if (status > 0)
+		if (status > 0 && !(status & NVME_SC_DNR))
 			status = 0;
 		goto free_data;
 	}
@@ -3642,6 +3642,8 @@ static void nvme_alloc_ns(struct nvme_ctrl *ctrl, unsigned nsid)
 
 	return;
  out_put_disk:
+	/* prevent double queue cleanup */
+	ns->disk->queue = NULL;
 	put_disk(ns->disk);
  out_unlink_ns:
 	mutex_lock(&ctrl->subsys->lock);

drivers/nvme/host/pci.c

@@ -973,9 +973,13 @@ static inline void nvme_handle_cqe(struct nvme_queue *nvmeq, u16 idx)
 
 static inline void nvme_update_cq_head(struct nvme_queue *nvmeq)
 {
-	if (++nvmeq->cq_head == nvmeq->q_depth) {
+	u16 tmp = nvmeq->cq_head + 1;
+
+	if (tmp == nvmeq->q_depth) {
 		nvmeq->cq_head = 0;
 		nvmeq->cq_phase ^= 1;
+	} else {
+		nvmeq->cq_head = tmp;
 	}
 }
 

fs/block_dev.c

@@ -19,7 +19,6 @@
 #include <linux/module.h>
 #include <linux/blkpg.h>
 #include <linux/magic.h>
-#include <linux/dax.h>
 #include <linux/buffer_head.h>
 #include <linux/swap.h>
 #include <linux/pagevec.h>
@@ -1876,6 +1875,16 @@ static void __blkdev_put(struct block_device *bdev, fmode_t mode, int for_part)
 	struct gendisk *disk = bdev->bd_disk;
 	struct block_device *victim = NULL;
 
+	/*
+	 * Sync early if it looks like we're the last one.  If someone else
+	 * opens the block device between now and the decrement of bd_openers
+	 * then we did a sync that we didn't need to, but that's not the end
+	 * of the world and we want to avoid long (could be several minute)
+	 * syncs while holding the mutex.
+	 */
+	if (bdev->bd_openers == 1)
+		sync_blockdev(bdev);
+
 	mutex_lock_nested(&bdev->bd_mutex, for_part);
 	if (for_part)
 		bdev->bd_part_count--;

fs/buffer.c

@@ -967,7 +967,7 @@ grow_dev_page(struct block_device *bdev, sector_t block,
 	struct page *page;
 	struct buffer_head *bh;
 	sector_t end_block;
-	int ret = 0;		/* Will call free_more_memory() */
+	int ret = 0;
 	gfp_t gfp_mask;
 
 	gfp_mask = mapping_gfp_constraint(inode->i_mapping, ~__GFP_FS) | gfp;

fs/ceph/debugfs.c

@@ -271,7 +271,7 @@ void ceph_fs_debugfs_init(struct ceph_fs_client *fsc)
 				    &congestion_kb_fops);
 
 	snprintf(name, sizeof(name), "../../bdi/%s",
-		 dev_name(fsc->sb->s_bdi->dev));
+		 bdi_dev_name(fsc->sb->s_bdi));
 	fsc->debugfs_bdi =
 		debugfs_create_symlink("bdi",
 				       fsc->client->debugfs_dir,

fs/vboxsf/super.c

@@ -164,7 +164,7 @@ static int vboxsf_fill_super(struct super_block *sb, struct fs_context *fc)
 		goto fail_free;
 	}
 
-	err = super_setup_bdi_name(sb, "vboxsf-%s.%d", fc->source, sbi->bdi_id);
+	err = super_setup_bdi_name(sb, "vboxsf-%d", sbi->bdi_id);
 	if (err)
 		goto fail_free;
 

include/linux/backing-dev-defs.h

@@ -54,7 +54,6 @@ enum wb_reason {
 	WB_REASON_SYNC,
 	WB_REASON_PERIODIC,
 	WB_REASON_LAPTOP_TIMER,
-	WB_REASON_FREE_MORE_MEM,
 	WB_REASON_FS_FREE_SPACE,
 	/*
 	 * There is no bdi forker thread any more and works are done
@@ -220,6 +219,7 @@ struct backing_dev_info {
 	wait_queue_head_t wb_waitq;
 
 	struct device *dev;
+	char dev_name[64];
 	struct device *owner;
 
 	struct timer_list laptop_mode_wb_timer;

include/linux/backing-dev.h

@@ -505,13 +505,6 @@ static inline int bdi_rw_congested(struct backing_dev_info *bdi)
 				  (1 << WB_async_congested));
 }
 
-extern const char *bdi_unknown_name;
-
-static inline const char *bdi_dev_name(struct backing_dev_info *bdi)
-{
-	if (!bdi || !bdi->dev)
-		return bdi_unknown_name;
-	return dev_name(bdi->dev);
-}
+const char *bdi_dev_name(struct backing_dev_info *bdi);
 
 #endif	/* _LINUX_BACKING_DEV_H */

include/trace/events/iocost.h

@@ -130,7 +130,7 @@ DEFINE_EVENT(iocg_inuse_update, iocost_inuse_reset,
 
 TRACE_EVENT(iocost_ioc_vrate_adj,
 
-	TP_PROTO(struct ioc *ioc, u64 new_vrate, u32 (*missed_ppm)[2],
+	TP_PROTO(struct ioc *ioc, u64 new_vrate, u32 *missed_ppm,
 		u32 rq_wait_pct, int nr_lagging, int nr_shortages,
 		int nr_surpluses),
 
