Merge tag 'for-linus-20180425' of git://git.kernel.dk/linux-block

Pull block updates from Jens Axboe:
 "I ended up sitting on this about a week longer than I wanted to, since
  we were hashing out details with a timeout change. I've now killed
  that patch, so we can flush the existing queue in due time.

  This contains:

   - Fix for an old regression, where entering the queue can be
     disturbed by a signal to the process. This can cause spurious EIO.
     Fix from Alan Jenkins.

   - cdrom information leak fix from Dan.

   - Trivial helper for testing queue FUA from Dave Chinner, part of his
     O_DIRECT FUA series.

   - Series of swim fixes from Finn that actually makes it work again.

   - Loop O_DIRECT corruption fix, which caused data corruption in
     production for us. From me.

   - BFQ crash fix from me.

   - bcache maintainer update. Michael no longer has the time to do it,
     Coly has stepped up to serve as the new maintainer.

   - blkcg locking fixes from Jiang Biao.

   - Revert of a change from this merge window from Ming, that causes an
     issue on some hardware.

   - Minor clarification doc addition from Linus Walleij"

* tag 'for-linus-20180425' of git://git.kernel.dk/linux-block: (22 commits)
  Revert "blk-mq: remove code for dealing with remapping queue"
  block: mq: Add some minor doc for core structs
  bcache: mark Coly Li as bcache maintainer
  MAINTAINERS: Remove me as maintainer of bcache
  blkcg: init root blkcg_gq under lock
  blkcg: small fix on comment in blkcg_init_queue
  blkcg: don't hold blkcg lock when deactivating policy
  block: add blk_queue_fua() helper function
  cdrom: information leak in cdrom_ioctl_media_changed()
  bfq-iosched: ensure to clear bic/bfqq pointers when preparing request
  blk-mq: start request gstate with gen 1
  block/swim: Select appropriate drive on device open
  block/swim: Fix IO error at end of medium
  block/swim: Check drive type
  block/swim: Rename macros to avoid inconsistent inverted logic
  block/swim: Don't log an error message for an invalid ioctl
  block/swim: Remove extra put_disk() call from error path
  block/swim: Fix array bounds check
  m68k/mac: Don't remap SWIM MMIO region
  loop: handle short DIO reads
  ...

MAINTAINERS

@@ -2617,7 +2617,7 @@ S:	Maintained
 F:	drivers/net/hamradio/baycom*
 
 BCACHE (BLOCK LAYER CACHE)
-M:	Michael Lyle <mlyle@lyle.org>
+M:	Coly Li <colyli@suse.de>
 M:	Kent Overstreet <kent.overstreet@gmail.com>
 L:	linux-bcache@vger.kernel.org
 W:	http://bcache.evilpiepirate.org

block/bfq-iosched.c

@@ -4934,8 +4934,16 @@ static void bfq_prepare_request(struct request *rq, struct bio *bio)
 	bool new_queue = false;
 	bool bfqq_already_existing = false, split = false;
 
-	if (!rq->elv.icq)
+	/*
+	 * Even if we don't have an icq attached, we should still clear
+	 * the scheduler pointers, as they might point to previously
+	 * allocated bic/bfqq structs.
+	 */
+	if (!rq->elv.icq) {
+		rq->elv.priv[0] = rq->elv.priv[1] = NULL;
 		return;
+	}
+
 	bic = icq_to_bic(rq->elv.icq);
 
 	spin_lock_irq(&bfqd->lock);

block/blk-cgroup.c

@@ -1177,26 +1177,20 @@ int blkcg_init_queue(struct request_queue *q)
 
 	preloaded = !radix_tree_preload(GFP_KERNEL);
 
-	/*
-	 * Make sure the root blkg exists and count the existing blkgs.  As
-	 * @q is bypassing at this point, blkg_lookup_create() can't be
-	 * used.  Open code insertion.
-	 */
+	/* Make sure the root blkg exists. */
 	rcu_read_lock();
 	spin_lock_irq(q->queue_lock);
 	blkg = blkg_create(&blkcg_root, q, new_blkg);
+	if (IS_ERR(blkg))
+		goto err_unlock;
+	q->root_blkg = blkg;
+	q->root_rl.blkg = blkg;
 	spin_unlock_irq(q->queue_lock);
 	rcu_read_unlock();
 
 	if (preloaded)
 		radix_tree_preload_end();
 
