[RFC] CAM pass(4) patch for NVMe

[Chuck Tuffli]

On Tue, Apr 4, 2017 at 11:13 AM, Warner Losh <imp at bsdimp.com> wrote:
...
> Fair Enough. I'd thought 0xffff was the magic number :). However, you
> raise a good point.
>
> Grep tells me all the xflags are actually unused. So we could use it,
> but after chatting with Scott Long, I'm not sure that we should.
>
> However, I think Jim's idea of having a separate command for commands
> for the I/O queue and commands for the admin queue might be the better
> part of valor here. I'd initially read Jim's mail as use #defines for
> the xflags values, but that's not at all what he was saying.
>
> The code change would be a bit bigger, but not by a lot. It's super
> easy to add new XPT_ function code.

OK, I'll head down that path and add a new XPT opcode XPT_NVME_ADMIN
and helper macro cam_fill_nvmeadmin() which would be used for Admin
commands. The existing XPT_NVME_IO would be used for NVM/IO commands.
Both opcodes would use the ccb_nvmeio structure unless there are
objections .... ?

--chuck