1 files changed, 195 insertions, 190 deletions

diff --git a/block/genhd.c b/block/genhd.c
index 298ee78c1bda..567549a011d1 100644
--- a/block/genhd.c
+++ b/block/genhd.c
@@ -29,6 +29,23 @@
 
 static struct kobject *block_depr;
 
+/*
+ * Unique, monotonically increasing sequential number associated with block
+ * devices instances (i.e. incremented each time a device is attached).
+ * Associating uevents with block devices in userspace is difficult and racy:
+ * the uevent netlink socket is lossy, and on slow and overloaded systems has
+ * a very high latency.
+ * Block devices do not have exclusive owners in userspace, any process can set
+ * one up (e.g. loop devices). Moreover, device names can be reused (e.g. loop0
+ * can be reused again and again).
+ * A userspace process setting up a block device and watching for its events
+ * cannot thus reliably tell whether an event relates to the device it just set
+ * up or another earlier instance with the same name.
+ * This sequential number allows userspace processes to solve this problem, and
+ * uniquely associate an uevent to the lifetime to a device.
+ */
+static atomic64_t diskseq;
+
 /* for extended dynamic devt allocation, currently only one major is used */
 #define NR_EXT_DEVT		(1 << MINORBITS)
 static DEFINE_IDA(ext_devt_ida);
@@ -60,7 +77,8 @@ bool set_capacity_and_notify(struct gendisk *disk, sector_t size)
 	 * initial capacity during probing.
 	 */
 	if (size == capacity ||
-	    (disk->flags & (GENHD_FL_UP | GENHD_FL_HIDDEN)) != GENHD_FL_UP)
+	    !disk_live(disk) ||
+	    (disk->flags & GENHD_FL_HIDDEN))
 		return false;
 
 	pr_info("%s: detected capacity change from %lld to %lld\n",
@@ -78,11 +96,17 @@ bool set_capacity_and_notify(struct gendisk *disk, sector_t size)
 EXPORT_SYMBOL_GPL(set_capacity_and_notify);
 
 /*
- * Format the device name of the indicated disk into the supplied buffer and
- * return a pointer to that same buffer for convenience.
+ * Format the device name of the indicated block device into the supplied buffer
+ * and return a pointer to that same buffer for convenience.
+ *
+ * Note: do not use this in new code, use the %pg specifier to sprintf and
+ * printk insted.
  */
-char *disk_name(struct gendisk *hd, int partno, char *buf)
+const char *bdevname(struct block_device *bdev, char *buf)
 {
+	struct gendisk *hd = bdev->bd_disk;
+	int partno = bdev->bd_partno;
+
 	if (!partno)
 		snprintf(buf, BDEVNAME_SIZE, "%s", hd->disk_name);
 	else if (isdigit(hd->disk_name[strlen(hd->disk_name)-1]))
@@ -92,11 +116,6 @@ char *disk_name(struct gendisk *hd, int partno, char *buf)
 
 	return buf;
 }
-
-const char *bdevname(struct block_device *bdev, char *buf)
-{
-	return disk_name(bdev->bd_disk, bdev->bd_partno, buf);
-}
 EXPORT_SYMBOL(bdevname);
 
 static void part_stat_read_all(struct block_device *part,
@@ -294,54 +313,19 @@ void unregister_blkdev(unsigned int major, const char *name)
 
 EXPORT_SYMBOL(unregister_blkdev);
 
-/**
- * blk_mangle_minor - scatter minor numbers apart
- * @minor: minor number to mangle
- *
- * Scatter consecutively allocated @minor number apart if MANGLE_DEVT
- * is enabled.  Mangling twice gives the original value.
- *
- * RETURNS:
- * Mangled value.
- *
- * CONTEXT:
- * Don't care.
- */
-static int blk_mangle_minor(int minor)
-{
-#ifdef CONFIG_DEBUG_BLOCK_EXT_DEVT
-	int i;
-
-	for (i = 0; i < MINORBITS / 2; i++) {
-		int low = minor & (1 << i);
-		int high = minor & (1 << (MINORBITS - 1 - i));
-		int distance = MINORBITS - 1 - 2 * i;
-
-		minor ^= low | high;	/* clear both bits */
-		low <<= distance;	/* swap the positions */
-		high >>= distance;
-		minor |= low | high;	/* and set */
-	}
-#endif
-	return minor;
-}
-
 int blk_alloc_ext_minor(void)
 {
 	int idx;
 