-	if (IS_ERR(blkg))
-		return PTR_ERR(blkg);
-
-	q->root_blkg = blkg;
-	q->root_rl.blkg = blkg;
-
 	ret = blk_throtl_init(q);
 	if (ret) {
 		spin_lock_irq(q->queue_lock);
@@ -1204,6 +1198,13 @@ int blkcg_init_queue(struct request_queue *q)
 		spin_unlock_irq(q->queue_lock);
 	}
 	return ret;
+
+err_unlock:
+	spin_unlock_irq(q->queue_lock);
+	rcu_read_unlock();
+	if (preloaded)
+		radix_tree_preload_end();
+	return PTR_ERR(blkg);
 }
 
 /**
@@ -1410,9 +1411,6 @@ void blkcg_deactivate_policy(struct request_queue *q,
 	__clear_bit(pol->plid, q->blkcg_pols);
 
 	list_for_each_entry(blkg, &q->blkg_list, q_node) {
-		/* grab blkcg lock too while removing @pd from @blkg */
-		spin_lock(&blkg->blkcg->lock);
-
 		if (blkg->pd[pol->plid]) {
 			if (!blkg->pd[pol->plid]->offline &&
 			    pol->pd_offline_fn) {
@@ -1422,8 +1420,6 @@ void blkcg_deactivate_policy(struct request_queue *q,
 			pol->pd_free_fn(blkg->pd[pol->plid]);
 			blkg->pd[pol->plid] = NULL;
 		}
-
-		spin_unlock(&blkg->blkcg->lock);
 	}
 
 	spin_unlock_irq(q->queue_lock);

block/blk-core.c

@@ -201,6 +201,10 @@ void blk_rq_init(struct request_queue *q, struct request *rq)
 	rq->part = NULL;
 	seqcount_init(&rq->gstate_seq);
 	u64_stats_init(&rq->aborted_gstate_sync);
+	/*
+	 * See comment of blk_mq_init_request
+	 */
+	WRITE_ONCE(rq->gstate, MQ_RQ_GEN_INC);
 }
 EXPORT_SYMBOL(blk_rq_init);
 
@@ -915,7 +919,6 @@ int blk_queue_enter(struct request_queue *q, blk_mq_req_flags_t flags)
 
 	while (true) {
 		bool success = false;
-		int ret;
 
 		rcu_read_lock();
 		if (percpu_ref_tryget_live(&q->q_usage_counter)) {
@@ -947,14 +950,12 @@ int blk_queue_enter(struct request_queue *q, blk_mq_req_flags_t flags)
 		 */
 		smp_rmb();
 
-		ret = wait_event_interruptible(q->mq_freeze_wq,
+		wait_event(q->mq_freeze_wq,
 			   (atomic_read(&q->mq_freeze_depth) == 0 &&
 			    (preempt || !blk_queue_preempt_only(q))) ||
 			   blk_queue_dying(q));
 		if (blk_queue_dying(q))
 			return -ENODEV;
-		if (ret)
-			return ret;
 	}
 }
 

block/blk-mq.c

@@ -2042,6 +2042,13 @@ static int blk_mq_init_request(struct blk_mq_tag_set *set, struct request *rq,
 
 	seqcount_init(&rq->gstate_seq);
 	u64_stats_init(&rq->aborted_gstate_sync);
+	/*
+	 * start gstate with gen 1 instead of 0, otherwise it will be equal
+	 * to aborted_gstate, and be identified timed out by
+	 * blk_mq_terminate_expired.
+	 */
+	WRITE_ONCE(rq->gstate, MQ_RQ_GEN_INC);
+
 	return 0;
 }
 
@@ -2329,7 +2336,7 @@ static void blk_mq_free_map_and_requests(struct blk_mq_tag_set *set,
 
 static void blk_mq_map_swqueue(struct request_queue *q)
 {
-	unsigned int i;
+	unsigned int i, hctx_idx;
 	struct blk_mq_hw_ctx *hctx;
 	struct blk_mq_ctx *ctx;
 	struct blk_mq_tag_set *set = q->tag_set;
@@ -2346,8 +2353,23 @@ static void blk_mq_map_swqueue(struct request_queue *q)
 
