Re: [PATCH v1 net-next] checkpatch: Discourage a new use of rtnl_lock() variants.

[Kuniyuki Iwashima <kuniyu@amazon.com>]

From: Paolo Abeni <pabeni@redhat.com>
Date: Thu, 13 Feb 2025 12:03:51 +0100
> > diff --git a/scripts/checkpatch.pl b/scripts/checkpatch.pl
> > index 7b28ad331742..09d5420436cc 100755
> > --- a/scripts/checkpatch.pl
> > +++ b/scripts/checkpatch.pl
> > @@ -6995,6 +6995,12 @@ sub process {
> >  #			}
> >  #		}
> >  
> > +# A new use of rtnl_lock() is discouraged as it's being converted to rtnl_net_lock(net).
> > +		if ($line =~ /^\+.*\brtnl_(try)?lock(_interruptible|_killable)?\(\)/) {
> 
> I think you need to add '\s*' just before  '\(' to avoid the test being
> fooled by some bad formatting.

Will add that.  BTW, it's also caught by another warning.

  WARNING: space prohibited between function name and open parenthesis '('
  #18: FILE: net/core/rtnetlink.c:79:
  +	rtnl_lock ();


> Also I'm unsure if the '^\+.*' header is strictly required - it should
> but some/most existing tests don't use it, do you know why?

I didn't notice but exactly, the following matches only + line.

  if ($line =~ /\brtnl_(try)?lock(_interruptible|_killable)?\s*\(\)/) {

Looks like the '-' diff is filtered, matching '-' doesn't make sense.

This function looks suspicious ? (maybe wrong, I'm not familiar with perl)

---8<---
sub raw_line {
        my ($linenr, $cnt) = @_;

        my $offset = $linenr - 1;
        $cnt++;

        my $line;
        while ($cnt) {
                $line = $rawlines[$offset++];
                next if (defined($line) && $line =~ /^-/);
                $cnt--;
        }

        return $line;
}
---8<---

Thanks!