hyperv: Change the receive buffer size for legacy hosts

Due to a bug in the Hyper-V host verion 2008R2, we need to use a slightly smaller
receive buffer size, otherwise the buffer will not be accepted by the legacy hosts.

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

2 files changed, 6 insertions, 1 deletions

diff --git a/drivers/net/hyperv/hyperv_net.h b/drivers/net/hyperv/hyperv_net.h
index 7d06b4959383..13010b4dae5b 100644
--- a/drivers/net/hyperv/hyperv_net.h
+++ b/drivers/net/hyperv/hyperv_net.h
@@ -513,6 +513,7 @@ struct nvsp_message {
 #define NETVSC_MTU 65536
 
 #define NETVSC_RECEIVE_BUFFER_SIZE              (1024*1024*16)  /* 16MB */
+#define NETVSC_RECEIVE_BUFFER_SIZE_LEGACY       (1024*1024*15)  /* 15MB */
 
 #define NETVSC_RECEIVE_BUFFER_ID                0xcafe
 
diff --git a/drivers/net/hyperv/netvsc.c b/drivers/net/hyperv/netvsc.c
index 1a0280dcba7e..daddea2654ce 100644
--- a/drivers/net/hyperv/netvsc.c
+++ b/drivers/net/hyperv/netvsc.c
@@ -365,6 +365,11 @@ static int netvsc_connect_vsp(struct hv_device *device)
                 goto cleanup;
 
         /* Post the big receive buffer to NetVSP */
+        if (net_device->nvsp_version <= NVSP_PROTOCOL_VERSION_2)
+                net_device->recv_buf_size = NETVSC_RECEIVE_BUFFER_SIZE_LEGACY;
+        else
+                net_device->recv_buf_size = NETVSC_RECEIVE_BUFFER_SIZE;
+
         ret = netvsc_init_recv_buf(device);
 
 cleanup:
@@ -898,7 +903,6 @@ int netvsc_device_add(struct hv_device *device, void *additional_info)
         ndev = net_device->ndev;
 
         /* Initialize the NetVSC channel extension */
-        net_device->recv_buf_size = NETVSC_RECEIVE_BUFFER_SIZE;
         spin_lock_init(&net_device->recv_pkt_list_lock);
 
         INIT_LIST_HEAD(&net_device->recv_pkt_list);