 	/*
 	 * Map software to hardware queues.
+	 *
+	 * If the cpu isn't present, the cpu is mapped to first hctx.
 	 */
 	for_each_possible_cpu(i) {
+		hctx_idx = q->mq_map[i];
+		/* unmapped hw queue can be remapped after CPU topo changed */
+		if (!set->tags[hctx_idx] &&
+		    !__blk_mq_alloc_rq_map(set, hctx_idx)) {
+			/*
+			 * If tags initialization fail for some hctx,
+			 * that hctx won't be brought online.  In this
+			 * case, remap the current ctx to hctx[0] which
+			 * is guaranteed to always have tags allocated
+			 */
+			q->mq_map[i] = 0;
+		}
+
 		ctx = per_cpu_ptr(q->queue_ctx, i);
 		hctx = blk_mq_map_queue(q, i);
 
@@ -2359,8 +2381,21 @@ static void blk_mq_map_swqueue(struct request_queue *q)
 	mutex_unlock(&q->sysfs_lock);
 
 	queue_for_each_hw_ctx(q, hctx, i) {
-		/* every hctx should get mapped by at least one CPU */
-		WARN_ON(!hctx->nr_ctx);
+		/*
+		 * If no software queues are mapped to this hardware queue,
+		 * disable it and free the request entries.
+		 */
+		if (!hctx->nr_ctx) {
+			/* Never unmap queue 0.  We need it as a
+			 * fallback in case of a new remap fails
+			 * allocation
+			 */
+			if (i && set->tags[i])
+				blk_mq_free_map_and_requests(set, i);
+
+			hctx->tags = NULL;
+			continue;
+		}
 
 		hctx->tags = set->tags[i];
 		WARN_ON(!hctx->tags);

block/blk-mq.h

@@ -7,6 +7,9 @@
 
 struct blk_mq_tag_set;
 
+/**
+ * struct blk_mq_ctx - State for a software queue facing the submitting CPUs
+ */
 struct blk_mq_ctx {
 	struct {
 		spinlock_t		lock;

drivers/block/loop.c

@@ -451,25 +451,47 @@ static int lo_req_flush(struct loop_device *lo, struct request *rq)
 static void lo_complete_rq(struct request *rq)
 {
 	struct loop_cmd *cmd = blk_mq_rq_to_pdu(rq);
+	blk_status_t ret = BLK_STS_OK;
 
-	if (unlikely(req_op(cmd->rq) == REQ_OP_READ && cmd->use_aio &&
-		     cmd->ret >= 0 && cmd->ret < blk_rq_bytes(cmd->rq))) {
-		struct bio *bio = cmd->rq->bio;
+	if (!cmd->use_aio || cmd->ret < 0 || cmd->ret == blk_rq_bytes(rq) ||
+	    req_op(rq) != REQ_OP_READ) {
+		if (cmd->ret < 0)
+			ret = BLK_STS_IOERR;
+		goto end_io;
+	}
 
-		bio_advance(bio, cmd->ret);
+	/*
+	 * Short READ - if we got some data, advance our request and
+	 * retry it. If we got no data, end the rest with EIO.
+	 */
+	if (cmd->ret) {
+		blk_update_request(rq, BLK_STS_OK, cmd->ret);
+		cmd->ret = 0;
+		blk_mq_requeue_request(rq, true);
+	} else {
+		if (cmd->use_aio) {
+			struct bio *bio = rq->bio;
+
+			while (bio) {
 				zero_fill_bio(bio);
+				bio = bio->bi_next;
+			}
+		}
+		ret = BLK_STS_IOERR;
+end_io:
+		blk_mq_end_request(rq, ret);
 	}
-
-	blk_mq_end_request(rq, cmd->ret < 0 ? BLK_STS_IOERR : BLK_STS_OK);
 }
 
 static void lo_rw_aio_do_completion(struct loop_cmd *cmd)
 {
+	struct request *rq = blk_mq_rq_from_pdu(cmd);
+
 	if (!atomic_dec_and_test(&cmd->ref))
 		return;
 	kfree(cmd->bvec);
 	cmd->bvec = NULL;
-	blk_mq_complete_request(cmd->rq);
+	blk_mq_complete_request(rq);
 }
 
