Re: [PATCH v3] checkpatch.pl: New instances of ENOSYS are errors

[Andy Lutomirski]

On Fri, Aug 22, 2014 at 11:14 AM, Joe Perches <joe@xxxxxxxxxxx> wrote:
> On Fri, 2014-08-22 at 11:05 -0700, Andy Lutomirski wrote:
>> ENOSYS means that a nonexistent system call was called.  We have a
>> bad habit of using it for things like invalid operations on
>> otherwise valid syscalls.  We should avoid this in new code.
>
> Seems sensible thanks for persisting.
>
> Andrew Morton is generally the upstream path (cc'd)
>
>> Signed-off-by: Andy Lutomirski <luto@xxxxxxxxxxxxxx>
>> ---
>>
>> Pervasive incorrect usage of ENOSYS came up at the kernel summit ABI
>> review discussion.  Let's see if checkpatch can help.
>>
>> I'll submit a separate patch for include/uapi/asm-generic/errno.h.
>>
>> Changes from v2:
>>  - Reduce severity to WARN.
>>  - Remove unnecessary clarification.
>>  - Rebase onto Linus' tree instead of v3.16.
>>
>> Changes from v1:
>>  - Moved later so that it won't warn on context lines.
>>  - Use $herecur.
>>  - Improve regex pattern.
>>
>>  scripts/checkpatch.pl | 8 ++++++++
>>  1 file changed, 8 insertions(+)
>>
>> diff --git a/scripts/checkpatch.pl b/scripts/checkpatch.pl
>> index 31a731e..448d075 100755
>> --- a/scripts/checkpatch.pl
>> +++ b/scripts/checkpatch.pl
>> @@ -3214,6 +3214,14 @@ sub process {
>>                            "Prefer dev_$level(... to dev_printk(KERN_$orig, ...\n" . $herecurr);
>>               }
>>
>> +# ENOSYS means "bad syscall nr" and nothing else.  This will have a small
>> +# number of false positives, but assembly files are not checked, so at
>> +# least the arch entry code will not trigger this warning.
>> +             if ($line =~ /\bENOSYS\b/) {
>> +                     WARN("ENOSYS",
>> +                          "ENOSYS means 'invalid syscall nr' and nothing else\n" . $herecurr);
>> +             }
>> +
>>  # function brace can't be on same line, except for #defines of do while,
>>  # or if closed on same line
>>               if (($line=~/$Type\s*$Ident\(.*\).*\s*{/) and
>
>
>

Ping, akpm?

--Andy

-- 
Andy Lutomirski
AMA Capital Management, LLC
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