vhost: make error handling consistent in Rx path

In the non-mergeable receive case, when copy_mbuf_to_desc()
call fails the packet is skipped, the corresponding used element
len field is set to vnet header size, and it continues with next
packet/desc. It could be a problem because it does not know why
it failed, and assume the desc buffer is large enough.

In mergeable receive case, when copy_mbuf_to_desc_mergeable()
fails, packets burst is simply stopped.

This patch makes the non-mergeable error path to behave as the
mergeable one, as it seems the safest way. Also, doing this way
will simplify pending IOTLB miss requests handling.

Signed-off-by: Maxime Coquelin <maxime.coquelin@redhat.com>
Acked-by: Yuanhan Liu <yliu@fridaylinux.org>

diff --git a/lib/librte_vhost/virtio_net.c b/lib/librte_vhost/virtio_net.c
index f8732df..59ff6c8 100644 (file)
--- a/lib/librte_vhost/virtio_net.c
+++ b/lib/librte_vhost/virtio_net.c
@@ -374,11 +374,8 @@ virtio_dev_rx(struct virtio_net *dev, uint16_t queue_id,
 
                err = copy_mbuf_to_desc(dev, vq, descs, pkts[i], desc_idx, sz);
                if (unlikely(err)) {
-                       used_idx = (start_idx + i) & (vq->size - 1);
-                       vq->used->ring[used_idx].len = dev->vhost_hlen;
-                       vhost_log_used_vring(dev, vq,
-                               offsetof(struct vring_used, ring[used_idx]),
-                               sizeof(vq->used->ring[used_idx]));
+                       count = i;
+                       break;
                }
 
                if (i + 1 < count)