Writing an mtd user module

[adr]

Having written a driver module for the Dreamcast flash cartridge/vmu, I am now 
attempting to write a user module that works with the default fs on the 
Dreamcast flash (see http://mc.pp.se/dc/vms/flashmem.html if you are 
interested in knowing more about that).

Anyway, I am struggling with the documentaion (which, as I found with the 
driver was way out of date) and the code.

Looking at the mtdblock driver, register_mtd_user(&notifier); only seems to 
get called when devfs is being used, yet the documentation implies it should 
be called every time.

What have I missed here?