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

[Ira Weiny]

On Mon, Oct 18, 2021 at 06:40:46AM +0200, Christoph Hellwig wrote:
> 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 at 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.
>  	 */

NIT: this comment needs to be updated as well.

Ira

> -	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;

[snip]