Subject: Re: [PATCH 1/3] checkpatch.pl: add missing memory barriers

From: Joe Perches <[email-masked]>
Date: Mon, 04 Jan 2016 08:07:40 -0800

On Mon, 2016-01-04 at 13:36 +0200, Michael S. Tsirkin wrote:
> SMP-only barriers were missing in checkpatch.pl
> 
> Refactor code slightly to make adding more variants easier.
> 
> Signed-off-by: Michael S. Tsirkin <[email-masked]>
> ---
>  scripts/checkpatch.pl | 9 ++++++++-
>  1 file changed, 8 insertions(+), 1 deletion(-)
> 
> diff --git a/scripts/checkpatch.pl b/scripts/checkpatch.pl
> index 2b3c228..0245bbe 100755
> --- a/scripts/checkpatch.pl
> +++ b/scripts/checkpatch.pl
> @@ -5116,7 +5116,14 @@ sub process {
>  			}
>  		}
>  # check for memory barriers without a comment.
> -		if ($line =~ /\b(mb|rmb|wmb|read_barrier_depends|smp_mb|smp_rmb|smp_wmb|smp_read_barrier_depends)\(/) {
> +
> +		my @barriers = ('mb', 'rmb', 'wmb', 'read_barrier_depends');
> +		my @smp_barriers = ('smp_store_release', 'smp_load_acquire', 'smp_store_mb');
> +
> +		@smp_barriers = (@smp_barriers, map {"smp_" . $_} @barriers);

I think using map, which so far checkpatch doesn't use,
makes smp_barriers harder to understand and it'd be
better to enumerate them.

> +		my $all_barriers = join('|', (@barriers, @smp_barriers));
> +
> +		if ($line =~ /\b($all_barriers)\(/) {

It would be better to use /\b$all_barriers\s*\(/
as there's no reason for the capture and there
could be a space between the function and the
open parenthesis.

>  			if (!ctx_has_comment($first_line, $linenr)) {
>  				WARN("MEMORY_BARRIER",
>  				     "memory barrier without comment\n" . $herecurr);