staging: gpib: tnt4882: Handle gpib_register_driver() errors

The error value from the init_ni_gpib_cs() function is not
returned and the previous registering functions are not unregistered.

The function gpib_register_driver() can fail and similar to
pcmcia_register_driver() function failing, the previous registering
functions are not unregistered.

Unregister the gpib and pci register functions if the subsequent
gpib or pcmcia register functions fail and return the error value. Add
pr_err() statements indicating the fail and the error value.

Signed-off-by: Nihar Chaithanya <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Greg Kroah-Hartman <[email protected]>

Author: niharcy

drivers/staging/gpib/tnt4882/tnt4882_gpib.c

@@ -1524,29 +1524,109 @@ static int __init tnt4882_init_module(void)
 
 	result = pci_register_driver(&tnt4882_pci_driver);
 	if (result) {
-		pr_err("tnt4882: pci_driver_register failed!\n");
+		pr_err("tnt4882_gpib: pci_register_driver failed: error = %d\n", result);
 		return result;
 	}
 
-	gpib_register_driver(&ni_isa_interface, THIS_MODULE);
-	gpib_register_driver(&ni_isa_accel_interface, THIS_MODULE);
-	gpib_register_driver(&ni_nat4882_isa_interface, THIS_MODULE);
-	gpib_register_driver(&ni_nat4882_isa_accel_interface, THIS_MODULE);
-	gpib_register_driver(&ni_nec_isa_interface, THIS_MODULE);
-	gpib_register_driver(&ni_nec_isa_accel_interface, THIS_MODULE);
-	gpib_register_driver(&ni_pci_interface, THIS_MODULE);
-	gpib_register_driver(&ni_pci_accel_interface, THIS_MODULE);
+	result = gpib_register_driver(&ni_isa_interface, THIS_MODULE);
+	if (result) {
+		pr_err("tnt4882_gpib: gpib_register_driver failed: error = %d\n", result);
+		goto err_isa;
+	}
+
+	result = gpib_register_driver(&ni_isa_accel_interface, THIS_MODULE);
+	if (result) {
+		pr_err("tnt4882_gpib: gpib_register_driver failed: error = %d\n", result);
+		goto err_isa_accel;
+	}
+
+	result = gpib_register_driver(&ni_nat4882_isa_interface, THIS_MODULE);
+	if (result) {
+		pr_err("tnt4882_gpib: gpib_register_driver failed: error = %d\n", result);
+		goto err_nat4882_isa;
+	}
+
+	result = gpib_register_driver(&ni_nat4882_isa_accel_interface, THIS_MODULE);
+	if (result) {
+		pr_err("tnt4882_gpib: gpib_register_driver failed: error = %d\n", result);
+		goto err_nat4882_isa_accel;
+	}
+
+	result = gpib_register_driver(&ni_nec_isa_interface, THIS_MODULE);
+	if (result) {
+		pr_err("tnt4882_gpib: gpib_register_driver failed: error = %d\n", result);
+		goto err_nec_isa;
+	}
+
+	result = gpib_register_driver(&ni_nec_isa_accel_interface, THIS_MODULE);
+	if (result) {
+		pr_err("tnt4882_gpib: gpib_register_driver failed: error = %d\n", result);
+		goto err_nec_isa_accel;
+	}
+
+	result = gpib_register_driver(&ni_pci_interface, THIS_MODULE);
+	if (result) {
+		pr_err("tnt4882_gpib: gpib_register_driver failed: error = %d\n", result);
+		goto err_pci;
+	}
+
+	result = gpib_register_driver(&ni_pci_accel_interface, THIS_MODULE);
+	if (result) {
+		pr_err("tnt4882_gpib: gpib_register_driver failed: error = %d\n", result);
+		goto err_pci_accel;
+	}
+
 #ifdef GPIB_PCMCIA
-	gpib_register_driver(&ni_pcmcia_interface, THIS_MODULE);
-	gpib_register_driver(&ni_pcmcia_accel_interface, THIS_MODULE);
-	if (init_ni_gpib_cs() < 0)
-		return -1;
+	result = gpib_register_driver(&ni_pcmcia_interface, THIS_MODULE);
+	if (result) {
+		pr_err("tnt4882_gpib: gpib_register_driver failed: error = %d\n", result);
+		goto err_pcmcia;
+	}
+
+	result = gpib_register_driver(&ni_pcmcia_accel_interface, THIS_MODULE);
+	if (result) {
+		pr_err("tnt4882_gpib: gpib_register_driver failed: error = %d\n", result);
+		goto err_pcmcia_accel;
+	}
+
+	result = init_ni_gpib_cs();
+	if (result) {
+		pr_err("tnt4882_gpib: pcmcia_register_driver failed: error = %d\n", result);
+		goto err_pcmcia_driver;
+	}
 #endif
 
 	mite_init();
 	mite_list_devices();
 
 	return 0;
+
+#ifdef GPIB_PCMCIA
+err_pcmcia_driver:
+	gpib_unregister_driver(&ni_pcmcia_accel_interface);
+err_pcmcia_accel:
+	gpib_unregister_driver(&ni_pcmcia_interface);
+err_pcmcia:
+#endif
+	gpib_unregister_driver(&ni_pci_accel_interface);
+err_pci_accel:
+	gpib_unregister_driver(&ni_pci_interface);
+err_pci:
+	gpib_unregister_driver(&ni_nec_isa_accel_interface);
+err_nec_isa_accel:
+	gpib_unregister_driver(&ni_nec_isa_interface);
+err_nec_isa:
+	gpib_unregister_driver(&ni_nat4882_isa_accel_interface);
+err_nat4882_isa_accel:
+	gpib_unregister_driver(&ni_nat4882_isa_interface);
+err_nat4882_isa:
+	gpib_unregister_driver(&ni_isa_accel_interface);
+err_isa_accel:
+	gpib_unregister_driver(&ni_isa_interface);
+err_isa:
+	pci_unregister_driver(&tnt4882_pci_driver);
+
+	return result;
 }
 
 static void __exit tnt4882_exit_module(void)