2018-07-03 23:43:44

by Prakruthi Deepak Heragu

Subject: [PATCH v1] checkpatch: Check for invalid return codes

The only valid integer return is 0, anything else
following "return" should be -ERRCODE or a function. Also, display context
so that the user knows where the return value is incorrect.

http://lkml.org/lkml/2010/7/23/318
There's lots of "return -1;" statements in this patch - it's obscene
that this is used to indicate "some error occurred" in kernel space
rather than a real errno value - even when an existing function
(eg, request_irq) gave you an error code already.

Signed-off-by: Patrick Pannuto <[email protected]>
Signed-off-by: Stepan Moskovchenko <[email protected]>
Signed-off-by: Prakruthi Deepak Heragu <[email protected]>
---
Changes in v1:
- Use CHK instead of ERROR
- Rephrase the warning message
- Provide the file name and line number where return value is incorrect

scripts/checkpatch.pl | 6 ++++++
1 file changed, 6 insertions(+)

diff --git a/scripts/checkpatch.pl b/scripts/checkpatch.pl
index a9c0550..2808c27 100755
--- a/scripts/checkpatch.pl
+++ b/scripts/checkpatch.pl
@@ -6197,6 +6197,12 @@ sub process {
"switch default: should use break\n" . $herectx);
}

+# check for return codes on error paths
+ if ($line =~ /\breturn\s+-\d+/) {
+ CHK("NO_ERROR_CODE",
+ "invalid return value, please return -<APPROPRIATE_ERRNO>\n" . $herecurr);
+ }
+
# check for gcc specific __FUNCTION__
if ($line =~ /\b__FUNCTION__\b/) {
if (WARN("USE_FUNC",
--
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2018-07-04 01:41:58

by Joe Perches

Subject: Re: [PATCH v1] checkpatch: Check for invalid return codes

On Tue, 2018-07-03 at 16:41 -0700, Prakruthi Deepak Heragu wrote:
> The only valid integer return is 0, anything else
> following "return" should be -ERRCODE or a function.

Integer return values can be positive constant and correct.

So perhaps better:

Negative integer return codes should prefer to use #define -<ERRNO>
values instead of negative numbers.

> Also, display context
> so that the user knows where the return value is incorrect.
>
> http://lkml.org/lkml/2010/7/23/318
> There's lots of "return -1;" statements in this patch - it's obscene
> that this is used to indicate "some error occurred" in kernel space
> rather than a real errno value - even when an existing function
> (eg, request_irq) gave you an error code already.

This bit is superfluous and if you are going to quote
someone in a patch commit, it's nice to cc: them.

> Signed-off-by: Patrick Pannuto <[email protected]>
> Signed-off-by: Stepan Moskovchenko <[email protected]>
> Signed-off-by: Prakruthi Deepak Heragu <[email protected]>

Does it really take 3 people to sign-off on this patch?

> ---
> Changes in v1:
> - Use CHK instead of ERROR
> - Rephrase the warning message
> - Provide the file name and line number where return value is incorrect
>
> scripts/checkpatch.pl | 6 ++++++
> 1 file changed, 6 insertions(+)
>
> diff --git a/scripts/checkpatch.pl b/scripts/checkpatch.pl
> index a9c0550..2808c27 100755
> --- a/scripts/checkpatch.pl
> +++ b/scripts/checkpatch.pl
> @@ -6197,6 +6197,12 @@ sub process {
> "switch default: should use break\n" . $herectx);
> }
>
> +# check for return codes on error paths



> + if ($line =~ /\breturn\s+-\d+/) {
> + CHK("NO_ERROR_CODE",

NO_ERROR_CODE isn't very obvious to me.
How about NEGATIVE_ERRNO or APPROPRIATE_ERRNO

> + "invalid return value, please return -<APPROPRIATE_ERRNO>\n" . $herecurr);
> + }
> +
> # check for gcc specific __FUNCTION__
> if ($line =~ /\b__FUNCTION__\b/) {
> if (WARN("USE_FUNC",