On Thu, 23 Aug 2007, Nick Piggin wrote:

OK, but we'd have some kind of functions that are called not to
serialise the CPUs, but to serialise the IO. It would be up to
the calling code to already provide CPU synchronisation.

serialize_io(); / unserialize_io(); / a nicer name

We could call it "mmiowb()", for example?

Radical idea, I know.

If we could pass in some kind of relevant resoure (eg. the IO
memory or device or something), then we might even be able to
put debug checks there to ensure two CPUs are never inside the
same critical IO section at once.

We could certainly give it the spinlock as an argument.

		Linus