@@ -155,8 +155,8 @@ TRACE_EVENT(iocost_ioc_vrate_adj,
 		__entry->old_vrate = atomic64_read(&ioc->vtime_rate);;
 		__entry->new_vrate = new_vrate;
 		__entry->busy_level = ioc->busy_level;
-		__entry->read_missed_ppm = (*missed_ppm)[READ];
-		__entry->write_missed_ppm = (*missed_ppm)[WRITE];
+		__entry->read_missed_ppm = missed_ppm[READ];
+		__entry->write_missed_ppm = missed_ppm[WRITE];
 		__entry->rq_wait_pct = rq_wait_pct;
 		__entry->nr_lagging = nr_lagging;
 		__entry->nr_shortages = nr_shortages;

include/trace/events/wbt.h

@@ -33,7 +33,7 @@ TRACE_EVENT(wbt_stat,
 	),
 
 	TP_fast_assign(
-		strlcpy(__entry->name, dev_name(bdi->dev),
+		strlcpy(__entry->name, bdi_dev_name(bdi),
 			ARRAY_SIZE(__entry->name));
 		__entry->rmean		= stat[0].mean;
 		__entry->rmin		= stat[0].min;
@@ -68,7 +68,7 @@ TRACE_EVENT(wbt_lat,
 	),
 
 	TP_fast_assign(
-		strlcpy(__entry->name, dev_name(bdi->dev),
+		strlcpy(__entry->name, bdi_dev_name(bdi),
 			ARRAY_SIZE(__entry->name));
 		__entry->lat = div_u64(lat, 1000);
 	),
@@ -105,7 +105,7 @@ TRACE_EVENT(wbt_step,
 	),
 
 	TP_fast_assign(
-		strlcpy(__entry->name, dev_name(bdi->dev),
+		strlcpy(__entry->name, bdi_dev_name(bdi),
 			ARRAY_SIZE(__entry->name));
 		__entry->msg	= msg;
 		__entry->step	= step;
@@ -141,7 +141,7 @@ TRACE_EVENT(wbt_timer,
 	),
 
 	TP_fast_assign(
-		strlcpy(__entry->name, dev_name(bdi->dev),
+		strlcpy(__entry->name, bdi_dev_name(bdi),
 			ARRAY_SIZE(__entry->name));
 		__entry->status		= status;
 		__entry->step		= step;

include/trace/events/writeback.h

@@ -36,7 +36,6 @@
 	EM( WB_REASON_SYNC,			"sync")			\
 	EM( WB_REASON_PERIODIC,			"periodic")		\
 	EM( WB_REASON_LAPTOP_TIMER,		"laptop_timer")		\
-	EM( WB_REASON_FREE_MORE_MEM,		"free_more_memory")	\
 	EM( WB_REASON_FS_FREE_SPACE,		"fs_free_space")	\
 	EMe(WB_REASON_FORKER_THREAD,		"forker_thread")
 

mm/backing-dev.c

@@ -21,7 +21,7 @@ struct backing_dev_info noop_backing_dev_info = {
 EXPORT_SYMBOL_GPL(noop_backing_dev_info);
 
 static struct class *bdi_class;
-const char *bdi_unknown_name = "(unknown)";
+static const char *bdi_unknown_name = "(unknown)";
 
 /*
  * bdi_lock protects bdi_tree and updates to bdi_list. bdi_list has RCU
@@ -938,7 +938,8 @@ int bdi_register_va(struct backing_dev_info *bdi, const char *fmt, va_list args)
 	if (bdi->dev)	/* The driver needs to use separate queues per device */
 		return 0;
 
-	dev = device_create_vargs(bdi_class, NULL, MKDEV(0, 0), bdi, fmt, args);
+	vsnprintf(bdi->dev_name, sizeof(bdi->dev_name), fmt, args);
+	dev = device_create(bdi_class, NULL, MKDEV(0, 0), bdi, bdi->dev_name);
 	if (IS_ERR(dev))
 		return PTR_ERR(dev);
 
@@ -1043,6 +1044,14 @@ void bdi_put(struct backing_dev_info *bdi)
 }
 EXPORT_SYMBOL(bdi_put);
 
+const char *bdi_dev_name(struct backing_dev_info *bdi)
+{
+	if (!bdi || !bdi->dev)
+		return bdi_unknown_name;
+	return bdi->dev_name;
+}
+EXPORT_SYMBOL_GPL(bdi_dev_name);
+
 static wait_queue_head_t congestion_wqh[2] = {
 		__WAIT_QUEUE_HEAD_INITIALIZER(congestion_wqh[0]),
 		__WAIT_QUEUE_HEAD_INITIALIZER(congestion_wqh[1])

tools/cgroup/iocost_monitor.py

@@ -160,7 +160,12 @@ class IocgStat:
         else:
             self.inflight_pct = 0
 
-        self.debt_ms = iocg.abs_vdebt.counter.value_() / VTIME_PER_USEC / 1000
+        # vdebt used to be an atomic64_t and is now u64, support both
+        try:
+            self.debt_ms = iocg.abs_vdebt.counter.value_() / VTIME_PER_USEC / 1000
+        except:
+            self.debt_ms = iocg.abs_vdebt.value_() / VTIME_PER_USEC / 1000
+
         self.use_delay = blkg.use_delay.counter.value_()
         self.delay_ms = blkg.delay_nsec.counter.value_() / 1_000_000