net/virtio: check mbuf is direct when using any layout

The commit dd856dfcb9e74 introduced an optimization that prepends virtio
header to mbuf data. It can be used when the tx mbuf is writeable, so we
need to check that the mbuf is direct (i.e. it embeds its own data).

Fixes: dd856dfcb9e7 ("virtio: use any layout on Tx")

Signed-off-by: Olivier Matz <olivier.matz@6wind.com>
Acked-by: Yuanhan Liu <yuanhan.liu@linux.intel.com>

diff --git a/drivers/net/virtio/virtio_rxtx.c b/drivers/net/virtio/virtio_rxtx.c
index 04f6832..2411dba 100644 (file)
--- a/drivers/net/virtio/virtio_rxtx.c
+++ b/drivers/net/virtio/virtio_rxtx.c
@@ -873,6 +873,7 @@ virtio_xmit_pkts(void *tx_queue, struct rte_mbuf **tx_pkts, uint16_t nb_pkts)
                /* optimize ring usage */
                if (vtpci_with_feature(hw, VIRTIO_F_ANY_LAYOUT) &&
                    rte_mbuf_refcnt_read(txm) == 1 &&
+                   RTE_MBUF_DIRECT(txm) &&
                    txm->nb_segs == 1 &&
                    rte_pktmbuf_headroom(txm) >= hdr_size &&
                    rte_is_aligned(rte_pktmbuf_mtod(txm, char *),