On Wed, Feb 03, 2016@01:13:23AM +0100, Mark Jacobson wrote:

1. When you say out-of-tree, do you mean a loadable kernel module?
(My understanding is that the NVMe driver is now part of the mainline
Linux kernel source tree, so I'm a bit confused as to where to nab
that from.)

Yes, a loadable kernel module or a package that can build one. I am not
aware of any publicly available. Perhaps your vendor provides one.

2. Does the upstream 4.4.1 kernel have any of these fixes if I were to
build it myself with the appropriate support ticked off?

The 4.3 kernel has the fixes, and anything newer than that should also
work. I think it was just the 4.2 kernel that had this wrong (will see
if there's are any stable patch candidates).