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Message-ID: <76cc249c-31b2-4fd9-a36c-9ec184ffe01c@linux.alibaba.com>
Date: Tue, 27 Feb 2024 09:27:57 +0800
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Subject: Re: [PATCH v11 2/3] mm: memory-failure: move return value
 documentation to function declaration
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To: Borislav Petkov <bp@alien8.de>
Cc: rafael@kernel.org, wangkefeng.wang@huawei.com, tanxiaofei@huawei.com,
 mawupeng1@huawei.com, tony.luck@intel.com, linmiaohe@huawei.com,
 naoya.horiguchi@nec.com, james.morse@arm.com, gregkh@linuxfoundation.org,
 will@kernel.org, jarkko@kernel.org, linux-acpi@vger.kernel.org,
 linux-mm@kvack.org, linux-kernel@vger.kernel.org, akpm@linux-foundation.org,
 linux-edac@vger.kernel.org, x86@kernel.org, justin.he@arm.com,
 ardb@kernel.org, ying.huang@intel.com, ashish.kalra@amd.com,
 baolin.wang@linux.alibaba.com, tglx@linutronix.de, mingo@redhat.com,
 dave.hansen@linux.intel.com, lenb@kernel.org, hpa@zytor.com,
 robert.moore@intel.com, lvying6@huawei.com, xiexiuqi@huawei.com,
 zhuo.song@linux.alibaba.com
References: <20221027042445.60108-1-xueshuai@linux.alibaba.com>
 <20240204080144.7977-3-xueshuai@linux.alibaba.com>
 <20240226104611.GCZdxr82q-Wcms7R3S@fat_crate.local>
From: Shuai Xue <xueshuai@linux.alibaba.com>
In-Reply-To: <20240226104611.GCZdxr82q-Wcms7R3S@fat_crate.local>
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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@linux.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