[SCSI] SCSI megaraid_sas: handle thrown errors

- handle clear_user() error

- handle and properly unwind from sysfs errors thrown during mod init

- adjust order of calls in megasas_exit() to precisely match
  registration order in megasas_init()

Signed-off-by: Jeff Garzik <jeff@garzik.org>

Updated for extra attribute and
Signed-off-by: James Bottomley <James.Bottomley@SteelEye.com>

drivers/scsi/megaraid/megaraid_sas.c

@@ -2864,7 +2864,8 @@ static int megasas_mgmt_compat_ioctl_fw(struct file *file, unsigned long arg)
 	int i;
 	int error = 0;
 
-	clear_user(ioc, sizeof(*ioc));
+	if (clear_user(ioc, sizeof(*ioc)))
+		return -EFAULT;
 
 	if (copy_in_user(&ioc->host_no, &cioc->host_no, sizeof(u16)) ||
 	    copy_in_user(&ioc->sgl_off, &cioc->sgl_off, sizeof(u32)) ||
@@ -3010,28 +3011,45 @@ static int __init megasas_init(void)
 
 	if (rval) {
 		printk(KERN_DEBUG "megasas: PCI hotplug regisration failed \n");
-		unregister_chrdev(megasas_mgmt_majorno, "megaraid_sas_ioctl");
-	}
-
-	driver_create_file(&megasas_pci_driver.driver, &driver_attr_version);
-	driver_create_file(&megasas_pci_driver.driver,
-			   &driver_attr_release_date);
-	driver_create_file(&megasas_pci_driver.driver,
-			   &driver_attr_dbg_lvl);
+		goto err_pcidrv;
+	}
+
+	rval = driver_create_file(&megasas_pci_driver.driver,
+				  &driver_attr_version);
+	if (rval)
+		goto err_dcf_attr_ver;
+	rval = driver_create_file(&megasas_pci_driver.driver,
+				  &driver_attr_release_date);
+	if (rval)
+		goto err_dcf_rel_date;
+	rval = driver_create_file(&megasas_pci_driver.driver,
+				  &driver_attr_dbg_lvl);
+	if (rval)
+		goto err_dcf_dbg_lvl;
 
 	return rval;
+err_dcf_dbg_lvl:
+	driver_remove_file(&megasas_pci_driver.driver,
+			   &driver_attr_release_date);
+err_dcf_rel_date:
+	driver_remove_file(&megasas_pci_driver.driver, &driver_attr_version);
+err_dcf_attr_ver:
+	pci_unregister_driver(&megasas_pci_driver);
+err_pcidrv:
+	unregister_chrdev(megasas_mgmt_majorno, "megaraid_sas_ioctl");
+  	return rval;
 }
 
 /**
  * megasas_exit - Driver unload entry point
  */
 static void __exit megasas_exit(void)
 {
-	driver_remove_file(&megasas_pci_driver.driver, &driver_attr_version);
-	driver_remove_file(&megasas_pci_driver.driver,
-			   &driver_attr_release_date);
 	driver_remove_file(&megasas_pci_driver.driver,
 			   &driver_attr_dbg_lvl);
+	driver_remove_file(&megasas_pci_driver.driver,
+			   &driver_attr_release_date);
+	driver_remove_file(&megasas_pci_driver.driver, &driver_attr_version);
 
 	pci_unregister_driver(&megasas_pci_driver);
 	unregister_chrdev(megasas_mgmt_majorno, "megaraid_sas_ioctl");