mei: bus: prevent hardware module unload if device on bus is active

The hardware module should not be unloaded if the bus
has active devices.
Get get_/put_ bus parent module upon client device
connection/disconnection, to prevent the hardware managing
module to disappear underneath.

Signed-off-by: Alexander Usyskin <alexander.usyskin@intel.com>
Signed-off-by: Tomas Winkler <tomas.winkler@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/misc/mei/bus.c b/drivers/misc/mei/bus.c
index 3bb1f1500f6be3b76b2c70e1a7a76c74c07e2131..b67f15b5306749cf18656078fa3727672652a2d9 100644 (file)
--- a/drivers/misc/mei/bus.c
+++ b/drivers/misc/mei/bus.c
@@ -541,6 +541,37 @@ out:
 }
 EXPORT_SYMBOL_GPL(mei_cldev_disable);
 
+/**
+ * mei_cl_bus_module_get - acquire module of the underlying
+ *    hw module.
+ *
+ * @cl: host client
+ *
+ * Return: true on success; false if the module was removed.
+ */
+bool mei_cl_bus_module_get(struct mei_cl *cl)
+{
+       struct mei_cl_device *cldev = cl->cldev;
+
+       if (!cldev)
+               return true;
+
+       return try_module_get(cldev->bus->dev->driver->owner);
+}
+
+/**
+ * mei_cl_bus_module_put -  release the underlying hw module.
+ *
+ * @cl: host client
+ */
+void mei_cl_bus_module_put(struct mei_cl *cl)
+{
+       struct mei_cl_device *cldev = cl->cldev;
+
+       if (cldev)
+               module_put(cldev->bus->dev->driver->owner);
+}
+
 /**
  * mei_cl_device_find - find matching entry in the driver id table
  *

diff --git a/drivers/misc/mei/client.c b/drivers/misc/mei/client.c
index da1c0703910a4d1d7def39156df2f73ef30b0902..619b4702347f8a528a28e4040bb26d1dfde43a2b 100644 (file)
--- a/drivers/misc/mei/client.c
+++ b/drivers/misc/mei/client.c
@@ -774,6 +774,8 @@ static void mei_cl_set_disconnected(struct mei_cl *cl)
        cl->tx_flow_ctrl_creds = 0;
        cl->timer_count = 0;
 
+       mei_cl_bus_module_put(cl);
+
        if (!cl->me_cl)
                return;
 
@@ -1077,13 +1079,17 @@ int mei_cl_connect(struct mei_cl *cl, struct mei_me_client *me_cl,
 
        dev = cl->dev;
 
+       if (!mei_cl_bus_module_get(cl))
+               return -ENODEV;
+
        rets = mei_cl_set_connecting(cl, me_cl);
        if (rets)
-               return rets;
+               goto nortpm;
 
        if (mei_cl_is_fixed_address(cl)) {
                cl->state = MEI_FILE_CONNECTED;
-               return 0;
+               rets = 0;
+               goto nortpm;
        }
 
        rets = pm_runtime_get(dev->dev);

diff --git a/drivers/misc/mei/mei_dev.h b/drivers/misc/mei/mei_dev.h
index 8dadb98662a9e61da14ed8d95268bc9b4ec23d2b..33ff4b7e356d6d9c833a82d62e88c9b854665b81 100644 (file)
--- a/drivers/misc/mei/mei_dev.h
+++ b/drivers/misc/mei/mei_dev.h
@@ -328,6 +328,8 @@ ssize_t __mei_cl_recv(struct mei_cl *cl, u8 *buf, size_t length,
 bool mei_cl_bus_rx_event(struct mei_cl *cl);
 bool mei_cl_bus_notify_event(struct mei_cl *cl);
 void mei_cl_bus_remove_devices(struct mei_device *bus);
+bool mei_cl_bus_module_get(struct mei_cl *cl);
+void mei_cl_bus_module_put(struct mei_cl *cl);
 int mei_cl_bus_init(void);
 void mei_cl_bus_exit(void);