[v16,2/3] mm: memory-failure: move return value documentation to function declaration

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>
Reviewed-by: Jarkko Sakkinen <jarkko@kernel.org>
Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
---
 arch/x86/kernel/cpu/mce/core.c | 7 -------
 mm/memory-failure.c            | 9 ++++++---
 2 files changed, 6 insertions(+), 10 deletions(-)

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@linux.alibaba.com>
> Reviewed-by: Jarkko Sakkinen <jarkko@kernel.org>
> Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.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

> + *   -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@amd.com>

Thanks,
Yazen

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@linux.alibaba.com>
>> Reviewed-by: Jarkko Sakkinen <jarkko@kernel.org>
>> Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.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@amd.com>
> 
> Thanks,
> Yazen

Thank you for valuable comments.
Shuai