 static void lo_rw_aio_complete(struct kiocb *iocb, long ret, long ret2)
@@ -487,7 +509,7 @@ static int lo_rw_aio(struct loop_device *lo, struct loop_cmd *cmd,
 {
 	struct iov_iter iter;
 	struct bio_vec *bvec;
-	struct request *rq = cmd->rq;
+	struct request *rq = blk_mq_rq_from_pdu(cmd);
 	struct bio *bio = rq->bio;
 	struct file *file = lo->lo_backing_file;
 	unsigned int offset;
@@ -1702,15 +1724,16 @@ EXPORT_SYMBOL(loop_unregister_transfer);
 static blk_status_t loop_queue_rq(struct blk_mq_hw_ctx *hctx,
 		const struct blk_mq_queue_data *bd)
 {
-	struct loop_cmd *cmd = blk_mq_rq_to_pdu(bd->rq);
-	struct loop_device *lo = cmd->rq->q->queuedata;
+	struct request *rq = bd->rq;
+	struct loop_cmd *cmd = blk_mq_rq_to_pdu(rq);
+	struct loop_device *lo = rq->q->queuedata;
 
-	blk_mq_start_request(bd->rq);
+	blk_mq_start_request(rq);
 
 	if (lo->lo_state != Lo_bound)
 		return BLK_STS_IOERR;
 
-	switch (req_op(cmd->rq)) {
+	switch (req_op(rq)) {
 	case REQ_OP_FLUSH:
 	case REQ_OP_DISCARD:
 	case REQ_OP_WRITE_ZEROES:
@@ -1723,8 +1746,8 @@ static blk_status_t loop_queue_rq(struct blk_mq_hw_ctx *hctx,
 
 	/* always use the first bio's css */
 #ifdef CONFIG_BLK_CGROUP
-	if (cmd->use_aio && cmd->rq->bio && cmd->rq->bio->bi_css) {
-		cmd->css = cmd->rq->bio->bi_css;
+	if (cmd->use_aio && rq->bio && rq->bio->bi_css) {
+		cmd->css = rq->bio->bi_css;
 		css_get(cmd->css);
 	} else
 #endif
@@ -1736,8 +1759,9 @@ static blk_status_t loop_queue_rq(struct blk_mq_hw_ctx *hctx,
 
 static void loop_handle_cmd(struct loop_cmd *cmd)
 {
-	const bool write = op_is_write(req_op(cmd->rq));
-	struct loop_device *lo = cmd->rq->q->queuedata;
+	struct request *rq = blk_mq_rq_from_pdu(cmd);
+	const bool write = op_is_write(req_op(rq));
+	struct loop_device *lo = rq->q->queuedata;
 	int ret = 0;
 
 	if (write && (lo->lo_flags & LO_FLAGS_READ_ONLY)) {
@@ -1745,12 +1769,12 @@ static void loop_handle_cmd(struct loop_cmd *cmd)
 		goto failed;
 	}
 
-	ret = do_req_filebacked(lo, cmd->rq);
+	ret = do_req_filebacked(lo, rq);
  failed:
 	/* complete non-aio request */
 	if (!cmd->use_aio || ret) {
 		cmd->ret = ret ? -EIO : 0;
-		blk_mq_complete_request(cmd->rq);
+		blk_mq_complete_request(rq);
 	}
 }
 
@@ -1767,9 +1791,7 @@ static int loop_init_request(struct blk_mq_tag_set *set, struct request *rq,
 {
 	struct loop_cmd *cmd = blk_mq_rq_to_pdu(rq);
 
-	cmd->rq = rq;
 	kthread_init_work(&cmd->work, loop_queue_work);
-
 	return 0;
 }
 

drivers/block/loop.h

@@ -66,7 +66,6 @@ struct loop_device {
 
 struct loop_cmd {
 	struct kthread_work work;
-	struct request *rq;
 	bool use_aio; /* use AIO interface to handle I/O */
 	atomic_t ref; /* only for aio */
 	long ret;

drivers/block/swim.c

@@ -110,7 +110,7 @@ struct iwm {
 /* Select values for swim_select and swim_readbit */
 
 #define READ_DATA_0	0x074
-#define TWOMEG_DRIVE	0x075
+#define ONEMEG_DRIVE	0x075
 #define SINGLE_SIDED	0x076
 #define DRIVE_PRESENT	0x077
 #define DISK_IN		0x170
@@ -118,9 +118,9 @@ struct iwm {
 #define TRACK_ZERO	0x172
 #define TACHO		0x173
 #define READ_DATA_1	0x174
-#define MFM_MODE	0x175
+#define GCR_MODE	0x175
 #define SEEK_COMPLETE	0x176
-#define ONEMEG_MEDIA	0x177
+#define TWOMEG_MEDIA	0x177
 
