Re: [PATCH] mips/oprofile: Fix fallthrough placement

From: He Zhe
Date: Fri Aug 21 2020 - 04:46:52 EST




On 8/21/20 3:48 PM, Thomas Bogendoerfer wrote:
> On Thu, Aug 20, 2020 at 08:54:40PM +0800, zhe.he@xxxxxxxxxxxxx wrote:
>> From: He Zhe <zhe.he@xxxxxxxxxxxxx>
>>
>> We want neither
>> "
>> include/linux/compiler_attributes.h:201:41: warning: statement will never
>> be executed [-Wswitch-unreachable]
>> 201 | # define fallthrough __attribute__((__fallthrough__))
>> | ^~~~~~~~~~~~~
>> "
>> nor
>> "
>> include/linux/compiler_attributes.h:201:41: warning: attribute
>> 'fallthrough' not preceding a case label or default label
>> 201 | # define fallthrough __attribute__((__fallthrough__))
>> | ^~~~~~~~~~~~~
>> "
>>
>> It's not worth adding one more macro. Let's simply place the fallthrough
>> in between the expansions.
>>
>> Signed-off-by: He Zhe <zhe.he@xxxxxxxxxxxxx>
> there is already another patch for the problem, which I've applied
> to mips-fixes.

You mean the below one?
https://git.kernel.org/pub/scm/linux/kernel/git/mips/linux.git/commit/?h=mips-fixes&id=5900acb374fe2f4f42bbcb2c84db64f582d917a1

That patch handles the first warning in my commit log but does not handle the
second one which is introduced since gcc v10.1.0 commit 6c80b1b56dec
("Make more bad uses of fallthrough attribute into pedwarns.").

Zhe

>
> Thomas.
>