Re: [PATCH 02/10] KVM: x86: MMU: Add helper function to clear a bit in unsync child bitmap

From: Takuya Yoshikawa <yoshikawa_takuya_b1@lab.ntt.co.jp>
To: Xiao Guangrong <guangrong.xiao@linux.intel.com>, pbonzini@redhat.com
Cc: kvm@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH 02/10] KVM: x86: MMU: Add helper function to clear a bit in unsync child bitmap
Date: Thu, 19 Nov 2015 13:02:53 +0900	[thread overview]
Message-ID: <564D49ED.3020101@lab.ntt.co.jp> (raw)
In-Reply-To: <564D3816.8080609@linux.intel.com>

On 2015/11/19 11:46, Xiao Guangrong wrote:

>> Actually, some people prefer to put braces when one of the
>> if/else-if/else cases has multiple lines.  You can see
>> some examples in kernel/sched/core.c: see hrtick_start(),
>> sched_fork(), free_sched_domain().
>>
>> In our case, I thought putting braces would align the else-if
>> and else and make the code look a bit nicer, but I know this
>> may be just a matter of personal feeling.
>>
>> In short, unless the maintainer, Paolo for this file, has any
>> preference, both ways will be accepted.
>
> The reason why i pointed this out is that it is the style documented
> in Documentation/CodingStyle:
> | Do not unnecessarily use braces where a single statement will do.
> |
> |        if (condition)
> |                action();
> |

Ah, this is a different thing.  For this case, there is a consensus
and checkpatch will complain if we don't obey the rule.

What I explained was:

   if (condition) {
      line1;
      line2;  // multiple lines
   } else if {
      single-line-statement;  -- (*1)
   } else
      single-line-statement;  -- (*2)

For (*1) and (*2), especially for (*1), some people put braces.

> Actually, Ingo Molnar hated this braces-style too much and blamed
> many developers who used this style (include me, that why i was
> nervous to see this style :( ).

I think he likes the coding style of kernel/sched/core.c very much,
as you know.  Actually that is one reason why I took it as an example.

Let's just choose the way which Paolo prefers for this time, I don't
know which is better.

Thank you,
   Takuya