hyperv: Add processing of MTU reduced by the host

If the host uses packet encapsulation feature, the MTU may be reduced by the
host due to headroom reservation for encapsulation. This patch handles this
new MTU value.

Signed-off-by: Haiyang Zhang <haiyangz@microsoft.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/drivers/net/hyperv/netvsc.c b/drivers/net/hyperv/netvsc.c
index 7d76c9523395e5b5137784189d902d9cb1ecaed5..6b463117dcaca45f6130a0b6f4573d8946bc41ec 100644 (file)
--- a/drivers/net/hyperv/netvsc.c
+++ b/drivers/net/hyperv/netvsc.c
@@ -440,7 +440,8 @@ static int negotiate_nvsp_ver(struct hv_device *device,
        /* NVSPv2 only: Send NDIS config */
        memset(init_packet, 0, sizeof(struct nvsp_message));
        init_packet->hdr.msg_type = NVSP_MSG2_TYPE_SEND_NDIS_CONFIG;
-       init_packet->msg.v2_msg.send_ndis_config.mtu = net_device->ndev->mtu;
+       init_packet->msg.v2_msg.send_ndis_config.mtu = net_device->ndev->mtu +
+                                                      ETH_HLEN;
        init_packet->msg.v2_msg.send_ndis_config.capability.ieee8021q = 1;
 
        ret = vmbus_sendpacket(device->channel, init_packet,

diff --git a/drivers/net/hyperv/netvsc_drv.c b/drivers/net/hyperv/netvsc_drv.c
index 3295e4ee9dbb19ee821370833e545ac944366610..15d82eda0baf4141465addd6207c6202f09f2543 100644 (file)
--- a/drivers/net/hyperv/netvsc_drv.c
+++ b/drivers/net/hyperv/netvsc_drv.c
@@ -699,9 +699,10 @@ static int netvsc_change_mtu(struct net_device *ndev, int mtu)
                return -ENODEV;
 
        if (nvdev->nvsp_version >= NVSP_PROTOCOL_VERSION_2)
-               limit = NETVSC_MTU;
+               limit = NETVSC_MTU - ETH_HLEN;
 
-       if (mtu < 68 || mtu > limit)
+       /* Hyper-V hosts don't support MTU < ETH_DATA_LEN (1500) */
+       if (mtu < ETH_DATA_LEN || mtu > limit)
                return -EINVAL;
 
        nvdev->start_remove = true;

diff --git a/drivers/net/hyperv/rndis_filter.c b/drivers/net/hyperv/rndis_filter.c
index ccce6f24b009c797b777f94d690e1c76e382e136..7b2c5d1e9bad1b21747d4310324d8d51e7a3000f 100644 (file)
--- a/drivers/net/hyperv/rndis_filter.c
+++ b/drivers/net/hyperv/rndis_filter.c
@@ -998,6 +998,7 @@ int rndis_filter_device_add(struct hv_device *dev,
        int t;
        struct ndis_recv_scale_cap rsscap;
        u32 rsscap_size = sizeof(struct ndis_recv_scale_cap);
+       u32 mtu, size;
 
        rndis_device = get_rndis_device();
        if (!rndis_device)
@@ -1029,6 +1030,14 @@ int rndis_filter_device_add(struct hv_device *dev,
                return ret;
        }
 
+       /* Get the MTU from the host */
+       size = sizeof(u32);
+       ret = rndis_filter_query_device(rndis_device,
+                                       RNDIS_OID_GEN_MAXIMUM_FRAME_SIZE,
+                                       &mtu, &size);
+       if (ret == 0 && size == sizeof(u32))
+               net_device->ndev->mtu = mtu;
+
        /* Get the mac address */
        ret = rndis_filter_query_device_mac(rndis_device);
        if (ret != 0) {