[PATCH] Document Linux's memory barriers [try #2]

[David Howells]

Alan Cox <alan at redhat.com> wrote:

> spin_unlock ensures that local CPU writes before the lock are visible
> to all processors before the lock is dropped but it has no effect on 
> I/O ordering. Just a need for clarity.

So I can't use spinlocks in my driver to make sure two different CPUs don't
interfere with each other when trying to communicate with a device because the
spinlocks don't guarantee that I/O operations will stay in effect within the
locking section?

David