Drivers: hv: kvp,vss: Fast propagation of userspace communication failure

[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 34f14fddb666bb753c92e3ea955264a862ef8976..9d5e0d1efdb51bd235f87bcdd914d2c5656d6d45 100644 (file)
--- a/drivers/hv/hv_snapshot.c
+++ b/drivers/hv/hv_snapshot.c
@@ -28,7 +28,7 @@
 #define VSS_MINOR  0
 #define VSS_VERSION    (VSS_MAJOR << 16 | VSS_MINOR)
 
-
+#define VSS_USERSPACE_TIMEOUT (msecs_to_jiffies(10 * 1000))
 
 /*
  * Global state maintained for transaction that is being processed.
@@ -55,12 +55,24 @@ static const char vss_name[] = "vss_kernel_module";
 static __u8 *recv_buffer;
 
 static void vss_send_op(struct work_struct *dummy);
+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);
 
 /*
  * Callback when data is received from user mode.
  */
 
+static void vss_timeout_func(struct work_struct *dummy)
+{
+       /*
+        * Timeout waiting for userspace component to reply happened.
+        */
+       pr_warn("VSS: timeout waiting for daemon to reply\n");
+       vss_respond_to_host(HV_E_FAIL);
+}
+
 static void
 vss_cn_callback(struct cn_msg *msg, struct netlink_skb_parms *nsp)
 {
@@ -76,13 +88,15 @@ vss_cn_callback(struct cn_msg *msg, struct netlink_skb_parms *nsp)
                return;
 
        }
-       vss_respond_to_host(vss_msg->error);
+       if (cancel_delayed_work_sync(&vss_timeout_work))
+               vss_respond_to_host(vss_msg->error);
 }
 
 
 static void vss_send_op(struct work_struct *dummy)
 {
        int op = vss_transaction.msg->vss_hdr.operation;
+       int rc;
        struct cn_msg *msg;
        struct hv_vss_msg *vss_msg;
 
@@ -98,7 +112,12 @@ static void vss_send_op(struct work_struct *dummy)
        vss_msg->vss_hdr.operation = op;
        msg->len = sizeof(struct hv_vss_msg);
 
-       cn_netlink_send(msg, 0, 0, GFP_ATOMIC);
+       rc = cn_netlink_send(msg, 0, 0, GFP_ATOMIC);
+       if (rc) {
+               pr_warn("VSS: failed to communicate to the daemon: %d\n", rc);
+               if (cancel_delayed_work_sync(&vss_timeout_work))
+                       vss_respond_to_host(HV_E_FAIL);
+       }
        kfree(msg);
 
        return;
@@ -223,6 +242,8 @@ void hv_vss_onchannelcallback(void *context)
                        case VSS_OP_FREEZE:
                        case VSS_OP_THAW:
                                schedule_work(&vss_send_op_work);
+                               schedule_delayed_work(&vss_timeout_work,
+                                                     VSS_USERSPACE_TIMEOUT);
                                return;
 
                        case VSS_OP_HOT_BACKUP:
@@ -277,5 +298,6 @@ hv_vss_init(struct hv_util_service *srv)
 void hv_vss_deinit(void)
 {
        cn_del_callback(&vss_id);
+       cancel_delayed_work_sync(&vss_timeout_work);
        cancel_work_sync(&vss_send_op_work);
 }