Re: netdev/checkpatch issue

Re: netdev/checkpatch issue

[Joe Perches]

On Thu, 2023-02-02 at 13:55 +0000, 陶 缘 wrote:
> Hi, Dear checkpatch experts:
> 
>       I may encountered a false-postive issue on checkpatch function.

I think not.
Perhaps send me as an attachment the specific patch file where
you get this error.

Re: 回复: netdev/checkpatch issue

[Joe Perches]

On Thu, 2023-02-02 at 23:42 +0000, 陶 缘 wrote:
> Hi, Joe:
>       Thanks a lot for your time.
>       I put it in the attachment, in case you prefer plain text content in email, i also append it at the end
> by the way, could you let me know if the 'netdev/checkpatch' is calling ./scripts/checkpatch.pl

As I have no idea what netdev/checkpatch is, i have no idea.

The checkpatch script in the kernel does not produce an error
for this input.

Re: 回复: netdev/checkpatch issue

[Lukas Bulwahn]

On Fri, Feb 3, 2023 at 8:29 AM Joe Perches <joe@perches.com> wrote:
>
> On Thu, 2023-02-02 at 23:42 +0000, 陶 缘 wrote:
> > Hi, Joe:
> >       Thanks a lot for your time.
> >       I put it in the attachment, in case you prefer plain text content in email, i also append it at the end
> > by the way, could you let me know if the 'netdev/checkpatch' is calling ./scripts/checkpatch.pl
>
> As I have no idea what netdev/checkpatch is, i have no idea.
>
> The checkpatch script in the kernel does not produce an error
> for this input.

Hi Eddy, Hi Joe,

It seems that the netdev/checkpatch is a checkpatch invocation with
some further configuration setup. Unfortunately, I could not find out
the actual setup, probably hidden somewhere in the patchwork
configuration of that instance. Maybe some netdev patchwork
administrator can share the actual command that is invoked here.

However, I can explain the printed error message. By default,
./scripts/checkpatch.pl uses a max_line_length of 100---see
checkpatch.pl line "my $max_line_length = 100;". The netdev checkpatch
invocation is overriding that and setting it to 80 characters. When,
you run ./scripts/checkpatch.pl --max-line-length=80
net-next-v3-1-1-net-openvswitch-reduce-cpu_used_mask-memory.patch, you
will see the error message that netdev checkpatch shows:

WARNING: line length of 82 exceeds 80 columns
#129: FILE: net/openvswitch/flow.c:110:
+ cpumask_set_cpu(cpu, flow->cpu_used_mask);

total: 0 errors, 1 warnings, 0 checks, 64 lines checked

NOTE: For some of the reported defects, checkpatch may be able to
      mechanically convert to the typical style using --fix or --fix-inplace.

net-next-v3-1-1-net-openvswitch-reduce-cpu_used_mask-memory.patch has
style problems, please review.

NOTE: If any of the errors are false positives, please report
      them to the maintainer, see CHECKPATCH in MAINTAINERS.


So, it is clear that this line, net/openvswitch/flow.c:110, is 82
characters long. So, you counted the characters differently. You need
to consider that a tab counts as 8 characters wide, which in my editor
then leads to a line with 82 characters.

It is up to you and netdev maintainers how to proceed. Checkpatch is
not buggy here, but if you have a line with 82 characters (due to the
many tabs) and you run ./scripts/checkpatch.pl --max-line-length=80,
checkpatch rightfully complains to you.

I hope this helps.

Best regards,

Lukas

Re: 回复: netdev/checkpatch issue

[Lukas Bulwahn]

On Fri, Feb 3, 2023 at 9:44 AM 陶 缘 <taoyuan_eddy@hotmail.com> wrote:
>
> Hi, Lukas:
>       Such a co-incidence, i just shot out the v4 submission:)
>
> Your analysis is convincing, the only thing is that i count the width in the specific line, it is 60+ characters, way below 80.
>
> let me check the script see if i can find anything
>

We assume a tabsize of eight characters, see "my $tabsize = 8;". That
is defined in the kernel coding guidelines.

Lukas