netdev - [PATCH net] virtio-net: use NETIF_F_GRO_HW instead of NETIF_F

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Date:   Tue, 17 Aug 2021 10:03:38 +0800
From:   Jason Wang <jasowang@...hat.com>
To:     mst@...hat.com, jasowang@...hat.com, davem@...emloft.net,
        kuba@...nel.org
Cc:     willemb@...gle.com, virtualization@...ts.linux-foundation.org,
        netdev@...r.kernel.org, linux-kernel@...r.kernel.org,
        ivan@...stigetransportation.com, xiangxia.m.yue@...il.com
Subject: [PATCH net] virtio-net: use NETIF_F_GRO_HW instead of NETIF_F_LRO

Commit a02e8964eaf92 ("virtio-net: ethtool configurable LRO") tries to
advertise LRO on behalf of the guest offloading features and allow the
administrator to enable and disable those features via ethtool.

This may lead several issues:

- For the device that doesn't support control guest offloads, the
  "LRO" can't be disabled so we will get a warn in the
  dev_disable_lro()
- For the device that have the control guest offloads, the guest
  offloads were disabled in the case of bridge etc which may slow down
  the traffic.

Fixing this by using NETIF_F_GRO_HW instead. Though the spec does not
guaranteed to be re-segmented as original explicitly now, we can add
that to the spec and then we can catch the bad configuration and
setup.

Fixes: a02e8964eaf92 ("virtio-net: ethtool configurable LRO")
Signed-off-by: Jason Wang <jasowang@...hat.com>
---
 drivers/net/virtio_net.c | 14 +++++++-------
 1 file changed, 7 insertions(+), 7 deletions(-)

diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c
index 0416a7e00914..10c382b08bce 100644
--- a/drivers/net/virtio_net.c
+++ b/drivers/net/virtio_net.c
@@ -63,7 +63,7 @@ static const unsigned long guest_offloads[] = {
 	VIRTIO_NET_F_GUEST_CSUM
 };
 
-#define GUEST_OFFLOAD_LRO_MASK ((1ULL << VIRTIO_NET_F_GUEST_TSO4) | \
+#define GUEST_OFFLOAD_GRO_HW_MASK ((1ULL << VIRTIO_NET_F_GUEST_TSO4) | \
 				(1ULL << VIRTIO_NET_F_GUEST_TSO6) | \
 				(1ULL << VIRTIO_NET_F_GUEST_ECN)  | \
 				(1ULL << VIRTIO_NET_F_GUEST_UFO))
@@ -2481,7 +2481,7 @@ static int virtnet_xdp_set(struct net_device *dev, struct bpf_prog *prog,
 	        virtio_has_feature(vi->vdev, VIRTIO_NET_F_GUEST_ECN) ||
 		virtio_has_feature(vi->vdev, VIRTIO_NET_F_GUEST_UFO) ||
 		virtio_has_feature(vi->vdev, VIRTIO_NET_F_GUEST_CSUM))) {
-		NL_SET_ERR_MSG_MOD(extack, "Can't set XDP while host is implementing LRO/CSUM, disable LRO/CSUM first");
+		NL_SET_ERR_MSG_MOD(extack, "Can't set XDP while host is implementing GRO_HW/CSUM, disable GRO_HW/CSUM first");
 		return -EOPNOTSUPP;
 	}
 
@@ -2612,15 +2612,15 @@ static int virtnet_set_features(struct net_device *dev,
 	u64 offloads;
 	int err;
 
-	if ((dev->features ^ features) & NETIF_F_LRO) {
+	if ((dev->features ^ features) & NETIF_F_GRO_HW) {
 		if (vi->xdp_enabled)
 			return -EBUSY;
 
-		if (features & NETIF_F_LRO)
+		if (features & NETIF_F_GRO_HW)
 			offloads = vi->guest_offloads_capable;
 		else
 			offloads = vi->guest_offloads_capable &
-				   ~GUEST_OFFLOAD_LRO_MASK;
+				   ~GUEST_OFFLOAD_GRO_HW_MASK;
 
 		err = virtnet_set_guest_offloads(vi, offloads);
 		if (err)
@@ -3100,9 +3100,9 @@ static int virtnet_probe(struct virtio_device *vdev)
 		dev->features |= NETIF_F_RXCSUM;
 	if (virtio_has_feature(vdev, VIRTIO_NET_F_GUEST_TSO4) ||
 	    virtio_has_feature(vdev, VIRTIO_NET_F_GUEST_TSO6))
-		dev->features |= NETIF_F_LRO;
+		dev->features |= NETIF_F_GRO_HW;
 	if (virtio_has_feature(vdev, VIRTIO_NET_F_CTRL_GUEST_OFFLOADS))
-		dev->hw_features |= NETIF_F_LRO;
+		dev->hw_features |= NETIF_F_GRO_HW;
 
 	dev->vlan_features = dev->features;
 
-- 
2.25.1