[RFC PATCH 2/4] drivers/net/virtio_net: Changed mergeable buffer length calculation.

From: Andrew Melnychenko
Date: Sun Oct 31 2021 - 01:03:17 EST


Now minimal virtual header length is may include the entire v1 header
if the hash report were populated.

Signed-off-by: Andrew Melnychenko <andrew@xxxxxxxxxx>
---
drivers/net/virtio_net.c | 8 +++++---
1 file changed, 5 insertions(+), 3 deletions(-)

diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c
index b72b21ac8ebd..abca2e93355d 100644
--- a/drivers/net/virtio_net.c
+++ b/drivers/net/virtio_net.c
@@ -393,7 +393,9 @@ static struct sk_buff *page_to_skb(struct virtnet_info *vi,
hdr_p = p;

hdr_len = vi->hdr_len;
- if (vi->mergeable_rx_bufs)
+ if (vi->has_rss_hash_report)
+ hdr_padded_len = sizeof(struct virtio_net_hdr_v1_hash);
+ else if (vi->mergeable_rx_bufs)
hdr_padded_len = sizeof(*hdr);
else
hdr_padded_len = sizeof(struct padded_vnet_hdr);
@@ -1252,7 +1254,7 @@ static unsigned int get_mergeable_buf_len(struct receive_queue *rq,
struct ewma_pkt_len *avg_pkt_len,
unsigned int room)
{
- const size_t hdr_len = sizeof(struct virtio_net_hdr_mrg_rxbuf);
+ const size_t hdr_len = ((struct virtnet_info *)(rq->vq->vdev->priv))->hdr_len;
unsigned int len;

if (room)
@@ -2817,7 +2819,7 @@ static void virtnet_del_vqs(struct virtnet_info *vi)
*/
static unsigned int mergeable_min_buf_len(struct virtnet_info *vi, struct virtqueue *vq)
{
- const unsigned int hdr_len = sizeof(struct virtio_net_hdr_mrg_rxbuf);
+ const unsigned int hdr_len = vi->hdr_len;
unsigned int rq_size = virtqueue_get_vring_size(vq);
unsigned int packet_len = vi->big_packets ? IP_MAX_MTU : vi->dev->max_mtu;
unsigned int buf_len = hdr_len + ETH_HLEN + VLAN_HLEN + packet_len;
--
2.33.1