nvme/023: use character device for nvme smart-log command

[yizhanglinux]

The nvme-cli v2.12 changed to use the character device for nvme smart-log command, update nvme/023 to use char device to avoid the case failure.

$ nvme smart-log /dev/nvme0n1
smart log: No such device or address
$ nvme smart-log /dev/nvme0
Smart Log for NVME device:nvme0 namespace-id:ffffffff critical_warning : 0
temperature : -459 °F (0 K)
available_spare : 0%
available_spare_threshold : 0%
percentage_used : 0%
endurance group critical warning summary: 0
Data Units Read : 20 (10.24 MB)
Data Units Written : 0 (0.00 B)
host_read_commands : 142
host_write_commands : 0
controller_busy_time : 0
power_cycles : 0
power_on_hours : 0
unsafe_shutdowns : 0
media_errors : 0
num_err_log_entries : 0
Warning Temperature Time : 0
Critical Composite Temperature Time : 0
Thermal Management T1 Trans Count : 0
Thermal Management T2 Trans Count : 0
Thermal Management T1 Total Time : 0
Thermal Management T2 Total Time : 0

Link: #172

[igaw]

LGTM. Thanks!

[kawasaki]

Ah, I wasn't aware of this PR and the related issue #172. And did the investigation in parallel...
As I reported to linux-nvme, there are two unclear points:

1. The man page of "nvme smart-log" command advertises it works for namespace block devices.
2. When libnvme is built without liburing, "nvme smart-log" command works for the namespace block devices.

Based on these, I'm still not sure if really nvme-cli drops the namespace block device support for the "nvme smart-log" command.

[yizhanglinux]

Thanks for the investigation. Let's hold the change until we have the final conclusion for "nvme smart-log."

[igaw]

We have a couple of places we are discussing things. I'll keep linux-nvme/nvme-cli#2829 updated what's going on in libnvme/nvme-cli resp. the mailing list.

[igaw]

I've applied the fix for libnvme.

The io_uring usage is borderline useful IMO. Maybe we should document that it is not necessary to be enabled for distro packages.

[yizhanglinux]

Close it now.