From: Herbert Xu <herbert@gondor.apana.org.au>
To: David Miller <davem@davemloft.net>
Cc: garsilva@embeddedor.com, steffen.klassert@secunet.com,
netdev@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH] net: xfrm_user: use BUG_ON instead of if condition followed by BUG
Date: Wed, 25 Oct 2017 12:05:41 +0800 [thread overview]
Message-ID: <20171025040541.GA1999@gondor.apana.org.au> (raw)
In-Reply-To: <20171024.174842.272234711073180328.davem@davemloft.net>
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.
Cheers,
--
Email: Herbert Xu <herbert@gondor.apana.org.au>
Home Page: http://gondor.apana.org.au/~herbert/
PGP Key: http://gondor.apana.org.au/~herbert/pubkey.txt
next prev parent reply other threads:[~2017-10-25 4:06 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-10-23 18:18 Gustavo A. R. Silva
2017-10-24 3:25 ` Herbert Xu
2017-10-24 3:50 ` Gustavo A. R. Silva
2017-10-24 3:53 ` Herbert Xu
2017-10-24 3:57 ` Gustavo A. R. Silva
2017-10-24 4:01 ` Alexei Starovoitov
2017-10-24 4:30 ` Herbert Xu
2017-10-24 8:48 ` David Miller
2017-10-25 4:05 ` Herbert Xu [this message]
2017-10-25 4:22 ` David Miller
2017-10-25 7:28 ` Steffen Klassert
2017-10-25 16:43 ` Gustavo A. R. Silva
2017-10-26 0:38 ` Gustavo A. R. Silva
2017-10-26 6:36 ` Herbert Xu
2017-10-26 10:47 ` Gustavo A. R. Silva
2017-10-26 11:31 ` [PATCH v2] " Gustavo A. R. Silva
2017-10-27 10:46 ` Steffen Klassert
2017-10-27 20:56 ` Gustavo A. R. Silva
2017-10-24 8:47 ` [PATCH] " David Miller
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