[Bug] Crystal Ridge: Fix device-dax sysfs duplicate name warning / failure

[quanxian]

Fix warnings of the form...
WARNING: CPU: 10 PID: 4983 at fs/sysfs/dir.c:31 sysfs_warn_dup+0x62/0x80
sysfs: cannot create duplicate filename '/class/dax/dax12.0'
Call Trace:
dump_stack+0x63/0x86
__warn+0xcb/0xf0
warn_slowpath_fmt+0x5a/0x80
? kernfs_path_from_node+0x4f/0x60
sysfs_warn_dup+0x62/0x80
sysfs_do_create_link_sd.isra.2+0x97/0xb0
sysfs_create_link+0x25/0x40
device_add+0x266/0x630
devm_create_dax_dev+0x2cf/0x340 [dax]
dax_pmem_probe+0x1f5/0x26e [dax_pmem]
nvdimm_bus_probe+0x71/0x120
...by reusing the namespace id for the device-dax instance name.
Now that we have decided that there will never by more than one
device-dax instance per libnvdimm-namespace parent device [1], we can
directly reuse the namepace ids. There are some possible follow-on
cleanups, but those are saved for a later patch to simplify the -stable
backport.
[1]: https://lists.01.org/pipermail/linux-nvdimm/2016-December/008266.html
Fixes: 98a29c39dc68 ("libnvdimm, namespace: allow creation of multiple pmem...")
Cc: Jeff Moyer <email address hidden>
Cc: <email address hidden>
Reported-by: Dariusz Dokupil <email address hidden>
Signed-off-by: Dan Williams <email address hidden>

Target Release: 17.10
Target Kernel: 4.13

[quanxian (quanxian-wang)]

bbb3be170ac2 device-dax: fix sysfs duplicate warnings

[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 1712249

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.

[[e-mail] (pragyan)]

This bug was found by Red Hat and fixed/code upstreamed by Jeff Moyer from Red Hat. This is being added to Canonical for Ubuntu to pick up.

[Leann Ogasawara (leannogasawara)]

Marking this Fix Released for Artful 17.10 as it contains a 4.13 based kernel containing the commit referenced in comment #1.

$ git describe --contains bbb3be170ac2891526ad07b18af7db226879a8e7
v4.13~241^2

commit bbb3be170ac2891526ad07b18af7db226879a8e7
Author: Dan Williams <email address hidden>
Date: Tue Jul 18 17:49:14 2017 -0700

    device-dax: fix sysfs duplicate warnings