Re: [PATCH v7 1/6] selftests/mm: make file helpers return errors

["David Hildenbrand (Arm)" <david@kernel.org>]

On 8/13/26 20:12, Sarthak Sharma wrote:
> Change read_file(), write_file(), read_num(), write_num() and
> write_num_ignore_einval() in vm_util.c to report failures to callers
> instead of exiting from the helper.
> 
> Make read_file() return a negative errno on failure and 0 on success, so
> callers can distinguish a successful read from an I/O error. Also make
> read_num() reject negative and malformed values.
> 
> Keep write_num_ignore_einval() silent for -EINVAL while returning other
> errors to its caller.
> 
> Update callers to print diagnostics and fail wherever required. Also add
> a helper print_file_access_error() in hugepage_settings.c to print
> TAP-compatible errors without a kselftest dependency. This prepares the
> helpers to be moved to tools/lib/mm without a kselftest dependency.
> 
> Signed-off-by: Sarthak Sharma <sarthak.sharma@arm.com>
> ---

[...]

> -unsigned long read_num(const char *path)
> +int read_num(const char *path, unsigned long *num)
>  {
> +	unsigned long val;
> +	int ret;
>  	char buf[21];
> +	char *end;
>  
> -	if (!read_file(path, buf, sizeof(buf)))
> -		ksft_exit_fail_perror("read_file()");
> +	if (!num)
> +		return -EINVAL;
>  
> -	return strtoul(buf, NULL, 10);
> +	ret = read_file(path, buf, sizeof(buf));
> +	if (ret)
> +		return ret;
> +
> +	if (buf[0] < '0' || buf[0] > '9')
> +		return -EINVAL;

This is to reject any negative or hexadecimal numbers I assume?

(essentially anything that's not a valid number)

Worth adding a comment.


Apart from that LGTM

Acked-by: David Hildenbrand (Arm) <david@kernel.org>

-- 
Cheers,

David