Re: [PATCH v4 17/34] s390: Convert various pgalloc functions to use ptdescs

[Mike Rapoport <rppt@kernel.org>]

On Mon, Jun 12, 2023 at 02:04:06PM -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) <vishal.moola@gmail.com>

Acked-by: Mike Rapoport (IBM) <rppt@kernel.org>

> ---
>  arch/s390/include/asm/pgalloc.h |   4 +-
>  arch/s390/include/asm/tlb.h     |   4 +-
>  arch/s390/mm/pgalloc.c          | 108 ++++++++++++++++----------------
>  3 files changed, 59 insertions(+), 57 deletions(-)
> 
> diff --git a/arch/s390/include/asm/pgalloc.h b/arch/s390/include/asm/pgalloc.h
> index 17eb618f1348..00ad9b88fda9 100644
> --- a/arch/s390/include/asm/pgalloc.h
> +++ b/arch/s390/include/asm/pgalloc.h
> @@ -86,7 +86,7 @@ static inline pmd_t *pmd_alloc_one(struct mm_struct *mm, unsigned long vmaddr)
>  	if (!table)
>  		return NULL;
>  	crst_table_init(table, _SEGMENT_ENTRY_EMPTY);
> -	if (!pgtable_pmd_page_ctor(virt_to_page(table))) {
> +	if (!pagetable_pmd_ctor(virt_to_ptdesc(table))) {
>  		crst_table_free(mm, table);
>  		return NULL;
>  	}
> @@ -97,7 +97,7 @@ static inline void pmd_free(struct mm_struct *mm, pmd_t *pmd)
>  {
>  	if (mm_pmd_folded(mm))
>  		return;
> -	pgtable_pmd_page_dtor(virt_to_page(pmd));
> +	pagetable_pmd_dtor(virt_to_ptdesc(pmd));
>  	crst_table_free(mm, (unsigned long *) pmd);
>  }
>  
> diff --git a/arch/s390/include/asm/tlb.h b/arch/s390/include/asm/tlb.h
> index b91f4a9b044c..383b1f91442c 100644
> --- a/arch/s390/include/asm/tlb.h
> +++ b/arch/s390/include/asm/tlb.h
> @@ -89,12 +89,12 @@ static inline void pmd_free_tlb(struct mmu_gather *tlb, pmd_t *pmd,
>  {
>  	if (mm_pmd_folded(tlb->mm))
>  		return;
> -	pgtable_pmd_page_dtor(virt_to_page(pmd));
> +	pagetable_pmd_dtor(virt_to_ptdesc(pmd));
>  	__tlb_adjust_range(tlb, address, PAGE_SIZE);
>  	tlb->mm->context.flush_mm = 1;
>  	tlb->freed_tables = 1;
>  	tlb->cleared_puds = 1;
> -	tlb_remove_table(tlb, pmd);
> +	tlb_remove_ptdesc(tlb, pmd);
>  }
>  
>  /*
> diff --git a/arch/s390/mm/pgalloc.c b/arch/s390/mm/pgalloc.c
> index 6b99932abc66..eeb7c95b98cf 100644
> --- a/arch/s390/mm/pgalloc.c
> +++ b/arch/s390/mm/pgalloc.c
> @@ -43,17 +43,17 @@ __initcall(page_table_register_sysctl);
>  
>  unsigned long *crst_table_alloc(struct mm_struct *mm)
>  {
> -	struct page *page = alloc_pages(GFP_KERNEL, CRST_ALLOC_ORDER);
> +	struct ptdesc *ptdesc = pagetable_alloc(GFP_KERNEL, CRST_ALLOC_ORDER);
>  
> -	if (!page)
> +	if (!ptdesc)
>  		return NULL;
> -	arch_set_page_dat(page, CRST_ALLOC_ORDER);
> -	return (unsigned long *) page_to_virt(page);
> +	arch_set_page_dat(ptdesc_page(ptdesc), CRST_ALLOC_ORDER);
> +	return (unsigned long *) ptdesc_to_virt(ptdesc);
>  }
>  
>  void crst_table_free(struct mm_struct *mm, unsigned long *table)
>  {
> -	free_pages((unsigned long)table, CRST_ALLOC_ORDER);
> +	pagetable_free(virt_to_ptdesc(table));
>  }
>  
>  static void __crst_table_upgrade(void *arg)
> @@ -140,21 +140,21 @@ static inline unsigned int atomic_xor_bits(atomic_t *v, unsigned int bits)
>  
>  struct page *page_table_alloc_pgste(struct mm_struct *mm)
>  {
> -	struct page *page;
> +	struct ptdesc *ptdesc;
>  	u64 *table;
>  
> -	page = alloc_page(GFP_KERNEL);
> -	if (page) {
> -		table = (u64 *)page_to_virt(page);
