On Wed, Aug 21, 2019 at 01:57:02PM -0400, Vivek Goyal wrote: > From: Stefan Hajnoczi <stefanha@xxxxxxxxxx> > > Although struct dax_device itself is not tied to a block device, some > DAX code assumes there is a block device. Make block devices optional > by allowing bdev to be NULL in commonly used DAX APIs. > > When there is no block device: > * Skip the partition offset calculation in bdev_dax_pgoff() > * Skip the blkdev_issue_zeroout() optimization > > Note that more block device assumptions remain but I haven't reach those > code paths yet. I think this should be split into two patches. For bdev_dax_pgoff I'd much rather have the partition offset if there is on in the daxdev somehow so that we can get rid of the block device entirely. Similarly for dax_range_is_aligned I'd rather have a pure dax way to offload zeroing rather than this bdev hack. In the long run I'd really like to make the bdev vs daxdev in iomap a union instead of having to carry both around.
