On Fri, 2016-06-03 at 10:25 -0500, Nishanth Menon wrote:
> In some functions, returning a -ve decimal value is actually a valid
> return condition when the function is returning a value, however, it
> can also be misused for returning an error value that should ideally
> be a valid error code defined in include/uapi/asm-generic/errno-base.h
> or include/uapi/asm-generic/errno.h
>
> Considering typical newbie error of doing the following:
> int fn(void)
> {
> /* ... error condition ... */
> return -1;
> }
>
> void fn1(void)
> {
> /* some code */
> if (fn() < 0) {
> pr_err("Error occurred\n");
> return;
> }
> /* other cases... */
> }
>
> Flag this as a check case for developer verification.
I think it's not a newbie error to have a -1 return and it
seems like rather too many cases to even suggest be changed.
$ git grep -E "\breturn\s+\-\s*[0-9]+" * | grep -v "^tools" | wc -l
8388
> diff --git a/scripts/checkpatch.pl b/scripts/checkpatch.pl
[]
> @@ -4351,6 +4351,12 @@ sub process {
> }
> }
>
> +# return with a value is not usually a good sign, unless the function is
> supposed to return a value
> + if (defined($stat) && $stat =~ /^.\s*return\s*-[0-9]+\s*;/s) {
> + CHK("RETURN_NUMBER",
> + "Suspect error return with a value, If this is
> error value, refer to include/uapi/asm-generic/errno-base.h and
> include/uapi/asm-generic/errno.h\n" . $herecurr);
> + }
> +
> # unnecessary return in a void function
> # at end-of-function, with the previous line a single leading tab, then
> return;
> # and the line before that not a goto label target like "out:"
