barriers before {req/rsp}_cons = cons?

[Samuel Thibault <samuel.thibault@eu.citrix.com>]

Hello,

In a bunch of places, one can read code like

cons = netif->tx.req_cons;
rmb(); /* Ensure that we see the request before we copy it. */
memcpy(&txreq, RING_GET_REQUEST(&netif->tx, i), sizeof(txreq));
some checks
netif->tx.req_cons = ++cons;

Shouldn't there be a full barrier just before the req_cons assignation?
I guess we are currently not seeing bugs at least because the req will
not be overwriten until we loop in the ring, but it seems to me there
may be a bug here.

Samuel