Messages in this thread | | | From | Daniel Phillips <> | Subject | Re: spinlock assertion macros | Date | Fri, 12 Jul 2002 02:56:59 +0200 |
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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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