 /* Bits in handshake register */
 
@@ -612,7 +612,6 @@ static void setup_medium(struct floppy_state *fs)
 		struct floppy_struct *g;
 		fs->disk_in = 1;
 		fs->write_protected = swim_readbit(base, WRITE_PROT);
-		fs->type = swim_readbit(base, ONEMEG_MEDIA);
 
 		if (swim_track00(base))
 			printk(KERN_ERR
@@ -620,6 +619,9 @@ static void setup_medium(struct floppy_state *fs)
 
 		swim_track00(base);
 
+		fs->type = swim_readbit(base, TWOMEG_MEDIA) ?
+			HD_MEDIA : DD_MEDIA;
+		fs->head_number = swim_readbit(base, SINGLE_SIDED) ? 1 : 2;
 		get_floppy_geometry(fs, 0, &g);
 		fs->total_secs = g->size;
 		fs->secpercyl = g->head * g->sect;
@@ -646,7 +648,7 @@ static int floppy_open(struct block_device *bdev, fmode_t mode)
 
 	swim_write(base, setup, S_IBM_DRIVE  | S_FCLK_DIV2);
 	udelay(10);
-	swim_drive(base, INTERNAL_DRIVE);
+	swim_drive(base, fs->location);
 	swim_motor(base, ON);
 	swim_action(base, SETMFM);
 	if (fs->ejected)
@@ -656,6 +658,8 @@ static int floppy_open(struct block_device *bdev, fmode_t mode)
 		goto out;
 	}
 
+	set_capacity(fs->disk, fs->total_secs);
+
 	if (mode & FMODE_NDELAY)
 		return 0;
 
@@ -727,14 +731,9 @@ static int floppy_ioctl(struct block_device *bdev, fmode_t mode,
 		if (copy_to_user((void __user *) param, (void *) &floppy_type,
 				 sizeof(struct floppy_struct)))
 			return -EFAULT;
-		break;
-
-	default:
-		printk(KERN_DEBUG "SWIM floppy_ioctl: unknown cmd %d\n",
-		       cmd);
-		return -ENOSYS;
-	}
 		return 0;
+	}
+	return -ENOTTY;
 }
 
 static int floppy_getgeo(struct block_device *bdev, struct hd_geometry *geo)
@@ -795,7 +794,7 @@ static struct kobject *floppy_find(dev_t dev, int *part, void *data)
 	struct swim_priv *swd = data;
 	int drive = (*part & 3);
 
-	if (drive > swd->floppy_count)
+	if (drive >= swd->floppy_count)
 		return NULL;
 
 	*part = 0;
@@ -813,10 +812,9 @@ static int swim_add_floppy(struct swim_priv *swd, enum drive_location location)
 
 	swim_motor(base, OFF);
 
-	if (swim_readbit(base, SINGLE_SIDED))
-		fs->head_number = 1;
-	else
+	fs->type = HD_MEDIA;
 	fs->head_number = 2;
+
 	fs->ref_count = 0;
 	fs->ejected = 1;
 
@@ -834,10 +832,12 @@ static int swim_floppy_init(struct swim_priv *swd)
 	/* scan floppy drives */
 
 	swim_drive(base, INTERNAL_DRIVE);
-	if (swim_readbit(base, DRIVE_PRESENT))
+	if (swim_readbit(base, DRIVE_PRESENT) &&
+	    !swim_readbit(base, ONEMEG_DRIVE))
 		swim_add_floppy(swd, INTERNAL_DRIVE);
 	swim_drive(base, EXTERNAL_DRIVE);
-	if (swim_readbit(base, DRIVE_PRESENT))
+	if (swim_readbit(base, DRIVE_PRESENT) &&
+	    !swim_readbit(base, ONEMEG_DRIVE))
 		swim_add_floppy(swd, EXTERNAL_DRIVE);
 
 	/* register floppy drives */
@@ -861,7 +861,6 @@ static int swim_floppy_init(struct swim_priv *swd)
 							      &swd->lock);
 		if (!swd->unit[drive].disk->queue) {
 			err = -ENOMEM;
-			put_disk(swd->unit[drive].disk);
 			goto exit_put_disks;
 		}
 		blk_queue_bounce_limit(swd->unit[drive].disk->queue,
@@ -911,7 +910,7 @@ static int swim_probe(struct platform_device *dev)
 		goto out;
 	}
 
