Re: Re: [PATCH] rdma/siw: avoid smp_store_mb() on a u64

[Peter Zijlstra]

On Fri, Jul 12, 2019 at 01:05:14PM +0000, Bernard Metzler wrote:
> @@ -1131,6 +1131,10 @@ int siw_poll_cq(struct ib_cq *base_cq, int num_cqe, struct ib_wc *wc)
>   *   number of not reaped CQE's regardless of its notification
>   *   type and current or new CQ notification settings.
>   *
> + * This function gets called only by kernel consumers.
> + * Notification state must immediately become visible to all
> + * associated kernel producers (QP's).

No amount of memory barriers can achieve that goal.