diff mbox series

[RFC,-next,V2,2/7] arm64: fix page_address return value in copy_highpage

Message ID 20220406091311.3354723-3-tongtiangen@huawei.com (mailing list archive)
State New, archived
Headers show
Series arm64: add machine check safe support | expand

Commit Message

Tong Tiangen April 6, 2022, 9:13 a.m. UTC
Function page_address return void, fix it.

Signed-off-by: Tong Tiangen <tongtiangen@huawei.com>
---
 arch/arm64/mm/copypage.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

Comments

Mark Rutland April 6, 2022, 10:22 a.m. UTC | #1
On Wed, Apr 06, 2022 at 09:13:06AM +0000, Tong Tiangen wrote:
> Function page_address return void, fix it.
> 
> Signed-off-by: Tong Tiangen <tongtiangen@huawei.com>

This looks like a sensible cleanup, but the commit title and message aren't
that clear.

Can you please make this:

| arm64: fix types in copy_highpage()
|
| In copy_highpage() the `kto` and `kfrom` local variables are pointers to
| struct page, but these are used to hold arbitrary pointers to kernel memory.
| Each call to page_address() returns a void pointer to memory associated with
| the relevant page, and copy_page() expects void pointers to this memory.
|
| This inconsistency was introduced in commit:
|
|   2563776b41c31908 ("arm64: mte: Tags-aware copy_{user_,}highpage() implementations")
|
| ... and while this doesn't appear to be harmful in practice it is clearly wrong.
|
| Correct this by making `kto` and `kfrom` void pointers.
|
| Fixes: 2563776b41c31908 ("arm64: mte: Tags-aware copy_{user_,}highpage() implementations")

With that:

Acked-by: Mark Rutland <mark.rutland@arm.com>

Thanks,
Mark.

> ---
>  arch/arm64/mm/copypage.c | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/arch/arm64/mm/copypage.c b/arch/arm64/mm/copypage.c
> index b5447e53cd73..0dea80bf6de4 100644
> --- a/arch/arm64/mm/copypage.c
> +++ b/arch/arm64/mm/copypage.c
> @@ -16,8 +16,8 @@
>  
>  void copy_highpage(struct page *to, struct page *from)
>  {
> -	struct page *kto = page_address(to);
> -	struct page *kfrom = page_address(from);
> +	void *kto = page_address(to);
> +	void *kfrom = page_address(from);
>  
>  	copy_page(kto, kfrom);
>  
> -- 
> 2.18.0.huawei.25
> 
> 
> _______________________________________________
> linux-arm-kernel mailing list
> linux-arm-kernel@lists.infradead.org
> http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
Tong Tiangen April 6, 2022, 12:47 p.m. UTC | #2
在 2022/4/6 18:22, Mark Rutland 写道:
> On Wed, Apr 06, 2022 at 09:13:06AM +0000, Tong Tiangen wrote:
>> Function page_address return void, fix it.
>>
>> Signed-off-by: Tong Tiangen <tongtiangen@huawei.com>
> 
> This looks like a sensible cleanup, but the commit title and message aren't
> that clear.
> 
> Can you please make this:
> 
> | arm64: fix types in copy_highpage()
> |
> | In copy_highpage() the `kto` and `kfrom` local variables are pointers to
> | struct page, but these are used to hold arbitrary pointers to kernel memory.
> | Each call to page_address() returns a void pointer to memory associated with
> | the relevant page, and copy_page() expects void pointers to this memory.
> |
> | This inconsistency was introduced in commit:
> |
> |   2563776b41c31908 ("arm64: mte: Tags-aware copy_{user_,}highpage() implementations")
> |
> | ... and while this doesn't appear to be harmful in practice it is clearly wrong.
> |
> | Correct this by making `kto` and `kfrom` void pointers.
> |
> | Fixes: 2563776b41c31908 ("arm64: mte: Tags-aware copy_{user_,}highpage() implementations")
> 
> With that:
> 
> Acked-by: Mark Rutland <mark.rutland@arm.com>
> 
> Thanks,
> Mark.
> 

OK, sure , will do in next version.

Thanks.
Tong.

>> ---
>>   arch/arm64/mm/copypage.c | 4 ++--
>>   1 file changed, 2 insertions(+), 2 deletions(-)
>>
>> diff --git a/arch/arm64/mm/copypage.c b/arch/arm64/mm/copypage.c
>> index b5447e53cd73..0dea80bf6de4 100644
>> --- a/arch/arm64/mm/copypage.c
>> +++ b/arch/arm64/mm/copypage.c
>> @@ -16,8 +16,8 @@
>>   
>>   void copy_highpage(struct page *to, struct page *from)
>>   {
>> -	struct page *kto = page_address(to);
>> -	struct page *kfrom = page_address(from);
>> +	void *kto = page_address(to);
>> +	void *kfrom = page_address(from);
>>   
>>   	copy_page(kto, kfrom);
>>   
>> -- 
>> 2.18.0.huawei.25
>>
>>
>> _______________________________________________
>> linux-arm-kernel mailing list
>> linux-arm-kernel@lists.infradead.org
>> http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
> .
diff mbox series

Patch

diff --git a/arch/arm64/mm/copypage.c b/arch/arm64/mm/copypage.c
index b5447e53cd73..0dea80bf6de4 100644
--- a/arch/arm64/mm/copypage.c
+++ b/arch/arm64/mm/copypage.c
@@ -16,8 +16,8 @@ 
 
 void copy_highpage(struct page *to, struct page *from)
 {
-	struct page *kto = page_address(to);
-	struct page *kfrom = page_address(from);
+	void *kto = page_address(to);
+	void *kfrom = page_address(from);
 
 	copy_page(kto, kfrom);