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: drm-fsl-dcu-for-next~2603^2~390 X-Git-Url: http://git.agner.ch/gitweb/?p=linux-drm-fsl-dcu.git;a=commitdiff_plain;h=f9cbce34c34bcc05ea0dd78c8999bfe88b5b6b86 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 dd4544085db3..26cd14ccf4d5 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 358475ed9b59..b855ba9a507d 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 236aeb76ef22..2e40417a8087 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 */