From: Douglas Gilbert <dgilbert@interlog.com>
To: Joe Perches <joe@perches.com>, Andrew Morton <akpm@linux-foundation.org>
Cc: LKML <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH] checkpatch: Improve TYPECAST_INT_CONSTANT test message
Date: Mon, 18 Jan 2021 15:16:42 -0500 [thread overview]
Message-ID: <1afecb44-cc40-c943-8d6e-eb3f50eaa9f9@interlog.com> (raw)
In-Reply-To: <ecefe8dcb93fe7028311b69dd297ba52224233d4.camel@perches.com>
On 2021-01-18 12:19 p.m., Joe Perches wrote:
> Improve the TYPECAST_INT_CONSTANT test by showing the suggested
> conversion for various type of uses like (unsigned int)1 to 1U.
The questionable code snippet was:
unsigned int nent, nalloc;
....
if (check_add_overflow(nent, (unsigned int)1, &nalloc))
where the check_add_overflow() macro [include/linux/overflow.h]
uses typeid to check its first and second arguments have the
same type. So it is likely others could meet this issue.
Doug Gilbert
> Signed-off-by: Joe Perches <joe@perches.com>
> ---
>
> Douglas Gilbert sent me a private email (and in that email said he
> 'loves to hate checkpatch' ;) complaining that checkpatch warned on the
> use of the cast of '(unsigned int)1' so make it more obvious why the
> message is emitted by always showing the suggested conversion.
>
> scripts/checkpatch.pl | 20 ++++++++++----------
> 1 file changed, 10 insertions(+), 10 deletions(-)
>
> diff --git a/scripts/checkpatch.pl b/scripts/checkpatch.pl
> index 016115a62a9f..4f8494527139 100755
> --- a/scripts/checkpatch.pl
> +++ b/scripts/checkpatch.pl
> @@ -6527,18 +6527,18 @@ sub process {
> if ($line =~ /(\(\s*$C90_int_types\s*\)\s*)($Constant)\b/) {
> my $cast = $1;
> my $const = $2;
> + my $suffix = "";
> + my $newconst = $const;
> + $newconst =~ s/${Int_type}$//;
> + $suffix .= 'U' if ($cast =~ /\bunsigned\b/);
> + if ($cast =~ /\blong\s+long\b/) {
> + $suffix .= 'LL';
> + } elsif ($cast =~ /\blong\b/) {
> + $suffix .= 'L';
> + }
> if (WARN("TYPECAST_INT_CONSTANT",
> - "Unnecessary typecast of c90 int constant\n" . $herecurr) &&
> + "Unnecessary typecast of c90 int constant - '$cast$const' could be '$const$suffix'\n" . $herecurr) &&
> $fix) {
> - my $suffix = "";
> - my $newconst = $const;
> - $newconst =~ s/${Int_type}$//;
> - $suffix .= 'U' if ($cast =~ /\bunsigned\b/);
> - if ($cast =~ /\blong\s+long\b/) {
> - $suffix .= 'LL';
> - } elsif ($cast =~ /\blong\b/) {
> - $suffix .= 'L';
> - }
> $fixed[$fixlinenr] =~ s/\Q$cast\E$const\b/$newconst$suffix/;
> }
> }
>
>
prev parent reply other threads:[~2021-01-18 20:18 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <f11f2ee7-a909-6ab7-f5a8-67a46e11c1e5@interlog.com>
[not found] ` <63178794d14d12f28ccf87707f420ba97b90f6fd.camel@perches.com>
[not found] ` <b9861410-f23d-62aa-cdc9-9e2918359a86@interlog.com>
2021-01-18 17:19 ` [PATCH] checkpatch: Improve TYPECAST_INT_CONSTANT test message Joe Perches
2021-01-18 20:16 ` Douglas Gilbert [this message]
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