[PATCH 6/9] block: add a mark_dead holder operation

[Christoph Hellwig <hch@xxxxxx>]

Add a mark_dead method to blk_holder_ops that is called from blk_mark_disk_dead
to notify the holder that the block device it is using has been marked dead.

Signed-off-by: Christoph Hellwig <hch@xxxxxx>
---
 block/genhd.c          | 24 ++++++++++++++++++++++++
 include/linux/blkdev.h |  1 +
 2 files changed, 25 insertions(+)

diff --git a/block/genhd.c b/block/genhd.c
index d1c673b967c254..af97a4ef1e926c 100644
--- a/block/genhd.c
+++ b/block/genhd.c
@@ -575,6 +575,28 @@ int __must_check device_add_disk(struct device *parent, struct gendisk *disk,
 }
 EXPORT_SYMBOL(device_add_disk);
 
+static void blk_report_disk_dead(struct gendisk *disk)
+{
+	struct block_device *bdev;
+	unsigned long idx;
+
+	rcu_read_lock();
+	xa_for_each(&disk->part_tbl, idx, bdev) {
+		if (!kobject_get_unless_zero(&bdev->bd_device.kobj))
+			continue;
+		rcu_read_unlock();
+
+		mutex_lock(&bdev->bd_holder_lock);
+		if (bdev->bd_holder_ops && bdev->bd_holder_ops->mark_dead)
+			bdev->bd_holder_ops->mark_dead(bdev);
+		mutex_unlock(&bdev->bd_holder_lock);
+
+		put_device(&bdev->bd_device);
+		rcu_read_lock();
+	}
+	rcu_read_unlock();
+}
+
 /**
  * blk_mark_disk_dead - mark a disk as dead
  * @disk: disk to mark as dead
@@ -602,6 +624,8 @@ void blk_mark_disk_dead(struct gendisk *disk)
 	 * Prevent new I/O from crossing bio_queue_enter().
 	 */
 	blk_queue_start_drain(disk->queue);
+
+	blk_report_disk_dead(disk);
 }
 EXPORT_SYMBOL_GPL(blk_mark_disk_dead);
 
diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h
index 3f41f8c9b103cf..9706bec2be16a5 100644
--- a/include/linux/blkdev.h
+++ b/include/linux/blkdev.h
@@ -1469,6 +1469,7 @@ void blkdev_show(struct seq_file *seqf, off_t offset);
 #endif
 
 struct blk_holder_ops {
+	void (*mark_dead)(struct block_device *bdev);
 };
 
 struct block_device *blkdev_get_by_dev(dev_t dev, fmode_t mode, void *holder,
-- 
2.39.2