Upgrade to 4.4.50-rt62

[kvmfornfv.git] / kernel / drivers / hv / hv_snapshot.c

diff --git a/kernel/drivers/hv/hv_snapshot.c b/kernel/drivers/hv/hv_snapshot.c
index 815405f..81882d4 100644 (file)
--- a/kernel/drivers/hv/hv_snapshot.c
+++ b/kernel/drivers/hv/hv_snapshot.c
@@ -53,7 +53,6 @@ static struct {
        struct vmbus_channel *recv_channel; /* chn we got the request */
        u64 recv_req_id; /* request ID. */
        struct hv_vss_msg  *msg; /* current message */
-       void *vss_context; /* for the channel callback */
 } vss_transaction;
 
 
@@ -74,6 +73,13 @@ static void vss_timeout_func(struct work_struct *dummy);
 static DECLARE_DELAYED_WORK(vss_timeout_work, vss_timeout_func);
 static DECLARE_WORK(vss_send_op_work, vss_send_op);
 
+static void vss_poll_wrapper(void *channel)
+{
+       /* Transaction is finished, reset the state here to avoid races. */
+       vss_transaction.state = HVUTIL_READY;
+       hv_vss_onchannelcallback(channel);
+}
+
 /*
  * Callback when data is received from user mode.
  */
@@ -86,12 +92,7 @@ static void vss_timeout_func(struct work_struct *dummy)
        pr_warn("VSS: timeout waiting for daemon to reply\n");
        vss_respond_to_host(HV_E_FAIL);
 
-       /* Transaction is finished, reset the state. */
-       if (vss_transaction.state > HVUTIL_READY)
-               vss_transaction.state = HVUTIL_READY;
-
-       hv_poll_channel(vss_transaction.vss_context,
-                       hv_vss_onchannelcallback);
+       hv_poll_channel(vss_transaction.recv_channel, vss_poll_wrapper);
 }
 
 static int vss_handle_handshake(struct hv_vss_msg *vss_msg)
@@ -138,9 +139,8 @@ static int vss_on_msg(void *msg, int len)
                if (cancel_delayed_work_sync(&vss_timeout_work)) {
                        vss_respond_to_host(vss_msg->error);
                        /* Transaction is finished, reset the state. */
-                       vss_transaction.state = HVUTIL_READY;
-                       hv_poll_channel(vss_transaction.vss_context,
-                                       hv_vss_onchannelcallback);
+                       hv_poll_channel(vss_transaction.recv_channel,
+                                       vss_poll_wrapper);
                }
        } else {
                /* This is a spurious call! */
@@ -238,15 +238,8 @@ void hv_vss_onchannelcallback(void *context)
        struct icmsg_hdr *icmsghdrp;
        struct icmsg_negotiate *negop = NULL;
 
-       if (vss_transaction.state > HVUTIL_READY) {
-               /*
-                * We will defer processing this callback once
-                * the current transaction is complete.
-                */
-               vss_transaction.vss_context = context;
+       if (vss_transaction.state > HVUTIL_READY)
                return;
-       }
-       vss_transaction.vss_context = NULL;
 
        vmbus_recvpacket(channel, recv_buffer, PAGE_SIZE * 2, &recvlen,
                         &requestid);
@@ -338,6 +331,11 @@ static void vss_on_reset(void)
 int
 hv_vss_init(struct hv_util_service *srv)
 {
+       if (vmbus_proto_version < VERSION_WIN8_1) {
+               pr_warn("Integration service 'Backup (volume snapshot)'"
+                       " not supported on this host version.\n");
+               return -ENOTSUPP;
+       }
        recv_buffer = srv->recv_buffer;
 
        /*