Copy stable/9 to releng/9.3 as part of the 9.3-RELEASE cycle.

Approved by: re (implicit)
Sponsored by: The FreeBSD Foundation

MFC r260381:

For "nvmecontrol devlist", show namespace sizes in terms of MB instead of
GB to improve granularity of the reporting - especially for namespaces
that are on the order of 1 or 2 GB.

MFC r253476:

Add message when nvd disks are attached and detached.

As part of this commit, add an nvme_strvis() function which borrows
heavily from cam_strvis(). This will allow stripping of
leading/trailing whitespace and also handle unprintable characters
in model/serial numbers. This function goes into a new nvme_util.c
file which is used by both the driver and nvmecontrol.

Approved by: re (kib)
Sponsored by: Intel

MFC r253474:

Fix nvme(4) and nvd(4) to support non 512-byte sector sizes.

Recent testing with QEMU that has variable sector size support for
NVMe uncovered some of these issues. Chatham prototype boards supported
only 512 byte sectors.

Approved by: re (kib)
Sponsored by: Intel

MFC r253459:

Use _PATH_DEV (from paths.h) for the "/dev/" string, rather than
hard-coding it.

Approved by: re (kib)
Sponsored by: Intel

MFC r253437:

Define constants for the lengths of the serial number, model number
and firmware revision in the controller's identify structure.

Also modify consumers of these fields to ensure they only use the
specified number of bytes for their respective fields.

Approved by: re (kib)
Sponsored by: Intel

MFC r253436, r253458:

Simplify open_dev() by returning errno values rather than just 0 or 1.

Also remove stat() call and just rely on errno from open() call to discern
whether dev node exists or not.

Approved by: re (kib)
Sponsored by: Intel

MFC r253109, r253279:

r253109:
Incorporate feedback from bde@ based on r252672 changes:

* Use 0/1 instead of sysexits. Man pages are confusing on this topic,
but 0/1 is sufficient for nvmecontrol.
* Use err function family where possible instead of fprintf/exit.
* Fix some typing errors.
* Clean up some error message inconsistencies.

r253279:
%d should be used for printing int32_t instead of %zd.

clang does not complain about this - only gcc.

Incorporated r253279 prior to MFC timeout because it is required for gcc
builds.

Approved by: re (kib)

MFC r252270:

Create #defines for NVME_CTRLR_PREFIX and NVME_NS_PREFIX for the "nvme"
and "ns" strings, rather than hardcoding the string values throughout the
nvmecontrol code base.

Sponsored by: Intel

MFC r252265:

Break out code related to the devlist command into a separate source file.

Sponsored by: Intel

Break out code related to the devlist command into a separate source file.

Sponsored by: Intel
MFC after: 3 days