From: Joe Perches <joe@perches.com>
To: Dwaipayan Ray <dwaipayanray1@gmail.com>
Cc: linux-kernel@vger.kernel.org,
linux-kernel-mentees@lists.linuxfoundation.org,
Lukas Bulwahn <lukas.bulwahn@gmail.com>
Subject: Re: [PATCH RFC] checkpatch: fix multi-statement macro checks
Date: Thu, 01 Oct 2020 06:42:32 -0700 [thread overview]
Message-ID: <f3dadda8af7eef6613d7a4105170058f2759507d.camel@perches.com> (raw)
In-Reply-To: <CABJPP5CFE3KXzMzuvVxtJt5tOg8Ye6y1V7-mqT5pqazHjVWvJw@mail.gmail.com>
On Thu, 2020-10-01 at 18:57 +0530, Dwaipayan Ray wrote:
> On Thu, Oct 1, 2020 at 6:47 PM Joe Perches <joe@perches.com> wrote:
> > On Thu, 2020-10-01 at 16:03 +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/access.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 parantheses
> > > doesn't make any sense.
> >
> > OK
> >
> > > Checkpatch already has an exception list for such common macro types.
> > > Added a new exception for while (...) {...} style blocks to the same.
> > > This effectively fixed the wrong error message.
> > []
> > > diff --git a/scripts/checkpatch.pl b/scripts/checkpatch.pl
> > []
> > > @@ -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 (...) {...}
Note the \s*
^
> > Did you try to output $dstat for some matching cases?
> > What was the $dstat value for the cases you tried?
> >
> >
> Hi,
> I did check $dstat values.
>
> For example on file mm/maccess.c, there were two such macros:
>
> Case 1:
>
> $ctx:
> +#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); \
> + }
>
> $dstat:
> while 1 1
And perhaps this test should use \s+ instead.
What is $dstat with a #define like:
#define foo(bar,baz)while(bar){bar--;baz++;}
(no spaces anywhere bot the required one after define
> Case 2:
>
> $ctx:
> +#define copy_to_kernel_nofault_loop(dst, src, len, type, err_label) \
> + while (len >= sizeof(type)) { \
> + __put_kernel_nofault(dst, src, type, err_label); \
> + dst += sizeof(type); \
> + src += sizeof(type); \
> + len -= sizeof(type); \
> + }
>
> $dstat:
> while 1 1
>
>
> Thanks,
> Dwaipayan.
next prev parent reply other threads:[~2020-10-01 13:42 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-10-01 10:33 [PATCH RFC] checkpatch: fix multi-statement macro checks Dwaipayan Ray
2020-10-01 11:12 ` Lukas Bulwahn
2020-10-01 13:17 ` Joe Perches
2020-10-01 13:27 ` Dwaipayan Ray
2020-10-01 13:42 ` Joe Perches [this message]
2020-10-01 14:14 ` Dwaipayan Ray
2020-10-01 14:38 ` Joe Perches
2020-10-01 15:26 ` Joe Perches
2020-10-01 15:36 ` Dwaipayan Ray
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