linux-kernel - Re: [PATCH *-next 01/18] mm/mmu_gather: Remove needless return in void API tlb_remove

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Message-ID: <d70d059e-37aa-431d-986c-5666f006d610@icloud.com>
Date: Wed, 26 Feb 2025 19:30:20 +0800
From: Zijun Hu <zijun_hu@...oud.com>
To: Przemek Kitszel <przemyslaw.kitszel@...el.com>
Cc: Zijun Hu <quic_zijuhu@...cinc.com>, Peter Zijlstra
 <peterz@...radead.org>, Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
 Will Deacon <will@...nel.org>, "Aneesh Kumar K.V" <aneesh.kumar@...nel.org>,
 Andrew Morton <akpm@...ux-foundation.org>, Nick Piggin <npiggin@...il.com>,
 Arnd Bergmann <arnd@...db.de>, Thomas Gleixner <tglx@...utronix.de>,
 Herbert Xu <herbert@...dor.apana.org.au>,
 "David S. Miller" <davem@...emloft.net>,
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 linux-mtd@...ts.infradead.org
Subject: Re: [PATCH *-next 01/18] mm/mmu_gather: Remove needless return in
 void API tlb_remove_page()

On 2025/2/26 01:27, Przemek Kitszel wrote:
>>>>> It might not be your preferred coding style, but it is not completely
>>>>> pointless.
>>>>
>>>> based on below C spec such as C17 description. i guess language C does
>>>> not like this usage "return void function in void function";
>>>
>>> This is GNU extension IIRC. Note kernel uses GNU11, not C11
>>
>> any link to share about GNU11's description for this aspect ? (^^)
> this is new for C17 or was there for long time?
> 

Standard C spec has that description for long time.
Standard C11 spec also has that description.

> even if this is an extension, it is very nice for generating locked
> wrappers, so you don't have to handle void case specially
> 
> void foo_bar(...)
> {
>     lockdep_assert_held(&a_lock);
>     /// ...
> }
> 
> // generated
> void foo_bar_lock(...)
> {
>     scoped_guard(mutex, &a_lock)
>         return foo_bar(...);

above is able to be written as below:
      scoped_guard(mutex, &a_lock) {
	foo_bar(...);
	return;
      }
> }
i will list my reasons why this usage "return void function in void
function" is not good in cover letter [00/18] of this series.