linux-kernel - Re: [PATCH] net: xfrm_user: use BUG_ON instead of if condition followed by BUG

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Message-ID: <20171025114351.Horde.MQ4XGlIueQ50FhD0JRZ9B-o@gator4166.hostgator.com>
Date:   Wed, 25 Oct 2017 11:43:51 -0500
From:   "Gustavo A. R. Silva" <garsilva@...eddedor.com>
To:     Steffen Klassert <steffen.klassert@...unet.com>
Cc:     David Miller <davem@...emloft.net>, herbert@...dor.apana.org.au,
        netdev@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH] net: xfrm_user: use BUG_ON instead of if condition
 followed by BUG

Hi all,

Quoting Steffen Klassert <steffen.klassert@...unet.com>:

> On Wed, Oct 25, 2017 at 01:22:22PM +0900, David Miller wrote:
>> From: Herbert Xu <herbert@...dor.apana.org.au>
>> Date: Wed, 25 Oct 2017 12:05:41 +0800
>>
>> > On Tue, Oct 24, 2017 at 05:48:42PM +0900, David Miller wrote:
>> >>
>> >> This discussion has happened before.
>> >>
>> >> But I'll explain the conclusion here for your benefit.
>> >>
>> >> BUG_ON() is a statement and everything inside of it will
>> >> always execute.
>> >>
>> >> BUG_ON() is always preferred because it allows arch
>> >> specific code to pass the conditional result properly
>> >> into inline asm and builtins for optimal code generation.
>> >
>> > This is a good point.  However, while a little bit more verbose you
>> > can still achieve the same assembly-level result by something like
>> >
>> > 	int err;
>> >
>> > 	err = <insert real code here>;
>> > 	BUG_ON(err);
>> >
>> > Having real code in BUG_ON may pose problems to people reading the
>> > code because some of us tend to ignore code in BUG_ON and similar
>> > macros such as BUILD_BUG_ON.
>>
>> I agree that this makes the code easier to read and audit.
>
> It seems that we have an agreement on the above version,
> Gustavo can you please update your patches to this?
>

I can do that. I'll work on a patchset for this.

Thanks
--
Gustavo A. R. Silva