linux-kernel - Re: [PATCH v11 2/3] mm: memory-failure: move return value documentation to function declaration

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Date: Tue, 27 Feb 2024 09:27:57 +0800
From: Shuai Xue <xueshuai@...ux.alibaba.com>
To: Borislav Petkov <bp@...en8.de>
Cc: rafael@...nel.org, wangkefeng.wang@...wei.com, tanxiaofei@...wei.com,
 mawupeng1@...wei.com, tony.luck@...el.com, linmiaohe@...wei.com,
 naoya.horiguchi@....com, james.morse@....com, gregkh@...uxfoundation.org,
 will@...nel.org, jarkko@...nel.org, linux-acpi@...r.kernel.org,
 linux-mm@...ck.org, linux-kernel@...r.kernel.org, akpm@...ux-foundation.org,
 linux-edac@...r.kernel.org, x86@...nel.org, justin.he@....com,
 ardb@...nel.org, ying.huang@...el.com, ashish.kalra@....com,
 baolin.wang@...ux.alibaba.com, tglx@...utronix.de, mingo@...hat.com,
 dave.hansen@...ux.intel.com, lenb@...nel.org, hpa@...or.com,
 robert.moore@...el.com, lvying6@...wei.com, xiexiuqi@...wei.com,
 zhuo.song@...ux.alibaba.com
Subject: Re: [PATCH v11 2/3] mm: memory-failure: move return value
 documentation to function declaration



On 2024/2/26 18:46, Borislav Petkov wrote:
> On Sun, Feb 04, 2024 at 04:01:43PM +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>
>> ---
>>  arch/x86/kernel/cpu/mce/core.c | 9 +--------
>>  mm/memory-failure.c            | 9 ++++++---
>>  2 files changed, 7 insertions(+), 11 deletions(-)
>>
>> diff --git a/arch/x86/kernel/cpu/mce/core.c b/arch/x86/kernel/cpu/mce/core.c
>> index bc39252bc54f..822b21eb48ad 100644
>> --- a/arch/x86/kernel/cpu/mce/core.c
>> +++ b/arch/x86/kernel/cpu/mce/core.c
>> @@ -1365,17 +1365,10 @@ 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;
>>  
>> -	pr_err("Memory error not recovered");
>> +	pr_err("Sending SIGBUS to current task due to memory error not recovered");
> 
> Unrelated change.

Yes, I will drop the error message change.

> 
>>  	kill_me_now(cb);
>>  }
>>  
>> diff --git a/mm/memory-failure.c b/mm/memory-failure.c
>> index 636280d04008..d33729c48eff 100644
>> --- a/mm/memory-failure.c
>> +++ b/mm/memory-failure.c
>> @@ -2175,9 +2175,12 @@ static int memory_failure_dev_pagemap(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 values:
>> + *   0             - success
>> + *   -EOPNOTSUPP   - hwpoison_filter() filtered the error event.
>> + *   -EHWPOISON    - sent SIGBUS to the current process with the proper
>> + *                   error info by kill_accessing_process().
> 
> kill_accessing_process() is not the only one returning -EHWPOISON.
> 
> And if you look at the code, it should be:
> 
> 	-EHWPOISON	- the page was already poisoned, potentially
> 			kill process
> 
> or so.
> 

You are right, will fix it in next version.

Thank you.

Best Regards.
Shuai