[PATCH 6/7] Drivers: hv: vmbus: Suspend/resume the vmbus itself for hibernation

[Dexuan Cui]

This is needed when we resume the old kernel from the "current" kernel.

Signed-off-by: Dexuan Cui <de...@microsoft.com>
---
 drivers/hv/connection.c   |  3 +--
 drivers/hv/hyperv_vmbus.h |  2 ++
 drivers/hv/vmbus_drv.c    | 40 ++++++++++++++++++++++++++++++++++++++++
 3 files changed, 43 insertions(+), 2 deletions(-)

diff --git a/drivers/hv/connection.c b/drivers/hv/connection.c
index 09829e1..806319c 100644
--- a/drivers/hv/connection.c
+++ b/drivers/hv/connection.c
@@ -59,8 +59,7 @@ static __u32 vmbus_get_next_version(__u32 current_version)
        }
 }
 
-static int vmbus_negotiate_version(struct vmbus_channel_msginfo *msginfo,
-                                       __u32 version)
+int vmbus_negotiate_version(struct vmbus_channel_msginfo *msginfo, u32 version)
 {
        int ret = 0;
        unsigned int cur_cpu;
diff --git a/drivers/hv/hyperv_vmbus.h b/drivers/hv/hyperv_vmbus.h
index 26ea161..e657197 100644
--- a/drivers/hv/hyperv_vmbus.h
+++ b/drivers/hv/hyperv_vmbus.h
@@ -274,6 +274,8 @@ struct vmbus_msginfo {
 
 extern struct vmbus_connection vmbus_connection;
 
+int vmbus_negotiate_version(struct vmbus_channel_msginfo *msginfo, u32 
version);
+
 static inline void vmbus_send_interrupt(u32 relid)
 {
        sync_set_bit(relid, vmbus_connection.send_int_page);
diff --git a/drivers/hv/vmbus_drv.c b/drivers/hv/vmbus_drv.c
index 1c2d935..1730e7b 100644
--- a/drivers/hv/vmbus_drv.c
+++ b/drivers/hv/vmbus_drv.c
@@ -2045,6 +2045,41 @@ static int vmbus_acpi_add(struct acpi_device *device)
        return ret_val;
 }
 
+static int vmbus_bus_suspend(struct device *dev)
+{
+       vmbus_initiate_unload(false);
+
+       vmbus_connection.conn_state = DISCONNECTED;
+
+       return 0;
+}
+
+static int vmbus_bus_resume(struct device *dev)
+{
+       struct vmbus_channel_msginfo *msginfo;
+       size_t msgsize;
+       int ret;
+
+       msgsize = sizeof(*msginfo) +
+                 sizeof(struct vmbus_channel_initiate_contact);
+
+       msginfo = kzalloc(msgsize, GFP_KERNEL);
+
+       if (msginfo == NULL)
+               return -ENOMEM;
+
+       ret = vmbus_negotiate_version(msginfo, vmbus_proto_version);
+
+       kfree(msginfo);
+
+       if (ret != 0)
+               return ret;
+
+       vmbus_request_offers();
+
+       return 0;
+}
+
 static const struct acpi_device_id vmbus_acpi_device_ids[] = {
        {"VMBUS", 0},
        {"VMBus", 0},
@@ -2052,6 +2087,10 @@ static int vmbus_acpi_add(struct acpi_device *device)
 };
 MODULE_DEVICE_TABLE(acpi, vmbus_acpi_device_ids);
 
+static const struct dev_pm_ops vmbus_bus_pm = {
+       SET_SYSTEM_SLEEP_PM_OPS(vmbus_bus_suspend, vmbus_bus_resume)
+};
+
 static struct acpi_driver vmbus_acpi_driver = {
        .name = "vmbus",
        .ids = vmbus_acpi_device_ids,
@@ -2059,6 +2098,7 @@ static int vmbus_acpi_add(struct acpi_device *device)
                .add = vmbus_acpi_add,
                .remove = vmbus_acpi_remove,
        },
+       .drv.pm = &vmbus_bus_pm,
 };
 
 static void hv_kexec_handler(void)
-- 
1.8.3.1