From: Nick Piggin <[EMAIL PROTECTED]> Date: Sat, 03 Sep 2005 07:22:18 +1000
> This atomic_cmpxchg, unlike a "regular" cmpxchg, has the advantage > that the memory altered should always be going through the atomic_ > accessors, and thus should be implementable with spinlocks. > > See for example, arch/sparc/lib/atomic32.c > > At least, that's what I'm hoping for. Ok, as long as the rule is that all accesses have to go through accessor macros, it would work. This is not true for existing uses of cmpxchg() btw, userland accesses shared locks with the kernel would using any kind of accessors we can control. This means that your atomic_cmpxchg() cannot be used for locking objects shared with userland, as DRM wants, since the hashed spinlock trick does not work in such a case. - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/