[PATCH 2/3] hv_netvsc: Wait for completion on request NVSP_MSG4_TYPE_SWITCH_DATA_PATH

From: Long Li
Date: Tue Jan 05 2021 - 20:17:28 EST


From: Long Li <longli@xxxxxxxxxxxxx>

The completion indicates if NVSP_MSG4_TYPE_SWITCH_DATA_PATH has been
processed by the VSP. The traffic is steered to VF or synthetic after we
receive this completion.

Signed-off-by: Long Li <longli@xxxxxxxxxxxxx>
---
drivers/net/hyperv/netvsc.c | 34 +++++++++++++++++++++++++++++++--
drivers/net/hyperv/netvsc_drv.c | 1 -
2 files changed, 32 insertions(+), 3 deletions(-)

diff --git a/drivers/net/hyperv/netvsc.c b/drivers/net/hyperv/netvsc.c
index 2350342b961f..237e998d21d1 100644
--- a/drivers/net/hyperv/netvsc.c
+++ b/drivers/net/hyperv/netvsc.c
@@ -37,6 +37,10 @@ void netvsc_switch_datapath(struct net_device *ndev, bool vf)
struct netvsc_device *nv_dev = rtnl_dereference(net_device_ctx->nvdev);
struct nvsp_message *init_pkt = &nv_dev->channel_init_pkt;

+ /* Block sending traffic to VF if it's about to be gone */
+ if (!vf)
+ net_device_ctx->data_path_is_vf = vf;
+
memset(init_pkt, 0, sizeof(struct nvsp_message));
init_pkt->hdr.msg_type = NVSP_MSG4_TYPE_SWITCH_DATA_PATH;
if (vf)
@@ -50,8 +54,11 @@ void netvsc_switch_datapath(struct net_device *ndev, bool vf)

vmbus_sendpacket(dev->channel, init_pkt,
sizeof(struct nvsp_message),
- VMBUS_RQST_ID_NO_RESPONSE,
- VM_PKT_DATA_INBAND, 0);
+ (unsigned long)init_pkt,
+ VM_PKT_DATA_INBAND,
+ VMBUS_DATA_PACKET_FLAG_COMPLETION_REQUESTED);
+ wait_for_completion(&nv_dev->channel_init_wait);
+ net_device_ctx->data_path_is_vf = vf;
}

/* Worker to setup sub channels on initial setup
@@ -756,6 +763,29 @@ static void netvsc_send_completion(struct net_device *ndev,
{
const struct nvsp_message *nvsp_packet = hv_pkt_data(desc);
u32 msglen = hv_pkt_datalen(desc);
+ struct nvsp_message *pkt_rqst;
+ u64 cmd_rqst;
+
+ /* First check if this is a VMBUS completion without data payload */
+ if (!msglen) {
+ cmd_rqst = vmbus_request_addr(&incoming_channel->requestor,
+ (u64)desc->trans_id);
+ if (cmd_rqst == VMBUS_RQST_ERROR) {
+ netdev_err(ndev, "Invalid transaction id\n");
+ return;
+ }
+
+ pkt_rqst = (struct nvsp_message *)cmd_rqst;
+ switch (pkt_rqst->hdr.msg_type) {
+ case NVSP_MSG4_TYPE_SWITCH_DATA_PATH:
+ complete(&net_device->channel_init_wait);
+ break;
+
+ default:
+ netdev_err(ndev, "Unexpected VMBUS completion!!\n");
+ }
+ return;
+ }

/* Ensure packet is big enough to read header fields */
if (msglen < sizeof(struct nvsp_message_header)) {
diff --git a/drivers/net/hyperv/netvsc_drv.c b/drivers/net/hyperv/netvsc_drv.c
index 5dd4f37afa3d..64ae5f4e974e 100644
--- a/drivers/net/hyperv/netvsc_drv.c
+++ b/drivers/net/hyperv/netvsc_drv.c
@@ -2400,7 +2400,6 @@ static int netvsc_vf_changed(struct net_device *vf_netdev)

if (net_device_ctx->data_path_is_vf == vf_is_up)
return NOTIFY_OK;
- net_device_ctx->data_path_is_vf = vf_is_up;

netvsc_switch_datapath(ndev, vf_is_up);
netdev_info(ndev, "Data path switched %s VF: %s\n",
--
2.27.0