Re: [PATCH 4/6] mm: change to return bool for pmdp_clear_flush_young()

[Baolin Wang <baolin.wang@linux.alibaba.com>]

On 3/19/26 7:33 PM, Lorenzo Stoakes (Oracle) wrote:
> On Thu, Mar 19, 2026 at 11:24:03AM +0800, Baolin Wang wrote:
>> The pmdp_clear_flush_young() is used to clear the young flag and flush the
>> TLB, returning whether the young flag was set for this PMD entry. Change
>> the return type to bool to make the intention clearer.
>>
>> Signed-off-by: Baolin Wang <baolin.wang@linux.alibaba.com>
> 
> Some nits, but otherwise LGTM, so:
> 
> Reviewed-by: Lorenzo Stoakes (Oracle) <ljs@kernel.org>
> 
>> ---
>>   arch/s390/include/asm/pgtable.h |  4 ++--
>>   arch/x86/include/asm/pgtable.h  |  4 ++--
>>   arch/x86/mm/pgtable.c           |  6 +++---
>>   include/linux/pgtable.h         | 10 +++++-----
>>   mm/pgtable-generic.c            |  7 ++++---
>>   5 files changed, 16 insertions(+), 15 deletions(-)
>>
>> diff --git a/arch/s390/include/asm/pgtable.h b/arch/s390/include/asm/pgtable.h
>> index 1f5efb7be71d..90bba85ca4b8 100644
>> --- a/arch/s390/include/asm/pgtable.h
>> +++ b/arch/s390/include/asm/pgtable.h
>> @@ -1693,8 +1693,8 @@ static inline bool pmdp_test_and_clear_young(struct vm_area_struct *vma,
>>   }
>>
>>   #define __HAVE_ARCH_PMDP_CLEAR_YOUNG_FLUSH
>> -static inline int pmdp_clear_flush_young(struct vm_area_struct *vma,
>> -					 unsigned long addr, pmd_t *pmdp)
>> +static inline bool pmdp_clear_flush_young(struct vm_area_struct *vma,
>> +					  unsigned long addr, pmd_t *pmdp)
> 
> Same indentation comment as with other patches, 2 tabs you know the drill :)
> applies to all such in this patch.
> 
>>   {
>>   	VM_BUG_ON(addr & ~HPAGE_MASK);
>>   	return pmdp_test_and_clear_young(vma, addr, pmdp);
>> diff --git a/arch/x86/include/asm/pgtable.h b/arch/x86/include/asm/pgtable.h
>> index bd02ee730a23..f9439449c9bd 100644
>> --- a/arch/x86/include/asm/pgtable.h
>> +++ b/arch/x86/include/asm/pgtable.h
>> @@ -1301,8 +1301,8 @@ extern int pudp_test_and_clear_young(struct vm_area_struct *vma,
>>   				     unsigned long addr, pud_t *pudp);
>>
>>   #define __HAVE_ARCH_PMDP_CLEAR_YOUNG_FLUSH
>> -extern int pmdp_clear_flush_young(struct vm_area_struct *vma,
>> -				  unsigned long address, pmd_t *pmdp);
>> +extern bool pmdp_clear_flush_young(struct vm_area_struct *vma,
>> +				   unsigned long address, pmd_t *pmdp);
> 
> Drop the extern please!

Ack.

>>   #define __HAVE_ARCH_PMDP_HUGE_GET_AND_CLEAR
>> diff --git a/arch/x86/mm/pgtable.c b/arch/x86/mm/pgtable.c
>> index 10a5e0b2be36..8c336edf0e65 100644
>> --- a/arch/x86/mm/pgtable.c
>> +++ b/arch/x86/mm/pgtable.c
>> @@ -503,10 +503,10 @@ bool ptep_clear_flush_young(struct vm_area_struct *vma,
>>   }
>>
>>   #ifdef CONFIG_TRANSPARENT_HUGEPAGE
>> -int pmdp_clear_flush_young(struct vm_area_struct *vma,
>> -			   unsigned long address, pmd_t *pmdp)
>> +bool pmdp_clear_flush_young(struct vm_area_struct *vma,
>> +			    unsigned long address, pmd_t *pmdp)
>>   {
>> -	int young;
>> +	bool young;
>>
>>   	VM_BUG_ON(address & ~HPAGE_PMD_MASK);
>>
>> diff --git a/include/linux/pgtable.h b/include/linux/pgtable.h
>> index e53220b0a9a3..8b8838f19af3 100644
>> --- a/include/linux/pgtable.h
>> +++ b/include/linux/pgtable.h
>> @@ -536,18 +536,18 @@ bool ptep_clear_flush_young(struct vm_area_struct *vma,
>>
>>   #ifndef __HAVE_ARCH_PMDP_CLEAR_YOUNG_FLUSH
>>   #ifdef CONFIG_TRANSPARENT_HUGEPAGE
>> -extern int pmdp_clear_flush_young(struct vm_area_struct *vma,
>> -				  unsigned long address, pmd_t *pmdp);
>> +bool pmdp_clear_flush_young(struct vm_area_struct *vma,
>> +		unsigned long address, pmd_t *pmdp);
> 
> Ahh! Here you drop the extern :) AND use 2 tabs :)) thanks!

Right. Because this is the mm subsystem, and I know the maintainers' 
preferences:)