 	idx = ida_alloc_range(&ext_devt_ida, 0, NR_EXT_DEVT, GFP_KERNEL);
-	if (idx < 0) {
-		if (idx == -ENOSPC)
-			return -EBUSY;
-		return idx;
-	}
-	return blk_mangle_minor(idx);
+	if (idx == -ENOSPC)
+		return -EBUSY;
+	return idx;
 }
 
 void blk_free_ext_minor(unsigned int minor)
 {
-	ida_free(&ext_devt_ida, blk_mangle_minor(minor));
+	ida_free(&ext_devt_ida, minor);
 }
 
 static char *bdevt_str(dev_t devt, char *buf)
@@ -390,78 +374,20 @@ static void disk_scan_partitions(struct gendisk *disk)
 		blkdev_put(bdev, FMODE_READ);
 }
 
-static void register_disk(struct device *parent, struct gendisk *disk,
-			  const struct attribute_group **groups)
-{
-	struct device *ddev = disk_to_dev(disk);
-	int err;
-
-	ddev->parent = parent;
-
-	dev_set_name(ddev, "%s", disk->disk_name);
-
-	/* delay uevents, until we scanned partition table */
-	dev_set_uevent_suppress(ddev, 1);
-
-	if (groups) {
-		WARN_ON(ddev->groups);
-		ddev->groups = groups;
-	}
-	if (device_add(ddev))
-		return;
-	if (!sysfs_deprecated) {
-		err = sysfs_create_link(block_depr, &ddev->kobj,
-					kobject_name(&ddev->kobj));
-		if (err) {
-			device_del(ddev);
-			return;
-		}
-	}
-
-	/*
-	 * avoid probable deadlock caused by allocating memory with
-	 * GFP_KERNEL in runtime_resume callback of its all ancestor
-	 * devices
-	 */
-	pm_runtime_set_memalloc_noio(ddev, true);
-
-	disk->part0->bd_holder_dir =
-		kobject_create_and_add("holders", &ddev->kobj);
-	disk->slave_dir = kobject_create_and_add("slaves", &ddev->kobj);
-
-	if (disk->flags & GENHD_FL_HIDDEN)
-		return;
-
-	disk_scan_partitions(disk);
-
-	/* announce the disk and partitions after all partitions are created */
-	dev_set_uevent_suppress(ddev, 0);
-	disk_uevent(disk, KOBJ_ADD);
-
-	if (disk->queue->backing_dev_info->dev) {
-		err = sysfs_create_link(&ddev->kobj,
-			  &disk->queue->backing_dev_info->dev->kobj,
-			  "bdi");
-		WARN_ON(err);
-	}
-}
-
 /**
- * __device_add_disk - add disk information to kernel list
+ * device_add_disk - add disk information to kernel list
  * @parent: parent device for the disk
  * @disk: per-device partitioning information
  * @groups: Additional per-device sysfs groups
- * @register_queue: register the queue if set to true
  *
  * This function registers the partitioning information in @disk
  * with the kernel.
- *
- * FIXME: error handling
  */
-static void __device_add_disk(struct device *parent, struct gendisk *disk,
-			      const struct attribute_group **groups,
-			      bool register_queue)
+int device_add_disk(struct device *parent, struct gendisk *disk,
+		     const struct attribute_group **groups)
+
 {
+	struct device *ddev = disk_to_dev(disk);
 	int ret;
 
 	/*
@@ -470,8 +396,7 @@ static void __device_add_disk(struct device *parent, struct gendisk *disk,
 	 * elevator if one is needed, that is, for devices requesting queue
 	 * registration.
 	 */
-	if (register_queue)
-		elevator_init_mq(disk->queue);
+	elevator_init_mq(disk->queue);
 
