On Wed, May 15, 2019 at 12:28 PM Vivek Goyal <vgoyal@xxxxxxxxxx> 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. > Is there a generic object that non-block-based filesystems reference for physical storage as a bdev stand-in? I assume "sector_t" is still the common type for addressing filesystem capacity? It just seems to me that we should stop pretending that the filesystem-dax facility requires block devices and try to move this functionality to generically use a dax device across all interfaces.