Re: [PATCH 3/3] early_printk: Add simple serialization to early_vprintk()

[Peter Zijlstra]

On Wed, Oct 04, 2017 at 07:17:45AM -0700, Paul E. McKenney wrote:
> If you use READ_ONCE(), then all architectures I know of enforce
> full ordering for accesses to a single variable.  (If you don't use
> READ_ONCE(), then in theory Itanium can reorder reads.)  Me, I would
> argue for WRITE_ONCE() as well to prevent store tearing.

Note that the stores are either cmpxchg() or smp_store_release() both of
which imply a WRITE_ONCE().