 	/*
 	 * If the driver provides an explicit major number it also must provide
@@ -481,7 +406,8 @@ static void __device_add_disk(struct device *parent, struct gendisk *disk,
 	 * and all partitions from the extended dev_t space.
 	 */
 	if (disk->major) {
-		WARN_ON(!disk->minors);
+		if (WARN_ON(!disk->minors))
+			return -EINVAL;
 
 		if (disk->minors > DISK_MAX_PARTS) {
 			pr_err("block: can't allocate more than %d partitions\n",
@@ -489,21 +415,65 @@ static void __device_add_disk(struct device *parent, struct gendisk *disk,
 			disk->minors = DISK_MAX_PARTS;
 		}
 	} else {
-		WARN_ON(disk->minors);
+		if (WARN_ON(disk->minors))
+			return -EINVAL;
 
 		ret = blk_alloc_ext_minor();
-		if (ret < 0) {
-			WARN_ON(1);
-			return;
-		}
+		if (ret < 0)
+			return ret;
 		disk->major = BLOCK_EXT_MAJOR;
-		disk->first_minor = MINOR(ret);
+		disk->first_minor = ret;
 		disk->flags |= GENHD_FL_EXT_DEVT;
 	}
 
-	disk->flags |= GENHD_FL_UP;
+	ret = disk_alloc_events(disk);
+	if (ret)
+		goto out_free_ext_minor;
 
-	disk_alloc_events(disk);
+	/* delay uevents, until we scanned partition table */
+	dev_set_uevent_suppress(ddev, 1);
+
+	ddev->parent = parent;
+	ddev->groups = groups;
+	dev_set_name(ddev, "%s", disk->disk_name);
+	if (!(disk->flags & GENHD_FL_HIDDEN))
+		ddev->devt = MKDEV(disk->major, disk->first_minor);
+	ret = device_add(ddev);
+	if (ret)
+		goto out_disk_release_events;
+	if (!sysfs_deprecated) {
+		ret = sysfs_create_link(block_depr, &ddev->kobj,
+					kobject_name(&ddev->kobj));
+		if (ret)
+			goto out_device_del;
+	}
+
+	/*
+	 * avoid probable deadlock caused by allocating memory with
+	 * GFP_KERNEL in runtime_resume callback of its all ancestor
+	 * devices
+	 */
+	pm_runtime_set_memalloc_noio(ddev, true);
+
+	ret = blk_integrity_add(disk);
+	if (ret)
+		goto out_del_block_link;
+
+	disk->part0->bd_holder_dir =
+		kobject_create_and_add("holders", &ddev->kobj);
+	if (!disk->part0->bd_holder_dir)
+		goto out_del_integrity;
+	disk->slave_dir = kobject_create_and_add("slaves", &ddev->kobj);
+	if (!disk->slave_dir)
+		goto out_put_holder_dir;
+
+	ret = bd_register_pending_holders(disk);
+	if (ret < 0)
+		goto out_put_slave_dir;
+
+	ret = blk_register_queue(disk);
+	if (ret)
+		goto out_put_slave_dir;
 
 	if (disk->flags & GENHD_FL_HIDDEN) {
 		/*
@@ -513,48 +483,56 @@ static void __device_add_disk(struct device *parent, struct gendisk *disk,
 		disk->flags |= GENHD_FL_SUPPRESS_PARTITION_INFO;
 		disk->flags |= GENHD_FL_NO_PART_SCAN;
 	} else {
-		struct backing_dev_info *bdi = disk->queue->backing_dev_info;
-		struct device *dev = disk_to_dev(disk);
-
-		/* Register BDI before referencing it from bdev */
-		dev->devt = MKDEV(disk->major, disk->first_minor);
-		ret = bdi_register(bdi, "%u:%u",
+		ret = bdi_register(disk->bdi, "%u:%u",
 				   disk->major, disk->first_minor);
-		WARN_ON(ret);
-		bdi_set_owner(bdi, dev);
-		bdev_add(disk->part0, dev->devt);
-	}
-	register_disk(parent, disk, groups);
-	if (register_queue)
-		blk_register_queue(disk);
+		if (ret)
+			goto out_unregister_queue;
+		bdi_set_owner(disk->bdi, ddev);
+		ret = sysfs_create_link(&ddev->kobj,
+					&disk->bdi->dev->kobj, "bdi");
+		if (ret)
+			goto out_unregister_bdi;
 
-	/*
-	 * Take an extra ref on queue which will be put on disk_release()
-	 * so that it sticks around as long as @disk is there.
-	 */
-	if (blk_get_queue(disk->queue))
-		set_bit(GD_QUEUE_REF, &disk->state);
-	else
-		WARN_ON_ONCE(1);
+		bdev_add(disk->part0, ddev->devt);
+		disk_scan_partitions(disk);
 
