[PATCH v6 04/15] staging: gpib: cb7210: Handle gpib_register_driver() errors

[Nihar Chaithanya <niharchaithanya@xxxxxxxxx>]

The function cb_pcmcia_init_module() can be replaced by calling
pcmcia_register_driver() directly. The error value from this
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.

Replace cb_pcmcia_init_module() with pcmcia_register_driver().
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 to indicate the fail and also the error
value.

Signed-off-by: Nihar Chaithanya <niharchaithanya@xxxxxxxxx>
---
 drivers/staging/gpib/cb7210/cb7210.c | 116 +++++++++++++++++++++------
 1 file changed, 90 insertions(+), 26 deletions(-)

diff --git a/drivers/staging/gpib/cb7210/cb7210.c b/drivers/staging/gpib/cb7210/cb7210.c
index 63df7f3eb3f3..45a54219ea6d 100644
--- a/drivers/staging/gpib/cb7210/cb7210.c
+++ b/drivers/staging/gpib/cb7210/cb7210.c
@@ -1351,12 +1351,6 @@ static struct pcmcia_driver cb_gpib_cs_driver = {
 	.resume		= cb_gpib_resume,
 };
 
-int cb_pcmcia_init_module(void)
-{
-	pcmcia_register_driver(&cb_gpib_cs_driver);
-	return 0;
-}
-
 void cb_pcmcia_cleanup_module(void)
 {
 	DEBUG(0, "cb_gpib_cs: unloading\n");
@@ -1506,32 +1500,102 @@ void cb_pcmcia_detach(gpib_board_t *board)
 
 static int __init cb7210_init_module(void)
 {
-	int err = 0;
-	int result;
+	int ret;
+
+	ret = pci_register_driver(&cb7210_pci_driver);
+	if (ret) {
+		pr_err("cb7210: pci_register_driver failed: error = %d\n", ret);
+		return ret;
+	}
+
+	ret = gpib_register_driver(&cb_pci_interface, THIS_MODULE);
+	if (ret) {
+		pr_err("cb7210: gpib_register_driver failed: error = %d\n", ret);
+		goto err_pci;
+	}
+
+	ret = gpib_register_driver(&cb_isa_interface, THIS_MODULE);
+	if (ret) {
+		pr_err("cb7210: gpib_register_driver failed: error = %d\n", ret);
+		goto err_isa;
+	}
 
-	result = pci_register_driver(&cb7210_pci_driver);
-	if (result) {
-		pr_err("cb7210: pci_driver_register failed!\n");
-		return result;
+	ret = gpib_register_driver(&cb_pci_accel_interface, THIS_MODULE);
+	if (ret) {
+		pr_err("cb7210: gpib_register_driver failed: error = %d\n", ret);
+		goto err_pci_accel;
 	}
 
-	gpib_register_driver(&cb_pci_interface, THIS_MODULE);
-	gpib_register_driver(&cb_isa_interface, THIS_MODULE);
-	gpib_register_driver(&cb_pci_accel_interface, THIS_MODULE);
-	gpib_register_driver(&cb_pci_unaccel_interface, THIS_MODULE);
-	gpib_register_driver(&cb_isa_accel_interface, THIS_MODULE);
-	gpib_register_driver(&cb_isa_unaccel_interface, THIS_MODULE);
-
-#ifdef GPIB__PCMCIA
-	gpib_register_driver(&cb_pcmcia_interface, THIS_MODULE);
-	gpib_register_driver(&cb_pcmcia_accel_interface, THIS_MODULE);
-	gpib_register_driver(&cb_pcmcia_unaccel_interface, THIS_MODULE);
-	err += cb_pcmcia_init_module();
+	ret = gpib_register_driver(&cb_pci_unaccel_interface, THIS_MODULE);
+	if (ret) {
+		pr_err("cb7210: gpib_register_driver failed: error = %d\n", ret);
+		goto err_pci_unaccel;
+	}
+
+	ret = gpib_register_driver(&cb_isa_accel_interface, THIS_MODULE);
+	if (ret) {
+		pr_err("cb7210: gpib_register_driver failed: error = %d\n", ret);
+		goto err_isa_accel;
+	}
+
+	ret = gpib_register_driver(&cb_isa_unaccel_interface, THIS_MODULE);
+	if (ret) {
+		pr_err("cb7210: gpib_register_driver failed: error = %d\n", ret);
+		goto err_isa_unaccel;
+	}
+
+#ifdef GPIB_PCMCIA
+	ret = gpib_register_driver(&cb_pcmcia_interface, THIS_MODULE);
+	if (ret) {
+		pr_err("cb7210: gpib_register_driver failed: error = %d\n", ret);
+		goto err_pcmcia;
+	}
+
+	ret = gpib_register_driver(&cb_pcmcia_accel_interface, THIS_MODULE);
+	if (ret) {
+		pr_err("cb7210: gpib_register_driver failed: error = %d\n", ret);
+		goto err_pcmcia_accel;
+	}
+
+	ret = gpib_register_driver(&cb_pcmcia_unaccel_interface, THIS_MODULE);
+	if (ret) {
+		pr_err("cb7210: gpib_register_driver failed: error = %d\n", ret);
+		goto err_pcmcia_unaccel;
+	}
+
+	ret = pcmcia_register_driver(&cb_gpib_cs_driver);
+	if (ret) {
+		pr_err("cb7210: pcmcia_register_driver failed: error = %d\n", ret);
+		goto err_pcmcia_driver;
+	}
 #endif
-	if (err)
-		return -1;
 
 	return 0;
+
+#ifdef GPIB_PCMCIA
+err_pcmcia_driver:
+	gpib_unregister_driver(&cb_pcmcia_unaccel_interface);
+err_pcmcia_unaccel:
+	gpib_unregister_driver(&cb_pcmcia_accel_interface);
+err_pcmcia_accel:
+	gpib_unregister_driver(&cb_pcmcia_interface);
+err_pcmcia:
+#endif
+	gpib_unregister_driver(&cb_isa_unaccel_interface);
+err_isa_unaccel:
+	gpib_unregister_driver(&cb_isa_accel_interface);
+err_isa_accel:
+	gpib_unregister_driver(&cb_pci_unaccel_interface);
+err_pci_unaccel:
+	gpib_unregister_driver(&cb_pci_accel_interface);
+err_pci_accel:
+	gpib_unregister_driver(&cb_isa_interface);
+err_isa:
+	gpib_unregister_driver(&cb_pci_interface);
+err_pci:
+	pci_unregister_driver(&cb7210_pci_driver);
+
+	return ret;
 }
 
 static void __exit cb7210_exit_module(void)
-- 
2.34.1