-	swim_base = ioremap(res->start, resource_size(res));
+	swim_base = (struct swim __iomem *)res->start;
 	if (!swim_base) {
 		ret = -ENOMEM;
 		goto out_release_io;
@@ -923,7 +922,7 @@ static int swim_probe(struct platform_device *dev)
 	if (!get_swim_mode(swim_base)) {
 		printk(KERN_INFO "SWIM device not found !\n");
 		ret = -ENODEV;
-		goto out_iounmap;
+		goto out_release_io;
 	}
 
 	/* set platform driver data */
@@ -931,7 +930,7 @@ static int swim_probe(struct platform_device *dev)
 	swd = kzalloc(sizeof(struct swim_priv), GFP_KERNEL);
 	if (!swd) {
 		ret = -ENOMEM;
-		goto out_iounmap;
+		goto out_release_io;
 	}
 	platform_set_drvdata(dev, swd);
 
@@ -945,8 +944,6 @@ static int swim_probe(struct platform_device *dev)
 
 out_kfree:
 	kfree(swd);
-out_iounmap:
-	iounmap(swim_base);
 out_release_io:
 	release_mem_region(res->start, resource_size(res));
 out:
@@ -974,8 +971,6 @@ static int swim_remove(struct platform_device *dev)
 	for (drive = 0; drive < swd->floppy_count; drive++)
 		floppy_eject(&swd->unit[drive]);
 
-	iounmap(swd->base);
-
 	res = platform_get_resource(dev, IORESOURCE_MEM, 0);
 	if (res)
 		release_mem_region(res->start, resource_size(res));

drivers/block/swim3.c

@@ -148,7 +148,7 @@ struct swim3 {
 #define MOTOR_ON	2
 #define RELAX		3	/* also eject in progress */
 #define READ_DATA_0	4
-#define TWOMEG_DRIVE	5
+#define ONEMEG_DRIVE	5
 #define SINGLE_SIDED	6	/* drive or diskette is 4MB type? */
 #define DRIVE_PRESENT	7
 #define DISK_IN		8
@@ -156,9 +156,9 @@ struct swim3 {
 #define TRACK_ZERO	10
 #define TACHO		11
 #define READ_DATA_1	12
-#define MFM_MODE	13
+#define GCR_MODE	13
 #define SEEK_COMPLETE	14
-#define ONEMEG_MEDIA	15
+#define TWOMEG_MEDIA	15
 
 /* Definitions of values used in writing and formatting */
 #define DATA_ESCAPE	0x99

drivers/cdrom/cdrom.c

@@ -2371,7 +2371,7 @@ static int cdrom_ioctl_media_changed(struct cdrom_device_info *cdi,
 	if (!CDROM_CAN(CDC_SELECT_DISC) || arg == CDSL_CURRENT)
 		return media_changed(cdi, 1);
 
-	if ((unsigned int)arg >= cdi->capacity)
+	if (arg >= cdi->capacity)
 		return -EINVAL;
 
 	info = kmalloc(sizeof(*info), GFP_KERNEL);

include/linux/blk-mq.h

@@ -9,6 +9,9 @@
 struct blk_mq_tags;
 struct blk_flush_queue;
 
+/**
+ * struct blk_mq_hw_ctx - State for a hardware queue facing the hardware block device
+ */
 struct blk_mq_hw_ctx {
 	struct {
 		spinlock_t		lock;

include/linux/blkdev.h

@@ -737,6 +737,7 @@ bool blk_queue_flag_test_and_clear(unsigned int flag, struct request_queue *q);
 #define blk_queue_quiesced(q)	test_bit(QUEUE_FLAG_QUIESCED, &(q)->queue_flags)
 #define blk_queue_preempt_only(q)				\
 	test_bit(QUEUE_FLAG_PREEMPT_ONLY, &(q)->queue_flags)
+#define blk_queue_fua(q)	test_bit(QUEUE_FLAG_FUA, &(q)->queue_flags)
 
 extern int blk_set_preempt_only(struct request_queue *q);
 extern void blk_clear_preempt_only(struct request_queue *q);