-	disk_add_events(disk);
-	blk_integrity_add(disk);
-}
+		/*
+		 * Announce the disk and partitions after all partitions are
+		 * created. (for hidden disks uevents remain suppressed forever)
+		 */
+		dev_set_uevent_suppress(ddev, 0);
+		disk_uevent(disk, KOBJ_ADD);
+	}
 
-void device_add_disk(struct device *parent, struct gendisk *disk,
-		     const struct attribute_group **groups)
+	disk_update_readahead(disk);
+	disk_add_events(disk);
+	return 0;
 
-{
-	__device_add_disk(parent, disk, groups, true);
+out_unregister_bdi:
+	if (!(disk->flags & GENHD_FL_HIDDEN))
+		bdi_unregister(disk->bdi);
+out_unregister_queue:
+	blk_unregister_queue(disk);
+out_put_slave_dir:
+	kobject_put(disk->slave_dir);
+out_put_holder_dir:
+	kobject_put(disk->part0->bd_holder_dir);
+out_del_integrity:
+	blk_integrity_del(disk);
+out_del_block_link:
+	if (!sysfs_deprecated)
+		sysfs_remove_link(block_depr, dev_name(ddev));
+out_device_del:
+	device_del(ddev);
+out_disk_release_events:
+	disk_release_events(disk);
+out_free_ext_minor:
+	if (disk->major == BLOCK_EXT_MAJOR)
+		blk_free_ext_minor(disk->first_minor);
+	return WARN_ON_ONCE(ret); /* keep until all callers handle errors */
 }
 EXPORT_SYMBOL(device_add_disk);
 
-void device_add_disk_no_queue_reg(struct device *parent, struct gendisk *disk)
-{
-	__device_add_disk(parent, disk, NULL, false);
-}
-EXPORT_SYMBOL(device_add_disk_no_queue_reg);
-
 /**
  * del_gendisk - remove the gendisk
  * @disk: the struct gendisk to remove
@@ -578,26 +556,20 @@ void del_gendisk(struct gendisk *disk)
 {
 	might_sleep();
 
-	if (WARN_ON_ONCE(!disk->queue))
+	if (WARN_ON_ONCE(!disk_live(disk) && !(disk->flags & GENHD_FL_HIDDEN)))
 		return;
 
 	blk_integrity_del(disk);
 	disk_del_events(disk);
 
 	mutex_lock(&disk->open_mutex);
-	disk->flags &= ~GENHD_FL_UP;
+	remove_inode_hash(disk->part0->bd_inode);
 	blk_drop_partitions(disk);
 	mutex_unlock(&disk->open_mutex);
 
 	fsync_bdev(disk->part0);
 	__invalidate_device(disk->part0, true);
 
-	/*
-	 * Unhash the bdev inode for this device so that it can't be looked
-	 * up any more even if openers still hold references to it.
-	 */
-	remove_inode_hash(disk->part0->bd_inode);
-
 	set_capacity(disk, 0);
 
 	if (!(disk->flags & GENHD_FL_HIDDEN)) {
@@ -607,7 +579,7 @@ void del_gendisk(struct gendisk *disk)
 		 * Unregister bdi before releasing device numbers (as they can
 		 * get reused and we'd get clashes in sysfs).
 		 */
-		bdi_unregister(disk->queue->backing_dev_info);
+		bdi_unregister(disk->bdi);
 	}
 
 	blk_unregister_queue(disk);
@@ -683,7 +655,6 @@ void __init printk_all_partitions(void)
 	while ((dev = class_dev_iter_next(&iter))) {
 		struct gendisk *disk = dev_to_disk(dev);
 		struct block_device *part;
-		char name_buf[BDEVNAME_SIZE];
 		char devt_buf[BDEVT_SIZE];
 		unsigned long idx;
 
@@ -703,11 +674,10 @@ void __init printk_all_partitions(void)
 		xa_for_each(&disk->part_tbl, idx, part) {
 			if (!bdev_nr_sectors(part))
 				continue;
-			printk("%s%s %10llu %s %s",
+			printk("%s%s %10llu %pg %s",
 			       bdev_is_partition(part) ? "  " : "",
 			       bdevt_str(part->bd_dev, devt_buf),
-			       bdev_nr_sectors(part) >> 1,
-			       disk_name(disk, part->bd_partno, name_buf),
+			       bdev_nr_sectors(part) >> 1, part,
 			       part->bd_meta_info ?
 					part->bd_meta_info->uuid : "");
 			if (bdev_is_partition(part))
@@ -785,7 +755,6 @@ static int show_partition(struct seq_file *seqf, void *v)
 	struct gendisk *sgp = v;
 	struct block_device *part;
 	unsigned long idx;
-	char buf[BDEVNAME_SIZE];
 
