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From: Joe Perches <joe@perches.com>
To: Nick Desaulniers <ndesaulniers@google.com>,
	Trond Myklebust <trond.myklebust@hammerspace.com>,
	Anna Schumaker <anna.schumaker@netapp.com>
Cc: "Gustavo A . R . Silva" <gustavo@embeddedor.com>,
	Nathan Chancellor <natechancellor@gmail.com>,
	Hongxiang Lou <louhongxiang@huawei.com>,
	Miaohe Lin <linmiaohe@huawei.com>,
	linux-nfs@vger.kernel.org, linux-kernel@vger.kernel.org,
	clang-built-linux@googlegroups.com
Subject: Re: [PATCH v2] nfs: remove incorrect fallthrough label
Date: Wed, 16 Sep 2020 13:19:26 -0700	[thread overview]
Message-ID: <ce28bb9bc25cb3f1197f75950a0cfe14947f9002.camel@perches.com> (raw)
In-Reply-To: <20200916200255.1382086-1-ndesaulniers@google.com>

On Wed, 2020-09-16 at 13:02 -0700, Nick Desaulniers wrote:
> There is no case after the default from which to fallthrough to. Clang
> will error in this case (unhelpfully without context, see link below)
> and GCC will with -Wswitch-unreachable.
> 
> The previous commit should have just replaced the comment with a break
> statement.

> If we consider implicit fallthrough to be a design mistake of C, then
> all case statements should be terminated with one of the following
> statements:
> 
> * break
> * continue
> * return
> * __attribute__(__fallthrough__)

Just fallthrough.  __attribute__((__fallthrough__)
is only used once in code for the #define.

And maybe add see: Documentation/process/deprecated.rst

> * goto (plz no)

goto is a valid style inside a switch/case label block.

There are more than 1500 of these goto <label> uses in the
kernel so the 'please no' here doesn't seem reasonable.

> * (call of function with __attribute__(__noreturn__))

I guess panic counts.  I count 11 of those.

Are there any other uses of functions with __noreturn
in switch/case label blocks?



  parent reply	other threads:[~2020-09-16 20:19 UTC|newest]

Thread overview: 19+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-09-15 22:57 [PATCH] " Nick Desaulniers
2020-09-15 23:29 ` Joe Perches
2020-09-15 23:51   ` Gustavo A. R. Silva
2020-09-16  0:01     ` Gustavo A. R. Silva
2020-09-16  0:33       ` Joe Perches
2020-09-16 20:02   ` [PATCH v2] " Nick Desaulniers
2020-09-16 20:18     ` Gustavo A. R. Silva
2020-09-16 20:19     ` Joe Perches [this message]
2020-09-17 21:41       ` Nick Desaulniers
2020-09-18  1:36         ` Joe Perches
2020-09-17 21:45       ` [PATCH v3] " Nick Desaulniers
2020-09-24 17:19         ` Nick Desaulniers
2020-09-24 17:40           ` Joe Perches
2020-09-24 18:07             ` Joe Perches
2020-09-24 18:11               ` Anna Schumaker
2020-09-25 11:27                 ` Mark Brown
2020-09-24 18:08           ` Gustavo A. R. Silva
2020-09-17  4:35     ` [PATCH v2] " Nathan Chancellor
2020-09-17  6:21 linmiaohe

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