Merge tag 'topic/drm-fixes-2015-07-16' of git://anongit.freedesktop.org/drm-intel...

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

diff --git a/drivers/hv/hv_snapshot.c b/drivers/hv/hv_snapshot.c
index 2c8c246d09eb7371d0c8711d6f4cf0b033dc00ef..815405f2e777daba30f0db91216ca04a56b81a6a 100644 (file)
--- a/drivers/hv/hv_snapshot.c
+++ b/drivers/hv/hv_snapshot.c
@@ -59,6 +59,11 @@ static struct {
 
 static void vss_respond_to_host(int error);
 
+/*
+ * This state maintains the version number registered by the daemon.
+ */
+static int dm_reg_value;
+
 static const char vss_devname[] = "vmbus/hv_vss";
 static __u8 *recv_buffer;
 static struct hvutil_transport *hvt;
@@ -89,6 +94,29 @@ static void vss_timeout_func(struct work_struct *dummy)
                        hv_vss_onchannelcallback);
 }
 
+static int vss_handle_handshake(struct hv_vss_msg *vss_msg)
+{
+       u32 our_ver = VSS_OP_REGISTER1;
+
+       switch (vss_msg->vss_hdr.operation) {
+       case VSS_OP_REGISTER:
+               /* Daemon doesn't expect us to reply */
+               dm_reg_value = VSS_OP_REGISTER;
+               break;
+       case VSS_OP_REGISTER1:
+               /* Daemon expects us to reply with our own version*/
+               if (hvutil_transport_send(hvt, &our_ver, sizeof(our_ver)))
+                       return -EFAULT;
+               dm_reg_value = VSS_OP_REGISTER1;
+               break;
+       default:
+               return -EINVAL;
+       }
+       vss_transaction.state = HVUTIL_READY;
+       pr_debug("VSS: userspace daemon ver. %d registered\n", dm_reg_value);
+       return 0;
+}
+
 static int vss_on_msg(void *msg, int len)
 {
        struct hv_vss_msg *vss_msg = (struct hv_vss_msg *)msg;
@@ -96,18 +124,15 @@ static int vss_on_msg(void *msg, int len)
        if (len != sizeof(*vss_msg))
                return -EINVAL;
 
-       /*
-        * Don't process registration messages if we're in the middle of
-        * a transaction processing.
-        */
-       if (vss_transaction.state > HVUTIL_READY &&
-           vss_msg->vss_hdr.operation == VSS_OP_REGISTER)
-               return -EINVAL;
-
-       if (vss_transaction.state == HVUTIL_DEVICE_INIT &&
-           vss_msg->vss_hdr.operation == VSS_OP_REGISTER) {
-               pr_info("VSS daemon registered\n");
-               vss_transaction.state = HVUTIL_READY;
+       if (vss_msg->vss_hdr.operation == VSS_OP_REGISTER ||
+           vss_msg->vss_hdr.operation == VSS_OP_REGISTER1) {
+               /*
+                * Don't process registration messages if we're in the middle
+                * of a transaction processing.
+                */
+               if (vss_transaction.state > HVUTIL_READY)
+                       return -EINVAL;
+               return vss_handle_handshake(vss_msg);
        } else if (vss_transaction.state == HVUTIL_USERSPACE_REQ) {
                vss_transaction.state = HVUTIL_USERSPACE_RECV;
                if (cancel_delayed_work_sync(&vss_timeout_work)) {