Re: Must check what?

From: Vadim Lobanov
Date: Wed Oct 04 2006 - 16:59:00 EST


On Wednesday 04 October 2006 12:43, Andrew Morton wrote:
> > > It should have a slot for documenting caller-provided locking
> > > requirements too. And for permissible calling-contexts. They're all
> > > part of the caller-provided environment, and these two tend to be a
> > > heck of a lot more subtle than the function's formal arguments.
> >
> > Indeed. And reference count assumptions. It's almost like we want a
> > pre-condition assertion ...
>
> We have might_sleep(), assert_spin_locked(), BUG_ON(!irqs_disabled()), etc.
>
> I like assertions personally. If we had something like:
>
> void foo(args)
> {
> locals;
>
> assert_irqs_enabled();
> assert_spin_locked(some_lock);
> assert_in_atomic();
> assert_mutex_locked(some_mutex);
>
> then we get documentation which is (optionally) checked at runtime - best
> of both worlds. Better than doing it in kernel-doc. Automatically
> self-updating (otherwise kernels go BUG).

Uhoh! How much is that going to hurt runtime? :) It actually seems to me like
this should be doable by static code analysis tools without terribly much
pain (in the relative sense of the term). Or am I wrong on this thought?

> And we still need to document those return values in English.

Definitely.

-- Vadim Lobanov
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