On Friday 12 July 2002 01:52, Sandy Harris wrote:
> Oliver Xymoron wrote:
> >
> > On Thu, 11 Jul 2002, Daniel Phillips wrote:
> >
> > > I was thinking of something as simple as:
> > >
> > > #define spin_assert_locked(LOCK) BUG_ON(!spin_is_locked(LOCK))
> > >
> > > but in truth I'd be happy regardless of the internal implementation. A note
> > > on names: Linus likes to shout the names of his BUG macros. I've never been
> > > one for shouting, but it's not my kernel, and anyway, I'm happy he now likes
> > > asserts. I bet he'd like it more spelled like this though:
> > >
> > > MUST_HOLD(&lock);
> >
> > I prefer that form too.
>
> Is it worth adding MUST_NOT_HOLD(&lock) in an attempt to catch potential
> deadlocks?
>
> Say that if two or more of locks A, B and C are to be taken, then
> they must be taken in that order. You might then have code like:
>
> MUST_NOT_HOLD(&lock_B) ;
> MUST_NOT_HOLD(&lock_C) ;
> spinlock(&lock_A) ;
>
> I think you need a separate asertion for this !MUST_NOT_HOLD(&lock)
> has different semantics.
MUST_NOT_HOLD is already in Jesse's patch he posted earlier today,
though I imagine it would be used rarely if at all.
!MUST_NOT_HOLD(&lock) is an error, MUST_NOT_HOLD is a statement not a
function.
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This archive was generated by hypermail 2b29 : Mon Jul 15 2002 - 22:00:21 EST