# Re: \[PATCH v2 2/3\] checkpatch: check for \_\_smp outside barrier.h

- From: Joe Perches \<joe@perches.com\>
- Date: 2016-01-10 15:08:47 
- List: linuxppc-dev
- Page: https://ratatoskr.run/linuxppc-dev/2016/01/4656845
- Thread: https://ratatoskr.run/linux-arch/2016/01/4656776/t.md

```text
On Sun, 2016-01-10 at 13:57 +0200, Michael S. Tsirkin wrote:
> Introduction of __smp barriers cleans up a bunch of duplicate code, but
> it gives people an additional handle onto a "new" set of barriers - just
> because they're prefixed with __* unfortunately doesn't stop anyone from
> using it (as happened with other arch stuff before.)
> 
> Add a checkpatch test so it will trigger a warning.
[]
> diff --git a/scripts/checkpatch.pl b/scripts/checkpatch.pl
[]
> @@ -5141,6 +5141,16 @@ sub process {
>  			}
>  		}
>  
> +		my $underscore_smp_barriers = qr{__smp_($smp_barriers)}x;

another unnecessary capture group

> +
> +		if ($realfile !~ m@^include/asm-generic/@ &&
> +		    $realfile !~ m@/barrier\.h$@ &&
> +		    $line =~ m/\b($underscore_smp_barriers)\s*\(/ &&
> +		    $line !~ m/^.\s*\#\s*define\s+($underscore_smp_barriers)\s*\(/) {
> +			WARN("MEMORY_BARRIER",
> +			     "__smp memory barriers shouldn't be used outside barrier.h and asm-generic\n" . $herecurr);
> +		}
> +
>  # check for waitqueue_active without a comment.
>  		if ($line =~ /\bwaitqueue_active\s*\(/) {
>  			if (!ctx_has_comment($first_line, $linenr)) {
```