[PATCH] virtio: check mbuf is direct when using any layout

[PATCH] virtio: check mbuf is direct when using any layout

[Olivier Matz]

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: dd856dfcb9e74 "virtio: use any layout on Tx"

Signed-off-by: Olivier Matz <olivier.matz@6wind.com>
---
 drivers/net/virtio/virtio_rxtx.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/drivers/net/virtio/virtio_rxtx.c b/drivers/net/virtio/virtio_rxtx.c
index ef21d8e..ae28634 100644
--- a/drivers/net/virtio/virtio_rxtx.c
+++ b/drivers/net/virtio/virtio_rxtx.c
@@ -886,6 +886,7 @@ 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 *),
-- 
2.8.0.rc3

Re: [PATCH] virtio: check mbuf is direct when using any layout

[Yuanhan Liu]

On Mon, May 09, 2016 at 06:19:35PM +0200, Olivier Matz wrote:
> 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: dd856dfcb9e74 "virtio: use any layout on Tx"

Missing "()" here. Fixed and applied to dpdk-next-virtio.

Thanks.

	--yliu