Subject: Re: [PATCH v4 25/34] m68k: Convert various functions to use ptdescs

From: Mike Rapoport <[email-masked]>
Date: Wed, 14 Jun 2023 18:12:49 +0300

On Mon, Jun 12, 2023 at 02:04:14PM -0700, Vishal Moola (Oracle) wrote:
> As part of the conversions to replace pgtable constructor/destructors with
> ptdesc equivalents, convert various page table functions to use ptdescs.
> 
> Some of the functions use the *get*page*() helper functions. Convert
> these to use pagetable_alloc() and ptdesc_address() instead to help
> standardize page tables further.
> 
> Signed-off-by: Vishal Moola (Oracle) <[email-masked]>

Acked-by: Mike Rapoport (IBM) <[email-masked]>

One comment below
> ---
>  arch/m68k/include/asm/mcf_pgalloc.h  | 41 ++++++++++++++--------------
>  arch/m68k/include/asm/sun3_pgalloc.h |  8 +++---
>  arch/m68k/mm/motorola.c              |  4 +--
>  3 files changed, 27 insertions(+), 26 deletions(-)
> 
> diff --git a/arch/m68k/include/asm/mcf_pgalloc.h b/arch/m68k/include/asm/mcf_pgalloc.h
> index 5c2c0a864524..857949ac9431 100644
> --- a/arch/m68k/include/asm/mcf_pgalloc.h
> +++ b/arch/m68k/include/asm/mcf_pgalloc.h
> @@ -7,20 +7,19 @@
>  
>  extern inline void pte_free_kernel(struct mm_struct *mm, pte_t *pte)
>  {
> -	free_page((unsigned long) pte);
> +	pagetable_free(virt_to_ptdesc(pte));
>  }
>  
>  extern const char bad_pmd_string[];
>  
>  extern inline pte_t *pte_alloc_one_kernel(struct mm_struct *mm)
>  {
> -	unsigned long page = __get_free_page(GFP_DMA);
> +	struct ptdesc *ptdesc = pagetable_alloc(GFP_DMA | __GFP_ZERO, 0);
>  
> -	if (!page)
> +	if (!ptdesc)
>  		return NULL;
>  
> -	memset((void *)page, 0, PAGE_SIZE);
> -	return (pte_t *) (page);
> +	return ptdesc_address(ptdesc);
>  }
>  
>  extern inline pmd_t *pmd_alloc_kernel(pgd_t *pgd, unsigned long address)
> @@ -35,36 +34,36 @@ extern inline pmd_t *pmd_alloc_kernel(pgd_t *pgd, unsigned long address)
>  static inline void __pte_free_tlb(struct mmu_gather *tlb, pgtable_t pgtable,
>  				  unsigned long address)
>  {
> -	struct page *page = virt_to_page(pgtable);
> +	struct ptdesc *ptdesc = virt_to_ptdesc(pgtable);
>  
> -	pgtable_pte_page_dtor(page);
> -	__free_page(page);
> +	pagetable_pte_dtor(ptdesc);
> +	pagetable_free(ptdesc);
>  }
>  
>  static inline pgtable_t pte_alloc_one(struct mm_struct *mm)
>  {
> -	struct page *page = alloc_pages(GFP_DMA, 0);
> +	struct ptdesc *ptdesc = pagetable_alloc(GFP_DMA, 0);

