Re: [PATCH 2/6] mm: change to return bool for ptep_clear_flush_young()/clear_flush_young_ptes()

On Thu, Mar 19, 2026 at 11:24:01AM +0800, Baolin Wang wrote:
> The ptep_clear_flush_young() and clear_flush_young_ptes() are used to clear
> the young flag and flush the TLB, returning whether the young flag was set.
> Change the return type to bool to make the intention clearer.
>
> Signed-off-by: Baolin Wang <[email protected]>

Couple nits but LGTM, so:

Reviewed-by: Lorenzo Stoakes (Oracle) <[email protected]>

> ---
>  arch/arm64/include/asm/pgtable.h             | 15 +++++++--------
>  arch/arm64/mm/contpte.c                      |  4 ++--
>  arch/parisc/include/asm/pgtable.h            |  2 +-
>  arch/parisc/kernel/cache.c                   |  8 ++++----
>  arch/powerpc/include/asm/nohash/64/pgtable.h |  2 +-
>  arch/riscv/include/asm/pgtable.h             |  4 ++--
>  arch/s390/include/asm/pgtable.h              |  4 ++--
>  arch/x86/include/asm/pgtable.h               |  4 ++--
>  arch/x86/mm/pgtable.c                        |  4 ++--
>  include/linux/pgtable.h                      |  8 ++++----
>  mm/pgtable-generic.c                         |  7 ++++---
>  11 files changed, 31 insertions(+), 31 deletions(-)
>
> diff --git a/arch/arm64/include/asm/pgtable.h b/arch/arm64/include/asm/pgtable.h
> index 8c651695204c..393a9d1873f6 100644
> --- a/arch/arm64/include/asm/pgtable.h
> +++ b/arch/arm64/include/asm/pgtable.h
> @@ -1299,10 +1299,10 @@ static inline bool __ptep_test_and_clear_young(struct vm_area_struct *vma,
>  	return pte_young(pte);
>  }
>
> -static inline int __ptep_clear_flush_young(struct vm_area_struct *vma,
> -					 unsigned long address, pte_t *ptep)
> +static inline bool __ptep_clear_flush_young(struct vm_area_struct *vma,
> +					    unsigned long address, pte_t *ptep)

I mean this is subjective stuff but can we just put 2nd line 2 tabs indented
underneath? Makes it easier for changes like this to not propagate.

Same comment for all of these!

