Drivers: hv: fcopy: full handshake support

[firefly-linux-kernel-4.4.55.git] / drivers / hv / hv_fcopy.c

diff --git a/drivers/hv/hv_fcopy.c b/drivers/hv/hv_fcopy.c
index 6a8ec9fb0869c14b764b9856f8edbe683d2cd188..b7b528cd481b02c3eea29803836730dac3369447 100644 (file)
--- a/drivers/hv/hv_fcopy.c
+++ b/drivers/hv/hv_fcopy.c
@@ -62,6 +62,10 @@ static DECLARE_WORK(fcopy_send_work, fcopy_send_data);
 static const char fcopy_devname[] = "vmbus/hv_fcopy";
 static u8 *recv_buffer;
 static struct hvutil_transport *hvt;
+/*
+ * This state maintains the version number registered by the daemon.
+ */
+static int dm_reg_value;
 
 static void fcopy_timeout_func(struct work_struct *dummy)
 {
@@ -81,8 +85,18 @@ static void fcopy_timeout_func(struct work_struct *dummy)
 
 static int fcopy_handle_handshake(u32 version)
 {
+       u32 our_ver = FCOPY_CURRENT_VERSION;
+
        switch (version) {
-       case FCOPY_CURRENT_VERSION:
+       case FCOPY_VERSION_0:
+               /* Daemon doesn't expect us to reply */
+               dm_reg_value = version;
+               break;
+       case FCOPY_VERSION_1:
+               /* Daemon expects us to reply with our own version */
+               if (hvutil_transport_send(hvt, &our_ver, sizeof(our_ver)))
+                       return -EFAULT;
+               dm_reg_value = version;
                break;
        default:
                /*