Re: [PATCH 03/11] dax: simplify the dax_device <-> gendisk association

Replace the dax_host_hash with an xarray indexed by the pointer value
of the gendisk, and require explicitl calls from the block drivers that
want to associate their gendisk with a dax_device.

Signed-off-by: Christoph Hellwig <hch@lst.de>
---
 drivers/dax/bus.c            |   2 +-
 drivers/dax/super.c          | 106 +++++++++--------------------------
 drivers/md/dm.c              |   6 +-
 drivers/nvdimm/pmem.c        |   8 ++-
 drivers/s390/block/dcssblk.c |  11 +++-
 fs/fuse/virtio_fs.c          |   2 +-
 include/linux/dax.h          |  19 +++++--
 7 files changed, 60 insertions(+), 94 deletions(-)

diff --git a/drivers/dax/bus.c b/drivers/dax/bus.c
index 6cc4da4c713d9..6d91b0186e3be 100644
--- a/drivers/dax/bus.c
+++ b/drivers/dax/bus.c

@@ -1326,7 +1326,7 @@ struct dev_dax *devm_create_dev_dax(struct dev_dax_data *data)
 	 * No 'host' or dax_operations since there is no access to this
 	 * device outside of mmap of the resulting character device.
 	 */

-	dax_dev = alloc_dax(dev_dax, NULL, NULL, DAXDEV_F_SYNC);
+	dax_dev = alloc_dax(dev_dax, NULL, DAXDEV_F_SYNC);
 	if (IS_ERR(dax_dev)) {
 		rc = PTR_ERR(dax_dev);
 		goto err_alloc_dax;