int efivar_init()

in efi/vars.c [414:508]
69 lines of code
14 McCabe index (conditional complexity)

int efivar_init(int (*func)(efi_char16_t *, efi_guid_t, unsigned long, void *),
		void *data, bool duplicates, struct list_head *head)
{
	const struct efivar_operations *ops;
	unsigned long variable_name_size = 1024;
	efi_char16_t *variable_name;
	efi_status_t status;
	efi_guid_t vendor_guid;
	int err = 0;

	if (!__efivars)
		return -EFAULT;

	ops = __efivars->ops;

	variable_name = kzalloc(variable_name_size, GFP_KERNEL);
	if (!variable_name) {
		printk(KERN_ERR "efivars: Memory allocation failed.\n");
		return -ENOMEM;
	}

	if (down_interruptible(&efivars_lock)) {
		err = -EINTR;
		goto free;
	}

	/*
	 * Per EFI spec, the maximum storage allocated for both
	 * the variable name and variable data is 1024 bytes.
	 */

	do {
		variable_name_size = 1024;

		status = ops->get_next_variable(&variable_name_size,
						variable_name,
						&vendor_guid);
		switch (status) {
		case EFI_SUCCESS:
			if (duplicates)
				up(&efivars_lock);

			variable_name_size = var_name_strnsize(variable_name,
							       variable_name_size);

			/*
			 * Some firmware implementations return the
			 * same variable name on multiple calls to
			 * get_next_variable(). Terminate the loop
			 * immediately as there is no guarantee that
			 * we'll ever see a different variable name,
			 * and may end up looping here forever.
			 */
			if (duplicates &&
			    variable_is_present(variable_name, &vendor_guid,
						head)) {
				dup_variable_bug(variable_name, &vendor_guid,
						 variable_name_size);
				status = EFI_NOT_FOUND;
			} else {
				err = func(variable_name, vendor_guid,
					   variable_name_size, data);
				if (err)
					status = EFI_NOT_FOUND;
			}

			if (duplicates) {
				if (down_interruptible(&efivars_lock)) {
					err = -EINTR;
					goto free;
				}
			}

			break;
		case EFI_UNSUPPORTED:
			err = -EOPNOTSUPP;
			status = EFI_NOT_FOUND;
			break;
		case EFI_NOT_FOUND:
			break;
		default:
			printk(KERN_WARNING "efivars: get_next_variable: status=%lx\n",
				status);
			status = EFI_NOT_FOUND;
			break;
		}

	} while (status != EFI_NOT_FOUND);

	up(&efivars_lock);
free:
	kfree(variable_name);

	return err;
}