> +	ptdesc = pagetable_alloc(GFP_KERNEL, 0);
> +	if (ptdesc) {
> +		table = (u64 *)ptdesc_to_virt(ptdesc);
>  		memset64(table, _PAGE_INVALID, PTRS_PER_PTE);
>  		memset64(table + PTRS_PER_PTE, 0, PTRS_PER_PTE);
>  	}
> -	return page;
> +	return ptdesc_page(ptdesc);
>  }
>  
>  void page_table_free_pgste(struct page *page)
>  {
> -	__free_page(page);
> +	pagetable_free(page_ptdesc(page));
>  }
>  
>  #endif /* CONFIG_PGSTE */
> @@ -230,7 +230,7 @@ void page_table_free_pgste(struct page *page)
>  unsigned long *page_table_alloc(struct mm_struct *mm)
>  {
>  	unsigned long *table;
> -	struct page *page;
> +	struct ptdesc *ptdesc;
>  	unsigned int mask, bit;
>  
>  	/* Try to get a fragment of a 4K page as a 2K page table */
> @@ -238,9 +238,9 @@ unsigned long *page_table_alloc(struct mm_struct *mm)
>  		table = NULL;
>  		spin_lock_bh(&mm->context.lock);
>  		if (!list_empty(&mm->context.pgtable_list)) {
> -			page = list_first_entry(&mm->context.pgtable_list,
> -						struct page, lru);
> -			mask = atomic_read(&page->pt_frag_refcount);
> +			ptdesc = list_first_entry(&mm->context.pgtable_list,
> +						struct ptdesc, pt_list);
> +			mask = atomic_read(&ptdesc->pt_frag_refcount);
>  			/*
>  			 * The pending removal bits must also be checked.
>  			 * Failure to do so might lead to an impossible
> @@ -253,13 +253,13 @@ unsigned long *page_table_alloc(struct mm_struct *mm)
>  			 */
>  			mask = (mask | (mask >> 4)) & 0x03U;
>  			if (mask != 0x03U) {
> -				table = (unsigned long *) page_to_virt(page);
> +				table = (unsigned long *) ptdesc_to_virt(ptdesc);
>  				bit = mask & 1;		/* =1 -> second 2K */
>  				if (bit)
>  					table += PTRS_PER_PTE;
> -				atomic_xor_bits(&page->pt_frag_refcount,
> +				atomic_xor_bits(&ptdesc->pt_frag_refcount,
>  							0x01U << bit);
> -				list_del(&page->lru);
> +				list_del(&ptdesc->pt_list);
>  			}
>  		}
>  		spin_unlock_bh(&mm->context.lock);
> @@ -267,27 +267,27 @@ unsigned long *page_table_alloc(struct mm_struct *mm)
>  			return table;
>  	}
>  	/* Allocate a fresh page */
> -	page = alloc_page(GFP_KERNEL);
> -	if (!page)
> +	ptdesc = pagetable_alloc(GFP_KERNEL, 0);
> +	if (!ptdesc)
>  		return NULL;
> -	if (!pgtable_pte_page_ctor(page)) {
> -		__free_page(page);
> +	if (!pagetable_pte_ctor(ptdesc)) {
> +		pagetable_free(ptdesc);
>  		return NULL;
>  	}
> -	arch_set_page_dat(page, 0);
> +	arch_set_page_dat(ptdesc_page(ptdesc), 0);
>  	/* Initialize page table */
> -	table = (unsigned long *) page_to_virt(page);
> +	table = (unsigned long *) ptdesc_to_virt(ptdesc);
>  	if (mm_alloc_pgste(mm)) {
>  		/* Return 4K page table with PGSTEs */
> -		atomic_xor_bits(&page->pt_frag_refcount, 0x03U);
> +		atomic_xor_bits(&ptdesc->pt_frag_refcount, 0x03U);
>  		memset64((u64 *)table, _PAGE_INVALID, PTRS_PER_PTE);
>  		memset64((u64 *)table + PTRS_PER_PTE, 0, PTRS_PER_PTE);
>  	} else {
>  		/* Return the first 2K fragment of the page */
> -		atomic_xor_bits(&page->pt_frag_refcount, 0x01U);
> +		atomic_xor_bits(&ptdesc->pt_frag_refcount, 0x01U);
>  		memset64((u64 *)table, _PAGE_INVALID, 2 * PTRS_PER_PTE);
>  		spin_lock_bh(&mm->context.lock);
> -		list_add(&page->lru, &mm->context.pgtable_list);
> +		list_add(&ptdesc->pt_list, &mm->context.pgtable_list);
