linux-kernel - Re: [PATCH v3 2/4] objtool: Move orc outside of check

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Date:   Fri, 31 Jul 2020 09:19:27 +0100
From:   Julien Thierry <jthierry@...hat.com>
To:     Miroslav Benes <mbenes@...e.cz>
Cc:     Josh Poimboeuf <jpoimboe@...hat.com>, peterz@...radead.org,
        linux-kernel@...r.kernel.org
Subject: Re: [PATCH v3 2/4] objtool: Move orc outside of check



On 7/31/20 8:56 AM, Miroslav Benes wrote:
> On Thu, 30 Jul 2020, Julien Thierry wrote:
> 
>>
>>
>> On 7/30/20 3:15 PM, Josh Poimboeuf wrote:
>>> On Thu, Jul 30, 2020 at 02:29:20PM +0100, Julien Thierry wrote:
>>>>
>>>>
>>>> On 7/30/20 2:22 PM, peterz@...radead.org wrote:
>>>>> On Thu, Jul 30, 2020 at 01:40:42PM +0100, Julien Thierry wrote:
>>>>>>
>>>>>>
>>>>>> On 7/30/20 10:57 AM, peterz@...radead.org wrote:
>>>>>>> On Thu, Jul 30, 2020 at 10:41:41AM +0100, Julien Thierry wrote:
>>>>>>>> +		if (file->elf->changed)
>>>>>>>> +			return elf_write(file->elf);
>>>>>>>> +		else
>>>>>>>> +			return 0;
>>>>>>>>       }
>>>>>>>
>>>>>>> I think we can do without that else :-)
>>>>>>>
>>>>>>
>>>>>> I did wonder and was not 100% confident about it, but the orc gen will
>>>>>> always change the file, correct?
>>>>>
>>>>> Not if it already has orc, iirc.
>>>>>
>>>>> But what I was trying to say is that:
>>>>>
>>>>>   if (file->elf->changed)
>>>>>    return elf_write(file->elf)
>>>>>
>>>>>   return 0;
>>>>>
>>>>> is identical code and, IMO, easier to read.
>>>>>
>>>>
>>>> Much easier yes, I'll change it.
>>>
>>> But I think file->elf->changed can be assumed at this point anyway, so
>>> it could just be an unconditional
>>>
>>>   return elf_write(file->elf);
>>>
>>
>> I'll triple check whether that's the case and remove the if if possible.
> 
> I think it is the case. And even if not, it would only cause a pointless
> call to elf_update() in the end and that should not do any harm anyway if
> I am not mistaken.
> 
> However, I think there is a problem with the rebase on top of the current
> code. The patch moves elf_write() call to orc_gen.c which was ok before
> Peterz introduced elf_write_insn() et al. We need to keep elf_write() in
> check.c for this case too.
> 

Yes, you're right. Looks like I messed things up with the rebase. That 
means I might have to move the elf_write() to builtin-check.c.

Thanks for pointing it out.

-- 
Julien Thierry