 	/* Don't show non-partitionable removeable devices or empty devices */
 	if (!get_capacity(sgp) || (!disk_max_parts(sgp) &&
@@ -798,10 +767,9 @@ static int show_partition(struct seq_file *seqf, void *v)
 	xa_for_each(&sgp->part_tbl, idx, part) {
 		if (!bdev_nr_sectors(part))
 			continue;
-		seq_printf(seqf, "%4d  %7d %10llu %s\n",
+		seq_printf(seqf, "%4d  %7d %10llu %pg\n",
 			   MAJOR(part->bd_dev), MINOR(part->bd_dev),
-			   bdev_nr_sectors(part) >> 1,
-			   disk_name(sgp, part->bd_partno, buf));
+			   bdev_nr_sectors(part) >> 1, part);
 	}
 	rcu_read_unlock();
 	return 0;
@@ -968,6 +936,14 @@ static ssize_t disk_discard_alignment_show(struct device *dev,
 	return sprintf(buf, "%d\n", queue_discard_alignment(disk->queue));
 }
 
+static ssize_t diskseq_show(struct device *dev,
+			    struct device_attribute *attr, char *buf)
+{
+	struct gendisk *disk = dev_to_disk(dev);
+
+	return sprintf(buf, "%llu\n", disk->diskseq);
+}
+
 static DEVICE_ATTR(range, 0444, disk_range_show, NULL);
 static DEVICE_ATTR(ext_range, 0444, disk_ext_range_show, NULL);
 static DEVICE_ATTR(removable, 0444, disk_removable_show, NULL);
@@ -980,6 +956,7 @@ static DEVICE_ATTR(capability, 0444, disk_capability_show, NULL);
 static DEVICE_ATTR(stat, 0444, part_stat_show, NULL);
 static DEVICE_ATTR(inflight, 0444, part_inflight_show, NULL);
 static DEVICE_ATTR(badblocks, 0644, disk_badblocks_show, disk_badblocks_store);
+static DEVICE_ATTR(diskseq, 0444, diskseq_show, NULL);
 
 #ifdef CONFIG_FAIL_MAKE_REQUEST
 ssize_t part_fail_show(struct device *dev,
@@ -1025,6 +1002,7 @@ static struct attribute *disk_attrs[] = {
 	&dev_attr_events.attr,
 	&dev_attr_events_async.attr,
 	&dev_attr_events_poll_msecs.attr,
+	&dev_attr_diskseq.attr,
 #ifdef CONFIG_FAIL_MAKE_REQUEST
 	&dev_attr_fail.attr,
 #endif
@@ -1074,17 +1052,24 @@ static void disk_release(struct device *dev)
 
 	might_sleep();
 
-	if (MAJOR(dev->devt) == BLOCK_EXT_MAJOR)
-		blk_free_ext_minor(MINOR(dev->devt));
 	disk_release_events(disk);
 	kfree(disk->random);
 	xa_destroy(&disk->part_tbl);
-	if (test_bit(GD_QUEUE_REF, &disk->state) && disk->queue)
-		blk_put_queue(disk->queue);
-	bdput(disk->part0);	/* frees the disk */
+	disk->queue->disk = NULL;
+	blk_put_queue(disk->queue);
+	iput(disk->part0->bd_inode);	/* frees the disk */
+}
+
+static int block_uevent(struct device *dev, struct kobj_uevent_env *env)
+{
+	struct gendisk *disk = dev_to_disk(dev);
+
+	return add_uevent_var(env, "DISKSEQ=%llu", disk->diskseq);
 }
+
 struct class block_class = {
 	.name		= "block",
+	.dev_uevent	= block_uevent,
 };
 
 static char *block_devnode(struct device *dev, umode_t *mode,
@@ -1116,7 +1101,6 @@ static int diskstats_show(struct seq_file *seqf, void *v)
 {
 	struct gendisk *gp = v;
 	struct block_device *hd;
-	char buf[BDEVNAME_SIZE];
 	unsigned int inflight;
 	struct disk_stats stat;
 	unsigned long idx;
@@ -1139,15 +1123,14 @@ static int diskstats_show(struct seq_file *seqf, void *v)
 		else
 			inflight = part_in_flight(hd);
 
