net/enic: fix Rx queue init after restarting a device

If you stop, then start a port that had already received some packets,
the NIC could fetch discriptors from the wrong location. This could
effectivly reduce the size of the Rx queue by a random amount and
cause packet drop or reduced performance.

Reset the NIC fetch index to 0 when allocating and posting mbuf
addresses to the NIC.

Fixes: 947d860c821f ("enic: improve Rx performance")

Signed-off-by: John Daley <johndale@cisco.com>
Reviewed-by: Nelson Escobar <neescoba@cisco.com>

diff --git a/drivers/net/enic/enic_main.c b/drivers/net/enic/enic_main.c
index dc831b4..0475cc1 100644 (file)
--- a/drivers/net/enic/enic_main.c
+++ b/drivers/net/enic/enic_main.c
@@ -334,6 +334,7 @@ enic_alloc_rx_queue_mbufs(struct enic *enic, struct vnic_rq *rq)
        dev_debug(enic, "port=%u, qidx=%u, Write %u posted idx, %u sw held\n",
                enic->port_id, rq->index, rq->posted_index, rq->rx_nb_hold);
        iowrite32(rq->posted_index, &rq->ctrl->posted_index);
+       iowrite32(0, &rq->ctrl->fetch_index);
        rte_rmb();
 
        return 0;