On Thu, Jan 16, 2020 at 10:39 AM Vivek Goyal <vgoyal@xxxxxxxxxx> wrote: > > On Thu, Jan 16, 2020 at 10:09:46AM -0800, Dan Williams wrote: > > On Wed, Jan 15, 2020 at 1:08 PM Jeff Moyer <jmoyer@xxxxxxxxxx> wrote: > > > > > > Hi, Dan, > > > > > > Dan Williams <dan.j.williams@xxxxxxxxx> writes: > > > > > > > I'm going to take a look at how hard it would be to develop a kpartx > > > > fallback in udev. If that can live across the driver transition then > > > > maybe this can be a non-event for end users that already have that > > > > udev update deployed. > > > > > > I just wanted to remind you that label-less dimms still exist, and are > > > still being shipped. For those devices, the only way to subdivide the > > > storage is via partitioning. > > > > True, but if kpartx + udev can make this transparent then I don't > > think users lose any functionality. They just gain a device-mapper > > dependency. > > So udev rules will trigger when a /dev/pmemX device shows up and run > kpartx which in turn will create dm-linear devices and device nodes > will show up in /dev/mapper/pmemXpY. > > IOW, /dev/pmemXpY device nodes will be gone. So if any of the scripts or > systemd unit files are depenent on /dev/pmemXpY, these will still be > broken out of the box and will have to be modified to use device nodes > in /dev/mapper/ directory instead. Do I understand it right, Or I missed > the idea completely. No, I'd write the udev rule to create links from /dev/pmemXpY to the /dev/mapper device, and that rule would be gated by a new pmem device attribute to trigger when kpartx needs to run vs the kernel native partitions.
