[ofa-general] Re: [PATCH 15/28] IB/ipath - add barrier before updating WC head in shared memory

[Roland Dreier]

 >  	wc->queue[head].port_num = entry->port_num;
 > +	wmb();
 >  	wc->head = next;

Please add comments explaining these barriers... maybe something like

       /* Make sure queue entry contents are visible before head index update */

also I notice that the latest libibipathverbs git tree (which hasn't
been touched for 3 months) does not seem to have the analogous read
memory barrier when polling CQ contents.

 - R.