>  {
> -	int young = __ptep_test_and_clear_young(vma, address, ptep);
> +	bool young = __ptep_test_and_clear_young(vma, address, ptep);
>
>  	if (young) {
>  		/*
> @@ -1648,7 +1648,7 @@ extern pte_t contpte_get_and_clear_full_ptes(struct mm_struct *mm,
>  				unsigned int nr, int full);
>  bool contpte_test_and_clear_young_ptes(struct vm_area_struct *vma,
>  				unsigned long addr, pte_t *ptep, unsigned int nr);
> -int contpte_clear_flush_young_ptes(struct vm_area_struct *vma,
> +bool contpte_clear_flush_young_ptes(struct vm_area_struct *vma,
>  				unsigned long addr, pte_t *ptep, unsigned int nr);
>  extern void contpte_wrprotect_ptes(struct mm_struct *mm, unsigned long addr,
>  				pte_t *ptep, unsigned int nr);
> @@ -1831,7 +1831,7 @@ static inline bool ptep_test_and_clear_young(struct vm_area_struct *vma,
>  }
>
>  #define __HAVE_ARCH_PTEP_CLEAR_YOUNG_FLUSH
> -static inline int ptep_clear_flush_young(struct vm_area_struct *vma,
> +static inline bool ptep_clear_flush_young(struct vm_area_struct *vma,
>  				unsigned long addr, pte_t *ptep)
>  {
>  	pte_t orig_pte = __ptep_get(ptep);
> @@ -1843,9 +1843,8 @@ static inline int ptep_clear_flush_young(struct vm_area_struct *vma,
>  }
>
>  #define clear_flush_young_ptes clear_flush_young_ptes
> -static inline int clear_flush_young_ptes(struct vm_area_struct *vma,
> -					 unsigned long addr, pte_t *ptep,
> -					 unsigned int nr)
> +static inline bool clear_flush_young_ptes(struct vm_area_struct *vma,
> +				unsigned long addr, pte_t *ptep, unsigned int nr)
>  {
>  	if (likely(nr == 1 && !pte_cont(__ptep_get(ptep))))
>  		return __ptep_clear_flush_young(vma, addr, ptep);
> diff --git a/arch/arm64/mm/contpte.c b/arch/arm64/mm/contpte.c
> index 0b88278927a4..2ef4bff3b998 100644
> --- a/arch/arm64/mm/contpte.c
> +++ b/arch/arm64/mm/contpte.c
> @@ -535,11 +535,11 @@ bool contpte_test_and_clear_young_ptes(struct vm_area_struct *vma,
>  }
>  EXPORT_SYMBOL_GPL(contpte_test_and_clear_young_ptes);
>
> -int contpte_clear_flush_young_ptes(struct vm_area_struct *vma,
> +bool contpte_clear_flush_young_ptes(struct vm_area_struct *vma,
>  				unsigned long addr, pte_t *ptep,
>  				unsigned int nr)
>  {
> -	int young;
> +	bool young;
>
>  	young = contpte_test_and_clear_young_ptes(vma, addr, ptep, nr);
>
> diff --git a/arch/parisc/include/asm/pgtable.h b/arch/parisc/include/asm/pgtable.h
> index d5e39f2eb415..f6984b3ba531 100644
> --- a/arch/parisc/include/asm/pgtable.h
> +++ b/arch/parisc/include/asm/pgtable.h
> @@ -450,7 +450,7 @@ static inline bool ptep_test_and_clear_young(struct vm_area_struct *vma, unsigne
>  	return true;
>  }
>
> -int ptep_clear_flush_young(struct vm_area_struct *vma, unsigned long addr, pte_t *ptep);
> +bool ptep_clear_flush_young(struct vm_area_struct *vma, unsigned long addr, pte_t *ptep);
>  pte_t ptep_clear_flush(struct vm_area_struct *vma, unsigned long addr, pte_t *ptep);
>
>  struct mm_struct;
> diff --git a/arch/parisc/kernel/cache.c b/arch/parisc/kernel/cache.c
> index 4c5240d3a3c7..268530eb107d 100644
> --- a/arch/parisc/kernel/cache.c
> +++ b/arch/parisc/kernel/cache.c
> @@ -781,18 +781,18 @@ void flush_anon_page(struct vm_area_struct *vma, struct page *page, unsigned lon
>  	__flush_cache_page(vma, vmaddr, PFN_PHYS(page_to_pfn(page)));
>  }
>
> -int ptep_clear_flush_young(struct vm_area_struct *vma, unsigned long addr,
> -			   pte_t *ptep)
> +bool ptep_clear_flush_young(struct vm_area_struct *vma, unsigned long addr,
> +			    pte_t *ptep)
>  {
>  	pte_t pte = ptep_get(ptep);
>
>  	if (!pte_young(pte))
> -		return 0;
> +		return false;
>  	set_pte(ptep, pte_mkold(pte));
>  #if CONFIG_FLUSH_PAGE_ACCESSED
>  	__flush_cache_page(vma, addr, PFN_PHYS(pte_pfn(pte)));
>  #endif
> -	return 1;
> +	return true;
>  }
>
>  /*
> diff --git a/arch/powerpc/include/asm/nohash/64/pgtable.h b/arch/powerpc/include/asm/nohash/64/pgtable.h
> index 2deb955b7bc8..661eb3820d12 100644
> --- a/arch/powerpc/include/asm/nohash/64/pgtable.h
> +++ b/arch/powerpc/include/asm/nohash/64/pgtable.h
> @@ -155,7 +155,7 @@ static inline void huge_ptep_set_wrprotect(struct mm_struct *mm,
>  #define __HAVE_ARCH_PTEP_CLEAR_YOUNG_FLUSH
>  #define ptep_clear_flush_young(__vma, __address, __ptep)		\
>  ({									\
> -	int __young = ptep_test_and_clear_young(__vma, __address, __ptep);\
> +	bool __young = ptep_test_and_clear_young(__vma, __address, __ptep);\
>  	__young;							\
>  })
>
> diff --git a/arch/riscv/include/asm/pgtable.h b/arch/riscv/include/asm/pgtable.h
> index fb010dcdf343..11f57ccf6dc9 100644
> --- a/arch/riscv/include/asm/pgtable.h
> +++ b/arch/riscv/include/asm/pgtable.h
> @@ -695,8 +695,8 @@ static inline void ptep_set_wrprotect(struct mm_struct *mm,
>  }
>
>  #define __HAVE_ARCH_PTEP_CLEAR_YOUNG_FLUSH
> -static inline int ptep_clear_flush_young(struct vm_area_struct *vma,
> -					 unsigned long address, pte_t *ptep)
> +static inline bool ptep_clear_flush_young(struct vm_area_struct *vma,
> +					  unsigned long address, pte_t *ptep)
>  {
>  	/*
>  	 * This comment is borrowed from x86, but applies equally to RISC-V:
> diff --git a/arch/s390/include/asm/pgtable.h b/arch/s390/include/asm/pgtable.h
> index da1a7a31fa22..c9ab81caaf75 100644
> --- a/arch/s390/include/asm/pgtable.h
> +++ b/arch/s390/include/asm/pgtable.h
> @@ -1174,8 +1174,8 @@ static inline bool ptep_test_and_clear_young(struct vm_area_struct *vma,
>  }
>
>  #define __HAVE_ARCH_PTEP_CLEAR_YOUNG_FLUSH
> -static inline int ptep_clear_flush_young(struct vm_area_struct *vma,
> -					 unsigned long address, pte_t *ptep)
> +static inline bool ptep_clear_flush_young(struct vm_area_struct *vma,
> +					  unsigned long address, pte_t *ptep)
>  {
>  	return ptep_test_and_clear_young(vma, address, ptep);
>  }
> diff --git a/arch/x86/include/asm/pgtable.h b/arch/x86/include/asm/pgtable.h
> index 563a6289ea44..554dea93eb99 100644
> --- a/arch/x86/include/asm/pgtable.h
> +++ b/arch/x86/include/asm/pgtable.h
> @@ -1236,8 +1236,8 @@ extern bool ptep_test_and_clear_young(struct vm_area_struct *vma,
>  				      unsigned long addr, pte_t *ptep);
>
>  #define __HAVE_ARCH_PTEP_CLEAR_YOUNG_FLUSH
> -extern int ptep_clear_flush_young(struct vm_area_struct *vma,
> -				  unsigned long address, pte_t *ptep);
> +extern bool ptep_clear_flush_young(struct vm_area_struct *vma,
> +				   unsigned long address, pte_t *ptep);

