Drivers: hv: util: Backup: Fix a rescind processing issue

commit d77044d142e960f7b5f814a91ecb8bcf86aa552c upstream.

VSS may use a char device to support the communication between
the user level daemon and the driver. When the VSS channel is rescinded
we need to make sure that the char device is fully cleaned up before
we can process a new VSS offer from the host. Implement this logic.

Signed-off-by: K. Y. Srinivasan <kys@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/hv/hv_snapshot.c b/drivers/hv/hv_snapshot.c
index 81882d4848bdf1f29f1d26e86bd27f49b3ddb206..faad79ae318a63bf87ab6a3a190565fb3af96ec6 100644 (file)
--- a/drivers/hv/hv_snapshot.c
+++ b/drivers/hv/hv_snapshot.c
@@ -66,6 +66,7 @@ static int dm_reg_value;
 static const char vss_devname[] = "vmbus/hv_vss";
 static __u8 *recv_buffer;
 static struct hvutil_transport *hvt;
+static struct completion release_event;
 
 static void vss_send_op(struct work_struct *dummy);
 static void vss_timeout_func(struct work_struct *dummy);
@@ -326,11 +327,13 @@ static void vss_on_reset(void)
        if (cancel_delayed_work_sync(&vss_timeout_work))
                vss_respond_to_host(HV_E_FAIL);
        vss_transaction.state = HVUTIL_DEVICE_INIT;
+       complete(&release_event);
 }
 
 int
 hv_vss_init(struct hv_util_service *srv)
 {
+       init_completion(&release_event);
        if (vmbus_proto_version < VERSION_WIN8_1) {
                pr_warn("Integration service 'Backup (volume snapshot)'"
                        " not supported on this host version.\n");
@@ -360,4 +363,5 @@ void hv_vss_deinit(void)
        cancel_delayed_work_sync(&vss_timeout_work);
        cancel_work_sync(&vss_send_op_work);
        hvutil_transport_destroy(hvt);
+       wait_for_completion(&release_event);
 }