Though it doesn't seem specifically documented in [style] or
//w.n.o/Documentation/kernel, it is clear enough that the
convention for global symbols in module 'foo' is always

foofurbish
fooenfranchise
foo_frob

and so on.  What's less clear is the preferred convention
for foo's private functions and structures:

static foo_frob
static _foo_frob
static frob

The last seems like it could be annoying in ddb, which sees even
private symbols. But otherwise it makes sense when the symbols
are, after all, private.

I might prefer the second to the first just because it gives a
visual clue that it's not something exposed. But is there an
official guideline for this?

-Chap