net/i40e: relax barrier in Tx

To keep ordering of mixed accesses, rte_cio is sufficient.
The rte_io barrier inside the I40E_PCI_REG_WRITE is overkill.[1]

[1] http://inbox.dpdk.org/dev/CALBAE1M-ezVWCjqCZDBw+MMDEC4O9
qf0Kpn89EMdGDajepKoZQ@mail.gmail.com

Fixes: 4861cde46116 ("i40e: new poll mode driver")
Cc: stable@dpdk.org
Signed-off-by: Gavin Hu <gavin.hu@arm.com>
Reviewed-by: Jerin Jacob <jerinj@marvell.com>

diff --git a/drivers/net/i40e/i40e_rxtx.c b/drivers/net/i40e/i40e_rxtx.c
index f6d23c9..fdc1e00 100644 (file)
--- a/drivers/net/i40e/i40e_rxtx.c
+++ b/drivers/net/i40e/i40e_rxtx.c
@@ -1248,7 +1248,8 @@ end_of_tx:
                   (unsigned) txq->port_id, (unsigned) txq->queue_id,
                   (unsigned) tx_id, (unsigned) nb_tx);
 
-       I40E_PCI_REG_WRITE(txq->qtx_tail, tx_id);
+       rte_cio_wmb();
+       I40E_PCI_REG_WRITE_RELAXED(txq->qtx_tail, tx_id);
        txq->tx_tail = tx_id;
 
        return nb_tx;