[PATCH] efi: fix failure handling

The EFI driver allocates memory and writes into it without checking the
success of the allocation.  Furthermore, on failure of the
firmware_register() it doesn't free the allocated memory and on failure of
the subsys_create_file() calls it returns zero instead of the errorcode.
Signed-off-by: Panagiotis Issaris <panagiotis.issaris@mech.kuleuven.ac.be>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

drivers/firmware/efivars.c

@@ -665,14 +665,22 @@ efivars_init(void)
 {
 	efi_status_t status = EFI_NOT_FOUND;
 	efi_guid_t vendor_guid;
-	efi_char16_t *variable_name = kmalloc(1024, GFP_KERNEL);
+	efi_char16_t *variable_name;
 	struct subsys_attribute *attr;
 	unsigned long variable_name_size = 1024;
-	int i, rc = 0, error = 0;
+	int i, error = 0;
 
 	if (!efi_enabled)
 		return -ENODEV;
 
+	variable_name = kmalloc(variable_name_size, GFP_KERNEL);
+	if (!variable_name) {
+		printk(KERN_ERR "efivars: Memory allocation failed.\n");
+		return -ENOMEM;
+	}
+
+	memset(variable_name, 0, variable_name_size);
+
 	printk(KERN_INFO "EFI Variables Facility v%s %s\n", EFIVARS_VERSION,
 	       EFIVARS_DATE);
 
@@ -680,21 +688,27 @@ efivars_init(void)
 	 * For now we'll register the efi subsys within this driver
 	 */
 
-	rc = firmware_register(&efi_subsys);
+	error = firmware_register(&efi_subsys);
 
-	if (rc)
-		return rc;
+	if (error) {
+		printk(KERN_ERR "efivars: Firmware registration failed with error %d.\n", error);
+		goto out_free;
+	}
 
 	kset_set_kset_s(&vars_subsys, efi_subsys);
-	subsystem_register(&vars_subsys);
+
+	error = subsystem_register(&vars_subsys);
+
+	if (error) {
+		printk(KERN_ERR "efivars: Subsystem registration failed with error %d.\n", error);
+		goto out_firmware_unregister;
+	}
 
 	/*
 	 * Per EFI spec, the maximum storage allocated for both
 	 * the variable name and variable data is 1024 bytes.
 	 */
 
-	memset(variable_name, 0, 1024);
-
 	do {
 		variable_name_size = 1024;
 
@@ -734,8 +748,20 @@ efivars_init(void)
 			error = subsys_create_file(&efi_subsys, attr);
 	}
 
+	if (error)
+		printk(KERN_ERR "efivars: Sysfs attribute export failed with error %d.\n", error);
+	else
+		goto out_free;
+
+	subsystem_unregister(&vars_subsys);
+
+out_firmware_unregister:
+	firmware_unregister(&efi_subsys);
+
+out_free:
 	kfree(variable_name);
-	return 0;
+
+	return error;
 }
 
 static void __exit