On Fri, Dec 08, 2006 at 11:37:45AM -0800, Linus Torvalds wrote: > > > On Fri, 8 Dec 2006, Russell King wrote: > > > > I utterly disagree. I could code atomic_add() as: > > Sure. And Alpha could do that too. If you write the C code a specific way, > you can make it work. That does NOT mean that you can expose it widely as > a portable interface - it's still just a very _nonportable_ interface that > you use internally within one architecture to implement other interfaces.
However, nothing stops you wrapping the non-portable nature of ll/sc up into the store part though. If you can efficiently implement cmpxchg inside an ll/sc based portable interface (yes you can) and you can implement problematical ll/sc structures inside a cmpxchg() interface, you can do it either way around. Only one way doesn't penalise broken ll/sc based implementations though. That is the essence of my argument. -- Russell King Linux kernel 2.6 ARM Linux - http://www.arm.linux.org.uk/ maintainer of: - 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/
