On Thu, 2020-10-01 at 22:49 +0530, Dwaipayan Ray wrote:
> Checkpatch.pl doesn't have a check for excluding while (...) {...}
> blocks from MULTISTATEMENT_MACRO_USE_DO_WHILE error.
>
> For example, running checkpatch.pl on the file mm/maccess.c in the
> kernel generates the following error:
>
> ERROR: Macros with complex values should be enclosed in parentheses
> +#define copy_from_kernel_nofault_loop(dst, src, len, type, err_label) \
> + while (len >= sizeof(type)) { \
> + __get_kernel_nofault(dst, src, type, err_label); \
> + dst += sizeof(type); \
> + src += sizeof(type); \
> + len -= sizeof(type); \
> + }
>
> The error is misleading for this case. Enclosing it in parentheses
> doesn't make any sense.
>
> Checkpatch already has an exception list for such common macro types.
> Added a new exception for while (...) {...} style blocks to the same.
>
> In addition, the brace flatten logic was modified by changing the
> substitution characters from "1" to "1u". This was done to ensure that
> macros in the form "#define foo(bar) while(bar){bar--;}" were also
> correctly procecssed.
>
> Link:
> https://lore.kernel.org/linux-kernel-mentees/[email protected]/
>
> Suggested-by: Joe Perches <[email protected]>
> Signed-off-by: Dwaipayan Ray <[email protected]>
Thanks. Andrew, can you pick this up please?
> ---
> scripts/checkpatch.pl | 7 ++++---
> 1 file changed, 4 insertions(+), 3 deletions(-)
>
> diff --git a/scripts/checkpatch.pl b/scripts/checkpatch.pl
> index 9e65d21456f1..31624bbb342e 100755
> --- a/scripts/checkpatch.pl
> +++ b/scripts/checkpatch.pl
> @@ -5299,9 +5299,9 @@ sub process {
> $dstat =~ s/\s*$//s;
>
> # Flatten any parentheses and braces
> - while ($dstat =~ s/\([^\(\)]*\)/1/ ||
> - $dstat =~ s/\{[^\{\}]*\}/1/ ||
> - $dstat =~ s/.\[[^\[\]]*\]/1/)
> + while ($dstat =~ s/\([^\(\)]*\)/1u/ ||
> + $dstat =~ s/\{[^\{\}]*\}/1u/ ||
> + $dstat =~ s/.\[[^\[\]]*\]/1u/)
> {
> }
>
> @@ -5342,6 +5342,7 @@ sub process {
> $dstat !~ /^\.$Ident\s*=/ &&
> # .foo =
> $dstat !~ /^(?:\#\s*$Ident|\#\s*$Constant)\s*$/ &&
> # stringification #foo
> $dstat !~ /^do\s*$Constant\s*while\s*$Constant;?$/
> && # do {...} while (...); // do {...} while (...)
> + $dstat !~ /^while\s*$Constant\s*$Constant\s*$/ &&
> # while (...) {...}
> $dstat !~ /^for\s*$Constant$/ &&
> # for (...)
> $dstat !~
> /^for\s*$Constant\s+(?:$Ident|-?$Constant)$/ && # for (...) bar()
> $dstat !~ /^do\s*{/ &&
> # do {...
