[SCSI] zfcp: Fix oops during shutdown of offline device

With the change that the zfcp_adapter struct is only allocated when
the device is set online, the shutdown handler has to check for a
non-existing zfcp_adapter struct. On the other hand, this check is not
necessary in the offline callback, since an online device has the
zfcp_adapter allocated and we go through the offline callback before
removing the ccw device.

Reviewed-by: Felix Beck <felix.beck@de.ibm.com>
Signed-off-by: Christof Schmitt <christof.schmitt@de.ibm.com>
Signed-off-by: James Bottomley <James.Bottomley@suse.de>

drivers/s390/scsi/zfcp_ccw.c

@@ -192,13 +192,9 @@ static int zfcp_ccw_set_offline(struct ccw_device *ccw_device)
 
 	mutex_lock(&zfcp_data.config_mutex);
 	adapter = dev_get_drvdata(&ccw_device->dev);
-	if (!adapter)
-		goto out;
-
 	zfcp_erp_adapter_shutdown(adapter, 0, "ccsoff1", NULL);
 	zfcp_erp_wait(adapter);
 	mutex_unlock(&zfcp_data.config_mutex);
-out:
 	return 0;
 }
 
@@ -253,9 +249,13 @@ static void zfcp_ccw_shutdown(struct ccw_device *cdev)
 
 	mutex_lock(&zfcp_data.config_mutex);
 	adapter = dev_get_drvdata(&cdev->dev);
+	if (!adapter)
+		goto out;
+
 	zfcp_erp_adapter_shutdown(adapter, 0, "ccshut1", NULL);
 	zfcp_erp_wait(adapter);
 	zfcp_erp_thread_kill(adapter);
+out:
 	mutex_unlock(&zfcp_data.config_mutex);
 }