Re: [PATCH] tools/memory-model: remove rb-dep, smp_read_barrier_depends, and lockless_dereference

[Peter Zijlstra]

On Mon, Feb 19, 2018 at 12:14:45PM -0500, Alan Stern wrote:
> Note that operations like atomic_add_unless() already include memory 
> barriers.

It is valid for atomic_add_unless() to not imply any barriers when the
addition doesn't happen.