[Linux-kernel-mentees] [PATCH v4] checkpatch: extend attributes check to handle more patterns

[Joe Perches]

On Sun, 2020-10-25 at 12:21 +0530, Dwaipayan Ray wrote:
> It is generally preferred that the macros from
> include/linux/compiler_attributes.h are used, unless there
> is a reason not to.
> 
> checkpatch currently checks __attribute__ for each of
> packed, aligned, printf, scanf, and weak. Other declarations
> in compiler_attributes.h are not handled.
> 
> Add a generic test to check the presence of such attributes.
> Some attributes require more specific handling and are kept
> separate.
[]
> Also add fixes for the generic attributes check.
[]
> diff --git a/scripts/checkpatch.pl b/scripts/checkpatch.pl
[]
> +				if (exists($attr_list{$curr_attr})) {
> +					my $new = $attr_list{$curr_attr};
> +					if (WARN("PREFER_DEFINED_ATTRIBUTE_MACRO",
> +					         "$new$params is preferred over __attribute__(($attr))\n" . $herecurr) &&
> +						$fix) {
> +						$fixed[$fixlinenr] =~ s/\b__attribute__\s*\(\s*\(\s*\Q$attr\E\s*\)\s*\)/$new$params/;

Thanks.

This fix would only work for the single conversions
and would not work for multiple attributes like:

	__attribute__((aligned(4), packed))

It would be nice to be able to convert this to

	__aligned(4) __packed

One mechanism to do that might be to:

	create an empty array
	for each attr
		push(@array, conversion)
	s/__attribute__(...)/join(' ', @array)/

if all attrs were converted.