Fix NVMe's use of XPT_GDEV_TYPE

[chuck_tuffli.net]

Summary

This patch changes the way XPT_GDEV_TYPE works for NVMe. The current ccb_getdev structure includes pointers to the NVMe Identify Controller and Namespace structures, but these are kernel virtual addresses which are not accessible from user space.

As an alternative, the patch removes these pointers from ccb_getdev and adds two new types to ccb_dev_advinfo to retrieve the Identify Controller (CDAI_TYPE_NVME_CNTRL) and Namespace (CDAI_TYPE_NVME_NS) data structures.

[chuck_tuffli.net]

Fixed white-space problem with cam_ccb.h

[rpokala]

Please regenerate the diffs w/ proper context. See https://wiki.freebsd.org/action/show/Phabricator for details on how to do that.

[chuck_tuffli.net]

Add full diff context per feedback.

[rpokala]

sys/cam/nvme/nvme_da.c

704 ↗

(On Diff #27697)

It appears that cgd is only used in this function for setting these two variables, and for some #if 0-ed out code later on. Since it's no longer used, can you remove it entirely?

[chuck_tuffli.net]

sys/cam/nvme/nvme_da.c

704 ↗

(On Diff #27697)

If it weren't for the ifdef'd out quirk code, I would have taken it out. Can we let @imp make the call?

[imp]

Remove it. If we need it again, it can be added back.

[chuck_tuffli.net]

Removed ccb_getdev references and ifdef'd out quirk code in ndaregister

[rpokala]

LGTM, but @imp should have the final say.

[imp]

Except for padding.

sys/cam/cam_ccb.h

363–364 ↗

(On Diff #27767)

should we replace this with void *padding[2]; instead?

[chuck_tuffli.net]

sys/cam/cam_ccb.h

363–364 ↗

(On Diff #27767)

Works for me. I will plan on this unless someone has an objection.