Here we also need AcpiAttachData(handle, acpi_fake_objhandler, child); so that acpi_get_device() can work in nvdimm_find_by_handle()

see note below about the loop variable name.

Do we need to flush already created children ?

Why -1 ?

Please do not name non-integer loop variable 'i'.

Do we need to clear other already created spa's ?

This '{' should be on the new line, alone.

_* are C-std reserved names, better not use them at all.

return (*a - *b);

You want to mask the value after dereferencing the pointer, right ? I would write it as

val &= mask;

on the next line.

More important, this code potentially accesses unaligned types, esp. when you do the trick with fetching uint16_t and passing UINT16_MAX for the mask. This only works on x86, and even there it works by chance.

There is no need in {} around single-line block, usually.

And there the body block is multi-line, so {} are warranted by style.

Several more {} vs. no-{} below, I did not marked them.

the child devices and spas get destroyed on detach, which I think covers the case you mention.

You're right, I think the -1 was wrong.

This comment is obsoleted by the nvdimm root device's own ivars.

oops, messed up a space here.

changed this to bcopy to handle the unaligned access.

Think I got them all, sorry for the simple mistakes.