Drop extern please!

>
>  #define __HAVE_ARCH_PTEP_GET_AND_CLEAR
>  static inline pte_t ptep_get_and_clear(struct mm_struct *mm, unsigned long addr,
> diff --git a/arch/x86/mm/pgtable.c b/arch/x86/mm/pgtable.c
> index c594976afc5c..0007dc3d739e 100644
> --- a/arch/x86/mm/pgtable.c
> +++ b/arch/x86/mm/pgtable.c
> @@ -483,8 +483,8 @@ int pudp_test_and_clear_young(struct vm_area_struct *vma,
>  }
>  #endif
>
> -int ptep_clear_flush_young(struct vm_area_struct *vma,
> -			   unsigned long address, pte_t *ptep)
> +bool ptep_clear_flush_young(struct vm_area_struct *vma,
> +			    unsigned long address, pte_t *ptep)
>  {
>  	/*
>  	 * On x86 CPUs, clearing the accessed bit without a TLB flush
> diff --git a/include/linux/pgtable.h b/include/linux/pgtable.h
> index 8e75dc9f7932..1198e216fde3 100644
> --- a/include/linux/pgtable.h
> +++ b/include/linux/pgtable.h
> @@ -531,8 +531,8 @@ static inline int pmdp_test_and_clear_young(struct vm_area_struct *vma,
>  #endif
>
>  #ifndef __HAVE_ARCH_PTEP_CLEAR_YOUNG_FLUSH
> -int ptep_clear_flush_young(struct vm_area_struct *vma,
> -			   unsigned long address, pte_t *ptep);
> +bool ptep_clear_flush_young(struct vm_area_struct *vma,
> +			    unsigned long address, pte_t *ptep);
>  #endif
>
>  #ifndef __HAVE_ARCH_PMDP_CLEAR_YOUNG_FLUSH
> @@ -1086,10 +1086,10 @@ static inline void wrprotect_ptes(struct mm_struct *mm, unsigned long addr,
>   * Context: The caller holds the page table lock.  The PTEs map consecutive
>   * pages that belong to the same folio.  The PTEs are all in the same PMD.
>   */
> -static inline int clear_flush_young_ptes(struct vm_area_struct *vma,
> +static inline bool clear_flush_young_ptes(struct vm_area_struct *vma,
>  		unsigned long addr, pte_t *ptep, unsigned int nr)
>  {
> -	int young = 0;
> +	bool young = false;
>
>  	for (;;) {
>  		young |= ptep_clear_flush_young(vma, addr, ptep);
> diff --git a/mm/pgtable-generic.c b/mm/pgtable-generic.c
> index af7966169d69..db0ee918b08a 100644
> --- a/mm/pgtable-generic.c
> +++ b/mm/pgtable-generic.c
> @@ -81,10 +81,11 @@ int ptep_set_access_flags(struct vm_area_struct *vma,
>  #endif
>
>  #ifndef __HAVE_ARCH_PTEP_CLEAR_YOUNG_FLUSH
> -int ptep_clear_flush_young(struct vm_area_struct *vma,
> -			   unsigned long address, pte_t *ptep)
> +bool ptep_clear_flush_young(struct vm_area_struct *vma,
> +		unsigned long address, pte_t *ptep)
>  {
> -	int young;
> +	bool young;
> +
>  	young = ptep_test_and_clear_young(vma, address, ptep);
>  	if (young)
>  		flush_tlb_page(vma, address);
> --
> 2.47.3
>