You can add __GFP_ZERO here and drop pagetable_clear() below

>  	pte_t *pte;
>  
> -	if (!page)
> +	if (!ptdesc)
>  		return NULL;
> -	if (!pgtable_pte_page_ctor(page)) {
> -		__free_page(page);
> +	if (!pagetable_pte_ctor(ptdesc)) {
> +		pagetable_free(ptdesc);
>  		return NULL;
>  	}
>  
> -	pte = page_address(page);
> -	clear_page(pte);
> +	pte = ptdesc_address(ptdesc);
> +	pagetable_clear(pte);
>  
>  	return pte;
>  }
>  
>  static inline void pte_free(struct mm_struct *mm, pgtable_t pgtable)
>  {
> -	struct page *page = virt_to_page(pgtable);
> +	struct ptdesc *ptdesc = virt_to_ptdesc(pgtable);
>  
> -	pgtable_pte_page_dtor(page);
> -	__free_page(page);
> +	pagetable_pte_dtor(ptdesc);
> +	pagetable_free(ptdesc);
>  }
>  
>  /*
> @@ -75,16 +74,18 @@ static inline void pte_free(struct mm_struct *mm, pgtable_t pgtable)
>  
>  static inline void pgd_free(struct mm_struct *mm, pgd_t *pgd)
>  {
> -	free_page((unsigned long) pgd);
> +	pagetable_free(virt_to_ptdesc(pgd));
>  }
>  
>  static inline pgd_t *pgd_alloc(struct mm_struct *mm)
>  {
>  	pgd_t *new_pgd;
> +	struct ptdesc *ptdesc = pagetable_alloc(GFP_DMA | GFP_NOWARN, 0);
>  
> -	new_pgd = (pgd_t *)__get_free_page(GFP_DMA | __GFP_NOWARN);
> -	if (!new_pgd)
> +	if (!ptdesc)
>  		return NULL;
> +	new_pgd = ptdesc_address(ptdesc);
> +
>  	memcpy(new_pgd, swapper_pg_dir, PTRS_PER_PGD * sizeof(pgd_t));
>  	memset(new_pgd, 0, PAGE_OFFSET >> PGDIR_SHIFT);
>  	return new_pgd;
> diff --git a/arch/m68k/include/asm/sun3_pgalloc.h b/arch/m68k/include/asm/sun3_pgalloc.h
> index 198036aff519..ff48573db2c0 100644
> --- a/arch/m68k/include/asm/sun3_pgalloc.h
> +++ b/arch/m68k/include/asm/sun3_pgalloc.h
> @@ -17,10 +17,10 @@
>  
>  extern const char bad_pmd_string[];
>  
> -#define __pte_free_tlb(tlb,pte,addr)			\
> -do {							\
> -	pgtable_pte_page_dtor(pte);			\
> -	tlb_remove_page((tlb), pte);			\
> +#define __pte_free_tlb(tlb, pte, addr)				\
> +do {								\
> +	pagetable_pte_dtor(page_ptdesc(pte));			\
> +	tlb_remove_page_ptdesc((tlb), page_ptdesc(pte));	\
>  } while (0)
>  
>  static inline void pmd_populate_kernel(struct mm_struct *mm, pmd_t *pmd, pte_t *pte)
> diff --git a/arch/m68k/mm/motorola.c b/arch/m68k/mm/motorola.c
> index c75984e2d86b..594575a0780c 100644
> --- a/arch/m68k/mm/motorola.c
> +++ b/arch/m68k/mm/motorola.c
> @@ -161,7 +161,7 @@ void *get_pointer_table(int type)
>  			 * m68k doesn't have SPLIT_PTE_PTLOCKS for not having
>  			 * SMP.
>  			 */
> -			pgtable_pte_page_ctor(virt_to_page(page));
> +			pagetable_pte_ctor(virt_to_ptdesc(page));
>  		}
>  
>  		mmu_page_ctor(page);
> @@ -201,7 +201,7 @@ int free_pointer_table(void *table, int type)
>  		list_del(dp);
>  		mmu_page_dtor((void *)page);
>  		if (type == TABLE_PTE)
> -			pgtable_pte_page_dtor(virt_to_page((void *)page));
> +			pagetable_pte_dtor(virt_to_ptdesc((void *)page));
>  		free_page (page);
>  		return 1;
>  	} else if (ptable_list[type].next != dp) {
> -- 
> 2.40.1
> 
> 

-- 
Sincerely yours,
Mike.

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