On Fri, 2016-06-03 at 15:02 -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. The notable exception is "-1"
> which has quiet a history of usage as pointed out by Joe Perches.
>
> Considering typical error of doing the following:
> int fn(void)
> {
> /* ... error condition ... */
> return -2;
> }
>
> 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.
>
> The check is done for negative values less than 1 and tools
> directory is exempt from this requirement based on Joe Perches'
> suggestion.
>
> Suggested-by: Joe Perches <[email protected]>
No, I didn't suggest this.
I'm not at all sure it's even a good idea.
> Signed-off-by: Nishanth Menon <[email protected]>
> ---
> Changes in V2:
> - change in regex for check for check for less than 1
> - Update in commit message to the effect
> - Added Suggested-by for Joe's recommendation on regex.
>
> V1: https://patchwork.kernel.org/patch/9153345/
>
> scripts/checkpatch.pl | 6 ++++++
> 1 file changed, 6 insertions(+)
>
> diff --git a/scripts/checkpatch.pl b/scripts/checkpatch.pl
> index 4904ced676d4..a2e677b5fd78 100755
> --- 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 ($realfile !~ /^tools/ && defined($stat) && $stat =~
> /^.\s*return\s*-\s*(?!1\b)\d+\s*;/s) {
I think
if ($realfile != /^tools/ && $line =~ /\breturn\s*-\s*(?!1\b)\d+\s*;/
would be better as it would catch return -2 in a macro or a
multi-line statement like
if (<foo>) return -2;
> + 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);
That's an awfully long message.
Maybe something like:
"Perhaps better to use standard ERRNO system error symbols"
