hyperv: Increase the buffer length for netvsc_channel_cb()

When the buffer is too small for a packet from VMBus, a bigger buffer will be
allocated in netvsc_channel_cb() and retry reading the packet from VMBus.
Increasing this buffer size will reduce the retry overhead.

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

2 files changed, 16 insertions, 4 deletions

diff --git a/drivers/net/hyperv/hyperv_net.h b/drivers/net/hyperv/hyperv_net.h
index d5e07def6a59..2f48f790c9b4 100644
--- a/drivers/net/hyperv/hyperv_net.h
+++ b/drivers/net/hyperv/hyperv_net.h
@@ -591,7 +591,7 @@ struct nvsp_message {
 
 #define NETVSC_RECEIVE_BUFFER_ID                0xcafe
 
-#define NETVSC_PACKET_SIZE                      2048
+#define NETVSC_PACKET_SIZE                      4096
 
 #define VRSS_SEND_TAB_SIZE 16
 
@@ -642,7 +642,7 @@ struct netvsc_device {
         int ring_size;
 
         /* The primary channel callback buffer */
-        unsigned char cb_buffer[NETVSC_PACKET_SIZE];
+        unsigned char *cb_buffer;
         /* The sub channel callback buffer */
         unsigned char *sub_cb_buf;
 };
diff --git a/drivers/net/hyperv/netvsc.c b/drivers/net/hyperv/netvsc.c
index 66979cf7fca6..5b5644a2233c 100644
--- a/drivers/net/hyperv/netvsc.c
+++ b/drivers/net/hyperv/netvsc.c
@@ -42,6 +42,12 @@ static struct netvsc_device *alloc_net_device(struct hv_device *device)
         if (!net_device)
                 return NULL;
 
+        net_device->cb_buffer = kzalloc(NETVSC_PACKET_SIZE, GFP_KERNEL);
+        if (!net_device->cb_buffer) {
+                kfree(net_device);
+                return NULL;
+        }
+
         init_waitqueue_head(&net_device->wait_drain);
         net_device->start_remove = false;
         net_device->destroy = false;
@@ -52,6 +58,12 @@ static struct netvsc_device *alloc_net_device(struct hv_device *device)
         return net_device;
 }
 
+static void free_netvsc_device(struct netvsc_device *nvdev)
+{
+        kfree(nvdev->cb_buffer);
+        kfree(nvdev);
+}
+
 static struct netvsc_device *get_outbound_net_device(struct hv_device *device)
 {
         struct netvsc_device *net_device;
@@ -551,7 +563,7 @@ int netvsc_device_remove(struct hv_device *device)
         if (net_device->sub_cb_buf)
                 vfree(net_device->sub_cb_buf);
 
-        kfree(net_device);
+        free_netvsc_device(net_device);
         return 0;
 }
 
@@ -1093,7 +1105,7 @@ close:
         vmbus_close(device->channel);
 
 cleanup:
-        kfree(net_device);
+        free_netvsc_device(net_device);
 
         return ret;
 }