From: Haiyang Zhang Date: Mon, 6 Jul 2015 21:11:37 +0000 (-0700) Subject: hv_netvsc: Add support to set MTU reservation from guest side X-Git-Tag: v4.3-rc1~96^2~390 X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=f9cbce34c34bcc05ea0dd78c8999bfe88b5b6b86;p=thirdparty%2Fkernel%2Fstable.git hv_netvsc: Add support to set MTU reservation from guest side When packet encapsulation is in use, the MTU needs to be reduced for headroom reservation. The existing code takes the updated MTU value only from the host side. But vSwitch extensions, such as Open vSwitch, require the flexibility to change the MTU to different values from within a guest during the lifecycle of a vNIC, when the encapsulation protocol is changed. The patch supports this kind of MTU changes. Signed-off-by: Haiyang Zhang Reviewed-by: K. Y. Srinivasan Signed-off-by: David S. Miller --- diff --git a/drivers/net/hyperv/hyperv_net.h b/drivers/net/hyperv/hyperv_net.h index dd4544085db32..26cd14ccf4d56 100644 --- a/drivers/net/hyperv/hyperv_net.h +++ b/drivers/net/hyperv/hyperv_net.h @@ -589,6 +589,7 @@ struct nvsp_message { #define NETVSC_MTU 65536 +#define NETVSC_MTU_MIN 68 #define NETVSC_RECEIVE_BUFFER_SIZE (1024*1024*16) /* 16MB */ #define NETVSC_RECEIVE_BUFFER_SIZE_LEGACY (1024*1024*15) /* 15MB */ diff --git a/drivers/net/hyperv/netvsc_drv.c b/drivers/net/hyperv/netvsc_drv.c index 358475ed9b596..b855ba9a507d5 100644 --- a/drivers/net/hyperv/netvsc_drv.c +++ b/drivers/net/hyperv/netvsc_drv.c @@ -743,8 +743,7 @@ static int netvsc_change_mtu(struct net_device *ndev, int mtu) if (nvdev->nvsp_version >= NVSP_PROTOCOL_VERSION_2) limit = NETVSC_MTU - ETH_HLEN; - /* Hyper-V hosts don't support MTU < ETH_DATA_LEN (1500) */ - if (mtu < ETH_DATA_LEN || mtu > limit) + if (mtu < NETVSC_MTU_MIN || 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 236aeb76ef224..2e40417a80878 100644 --- a/drivers/net/hyperv/rndis_filter.c +++ b/drivers/net/hyperv/rndis_filter.c @@ -1054,7 +1054,7 @@ int rndis_filter_device_add(struct hv_device *dev, ret = rndis_filter_query_device(rndis_device, RNDIS_OID_GEN_MAXIMUM_FRAME_SIZE, &mtu, &size); - if (ret == 0 && size == sizeof(u32)) + if (ret == 0 && size == sizeof(u32) && mtu < net_device->ndev->mtu) net_device->ndev->mtu = mtu; /* Get the mac address */