David Howells [off-list ref] wrote:

Rather than iterating through all the rest of your patches and saying the same
thing, if there's something in a UAPI header that needs wrapping in __KERNEL__
to exclude it from userspace's use, then it should be transferred to the
non-UAPI variant of that header (which should #include the UAPI variant).

I should mention that there is the odd case where this is difficult to
achieve.  See include/uapi/linux/acct.h for an example...

David