-		seq_printf(seqf, "%4d %7d %s "
+		seq_printf(seqf, "%4d %7d %pg "
 			   "%lu %lu %lu %u "
 			   "%lu %lu %lu %u "
 			   "%u %u %u "
 			   "%lu %lu %lu %u "
 			   "%lu %u"
 			   "\n",
-			   MAJOR(hd->bd_dev), MINOR(hd->bd_dev),
-			   disk_name(gp, hd->bd_partno, buf),
+			   MAJOR(hd->bd_dev), MINOR(hd->bd_dev), hd,
 			   stat.ios[STAT_READ],
 			   stat.merges[STAT_READ],
 			   stat.sectors[STAT_READ],
@@ -1239,17 +1222,25 @@ dev_t blk_lookup_devt(const char *name, int partno)
 	return devt;
 }
 
-struct gendisk *__alloc_disk_node(int minors, int node_id)
+struct gendisk *__alloc_disk_node(struct request_queue *q, int node_id,
+		struct lock_class_key *lkclass)
 {
 	struct gendisk *disk;
 
+	if (!blk_get_queue(q))
+		return NULL;
+
 	disk = kzalloc_node(sizeof(struct gendisk), GFP_KERNEL, node_id);
 	if (!disk)
-		return NULL;
+		goto out_put_queue;
+
+	disk->bdi = bdi_alloc(node_id);
+	if (!disk->bdi)
+		goto out_free_disk;
 
 	disk->part0 = bdev_alloc(disk, 0);
 	if (!disk->part0)
-		goto out_free_disk;
+		goto out_free_bdi;
 
 	disk->node_id = node_id;
 	mutex_init(&disk->open_mutex);
@@ -1257,23 +1248,33 @@ struct gendisk *__alloc_disk_node(int minors, int node_id)
 	if (xa_insert(&disk->part_tbl, 0, disk->part0, GFP_KERNEL))
 		goto out_destroy_part_tbl;
 
-	disk->minors = minors;
 	rand_initialize_disk(disk);
 	disk_to_dev(disk)->class = &block_class;
 	disk_to_dev(disk)->type = &disk_type;
 	device_initialize(disk_to_dev(disk));
+	inc_diskseq(disk);
+	disk->queue = q;
+	q->disk = disk;
+	lockdep_init_map(&disk->lockdep_map, "(bio completion)", lkclass, 0);
+#ifdef CONFIG_BLOCK_HOLDER_DEPRECATED
+	INIT_LIST_HEAD(&disk->slave_bdevs);
+#endif
 	return disk;
 
 out_destroy_part_tbl:
 	xa_destroy(&disk->part_tbl);
-	bdput(disk->part0);
+	iput(disk->part0->bd_inode);
+out_free_bdi:
+	bdi_put(disk->bdi);
 out_free_disk:
 	kfree(disk);
+out_put_queue:
+	blk_put_queue(q);
 	return NULL;
 }
 EXPORT_SYMBOL(__alloc_disk_node);
 
-struct gendisk *__blk_alloc_disk(int node)
+struct gendisk *__blk_alloc_disk(int node, struct lock_class_key *lkclass)
 {
 	struct request_queue *q;
 	struct gendisk *disk;
@@ -1282,12 +1283,11 @@ struct gendisk *__blk_alloc_disk(int node)
 	if (!q)
 		return NULL;
 
-	disk = __alloc_disk_node(0, node);
+	disk = __alloc_disk_node(q, node, lkclass);
 	if (!disk) {
 		blk_cleanup_queue(q);
 		return NULL;
 	}
-	disk->queue = q;
 	return disk;
 }
 EXPORT_SYMBOL(__blk_alloc_disk);
@@ -1362,3 +1362,8 @@ int bdev_read_only(struct block_device *bdev)
 	return bdev->bd_read_only || get_disk_ro(bdev->bd_disk);
 }
 EXPORT_SYMBOL(bdev_read_only);
+
+void inc_diskseq(struct gendisk *disk)
+{
+	disk->diskseq = atomic64_inc_return(&diskseq);
+}