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[1/3,Utopic,LTS,SRU,v2] hyperv: Add processing of MTU reduced by the host

Message ID 1444152573-8655-2-git-send-email-tim.gardner@canonical.com
State New
Headers show

Commit Message

Tim Gardner Oct. 6, 2015, 5:29 p.m. UTC 
From: Haiyang Zhang <haiyangz@microsoft.com>

BugLink: http://bugs.launchpad.net/bugs/1494431

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>
(cherry picked from commit 4d3c9d37f77566b04216dfc9a6513082002d7a1f)
Signed-off-by: Tim Gardner <tim.gardner@canonical.com>
---
 drivers/net/hyperv/netvsc.c       | 3 ++-
 drivers/net/hyperv/netvsc_drv.c   | 5 +++--
 drivers/net/hyperv/rndis_filter.c | 9 +++++++++
 3 files changed, 14 insertions(+), 3 deletions(-)
diff mbox

Patch

diff --git a/drivers/net/hyperv/netvsc.c b/drivers/net/hyperv/netvsc.c
index 349fb3d..fab49e3 100644
--- a/drivers/net/hyperv/netvsc.c
+++ b/drivers/net/hyperv/netvsc.c
@@ -431,7 +431,8 @@  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 7e33318..e88d694 100644
--- a/drivers/net/hyperv/netvsc_drv.c
+++ b/drivers/net/hyperv/netvsc_drv.c
@@ -690,9 +690,10 @@  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 99c527a..d1b2e03 100644
--- a/drivers/net/hyperv/rndis_filter.c
+++ b/drivers/net/hyperv/rndis_filter.c
@@ -1016,6 +1016,7 @@  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)
@@ -1047,6 +1048,14 @@  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) {