linux-kernel - Re: [PATCH v16 2/3] mm: memory-failure: move return value documentation to function declaration

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Message-ID: <4decd52b-a2c9-4e04-9793-4d1553689b92@linux.alibaba.com>
Date: Wed, 6 Nov 2024 14:12:17 +0800
From: Shuai Xue <xueshuai@...ux.alibaba.com>
To: Yazen Ghannam <yazen.ghannam@....com>
Cc: mark.rutland@....com, catalin.marinas@....com, mingo@...hat.com,
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Subject: Re: [PATCH v16 2/3] mm: memory-failure: move return value
 documentation to function declaration



在 2024/11/5 23:18, Yazen Ghannam 写道:
> On Mon, Nov 04, 2024 at 09:54:29AM +0800, Shuai Xue wrote:
>> Part of return value comments for memory_failure() were originally
>> documented at the call site. Move those comments to the function
>> declaration to improve code readability and to provide developers with
>> immediate access to function usage and return information.
>>
>> Signed-off-by: Shuai Xue <xueshuai@...ux.alibaba.com>
>> Reviewed-by: Jarkko Sakkinen <jarkko@...nel.org>
>> Reviewed-by: Jonathan Cameron <Jonathan.Cameron@...wei.com>
>> ---
>>   arch/x86/kernel/cpu/mce/core.c | 7 -------
>>   mm/memory-failure.c            | 9 ++++++---
>>   2 files changed, 6 insertions(+), 10 deletions(-)
>>
>> diff --git a/arch/x86/kernel/cpu/mce/core.c b/arch/x86/kernel/cpu/mce/core.c
>> index 2a938f429c4d..c90d8fcd246a 100644
>> --- a/arch/x86/kernel/cpu/mce/core.c
>> +++ b/arch/x86/kernel/cpu/mce/core.c
>> @@ -1373,13 +1373,6 @@ static void kill_me_maybe(struct callback_head *cb)
>>   		return;
>>   	}
>>   
>> -	/*
>> -	 * -EHWPOISON from memory_failure() means that it already sent SIGBUS
>> -	 * to the current process with the proper error info,
>> -	 * -EOPNOTSUPP means hwpoison_filter() filtered the error event,
>> -	 *
>> -	 * In both cases, no further processing is required.
>> -	 */
>>   	if (ret == -EHWPOISON || ret == -EOPNOTSUPP)
>>   		return;
>>   
>> diff --git a/mm/memory-failure.c b/mm/memory-failure.c
>> index 96ce31e5a203..1c5098f32d48 100644
>> --- a/mm/memory-failure.c
>> +++ b/mm/memory-failure.c
>> @@ -2209,9 +2209,12 @@ static void kill_procs_now(struct page *p, unsigned long pfn, int flags,
>>    * Must run in process context (e.g. a work queue) with interrupts
>>    * enabled and no spinlocks held.
>>    *
>> - * Return: 0 for successfully handled the memory error,
>> - *         -EOPNOTSUPP for hwpoison_filter() filtered the error event,
>> - *         < 0(except -EOPNOTSUPP) on failure.
>> + * Return:
>> + *   0             - success,
> 
> One more obvious one from this function:
> 
> 	-ENXIO        - memory not managed by the kernel

Yes, will fix it.

> 
>> + *   -EOPNOTSUPP   - hwpoison_filter() filtered the error event,
>> + *   -EHWPOISON    - the page was already poisoned, potentially
>> + *                   kill process,
>> + *   other negative values - failure.
>>    */
>>   int memory_failure(unsigned long pfn, int flags)
>>   {
>> -- 
> 
> Reviewed-by: Yazen Ghannam <yazen.ghannam@....com>
> 
> Thanks,
> Yazen

Thank you for valuable comments.
Shuai