device_dax - export a 'resource' attribute for dax devices

[quanxian]

Description:
device_dax devices need to export a resource attribute so that libdaxctl
can use it to find the address range for the device. This is required for
onlining/offlining memory associated with a device in the system-ram mode
(i.e. kmem).

Target Release: 19.10
Target Kernel: 5.3

[Ubuntu Kernel Bot (ubuntu-kernel-bot)]

This bug is missing log files that will aid in diagnosing the problem. While running an Ubuntu kernel (not a mainline or third-party kernel) please enter the following command in a terminal window:

apport-collect 1835347

and then change the status of the bug to 'Confirmed'.

If, due to the nature of the issue you have encountered, you are unable to run this command, please add a comment stating that fact and change the bug status to 'Confirmed'.

This change has been made by an automated script, maintained by the Ubuntu Kernel Team.

[quanxian (quanxian-wang)]

Merged in v5.3-rc1

commit 40cdc60ac16a42eb4e013f84d0e7aa1d6ee060d3
Author: Vishal Verma <email address hidden>
Date: Thu Jun 20 18:40:38 2019 -0600

device-dax: Add a 'resource' attribute

device-dax based devices were missing a 'resource' attribute to indicate
the physical address range contributed by the device in question. This
information is desirable to userspace tooling that may want to use the
dax device as system-ram, and wants to selectively hotplug and online
the memory blocks associated with a given device.

Without this, the tooling would have to parse /proc/iomem for the memory
ranges contributed by dax devices, which can be a workaround, but it is
far easier to provide this information in the sysfs hierarchy.

Cc: Dave Hansen <email address hidden>
Cc: Dan Williams <email address hidden>
Signed-off-by: Vishal Verma <email address hidden>
Signed-off-by: Dan Williams <email address hidden>