>  		spin_unlock_bh(&mm->context.lock);
>  	}
>  	return table;
> @@ -309,9 +309,8 @@ static void page_table_release_check(struct page *page, void *table,
>  void page_table_free(struct mm_struct *mm, unsigned long *table)
>  {
>  	unsigned int mask, bit, half;
> -	struct page *page;
> +	struct ptdesc *ptdesc = virt_to_ptdesc(table);
>  
> -	page = virt_to_page(table);
>  	if (!mm_alloc_pgste(mm)) {
>  		/* Free 2K page table fragment of a 4K page */
>  		bit = ((unsigned long) table & ~PAGE_MASK)/(PTRS_PER_PTE*sizeof(pte_t));
> @@ -321,39 +320,38 @@ void page_table_free(struct mm_struct *mm, unsigned long *table)
>  		 * will happen outside of the critical section from this
>  		 * function or from __tlb_remove_table()
>  		 */
> -		mask = atomic_xor_bits(&page->pt_frag_refcount, 0x11U << bit);
> +		mask = atomic_xor_bits(&ptdesc->pt_frag_refcount, 0x11U << bit);
>  		if (mask & 0x03U)
> -			list_add(&page->lru, &mm->context.pgtable_list);
> +			list_add(&ptdesc->pt_list, &mm->context.pgtable_list);
>  		else
> -			list_del(&page->lru);
> +			list_del(&ptdesc->pt_list);
>  		spin_unlock_bh(&mm->context.lock);
> -		mask = atomic_xor_bits(&page->pt_frag_refcount, 0x10U << bit);
> +		mask = atomic_xor_bits(&ptdesc->pt_frag_refcount, 0x10U << bit);
>  		if (mask != 0x00U)
>  			return;
>  		half = 0x01U << bit;
>  	} else {
>  		half = 0x03U;
> -		mask = atomic_xor_bits(&page->pt_frag_refcount, 0x03U);
> +		mask = atomic_xor_bits(&ptdesc->pt_frag_refcount, 0x03U);
>  	}
>  
> -	page_table_release_check(page, table, half, mask);
> -	pgtable_pte_page_dtor(page);
> -	__free_page(page);
> +	page_table_release_check(ptdesc_page(ptdesc), table, half, mask);
> +	pagetable_pte_dtor(ptdesc);
> +	pagetable_free(ptdesc);
>  }
>  
>  void page_table_free_rcu(struct mmu_gather *tlb, unsigned long *table,
>  			 unsigned long vmaddr)
>  {
>  	struct mm_struct *mm;
> -	struct page *page;
>  	unsigned int bit, mask;
> +	struct ptdesc *ptdesc = virt_to_ptdesc(table);
>  
>  	mm = tlb->mm;
> -	page = virt_to_page(table);
>  	if (mm_alloc_pgste(mm)) {
>  		gmap_unlink(mm, table, vmaddr);
>  		table = (unsigned long *) ((unsigned long)table | 0x03U);
> -		tlb_remove_table(tlb, table);
> +		tlb_remove_ptdesc(tlb, table);
>  		return;
>  	}
>  	bit = ((unsigned long) table & ~PAGE_MASK) / (PTRS_PER_PTE*sizeof(pte_t));
> @@ -363,11 +361,11 @@ void page_table_free_rcu(struct mmu_gather *tlb, unsigned long *table,
>  	 * outside of the critical section from __tlb_remove_table() or from
>  	 * page_table_free()
>  	 */
> -	mask = atomic_xor_bits(&page->pt_frag_refcount, 0x11U << bit);
> +	mask = atomic_xor_bits(&ptdesc->pt_frag_refcount, 0x11U << bit);
>  	if (mask & 0x03U)
> -		list_add_tail(&page->lru, &mm->context.pgtable_list);
> +		list_add_tail(&ptdesc->pt_list, &mm->context.pgtable_list);
>  	else
> -		list_del(&page->lru);
> +		list_del(&ptdesc->pt_list);
>  	spin_unlock_bh(&mm->context.lock);
>  	table = (unsigned long *) ((unsigned long) table | (0x01U << bit));
>  	tlb_remove_table(tlb, table);
> @@ -377,7 +375,7 @@ void __tlb_remove_table(void *_table)
>  {
>  	unsigned int mask = (unsigned long) _table & 0x03U, half = mask;
>  	void *table = (void *)((unsigned long) _table ^ mask);
> -	struct page *page = virt_to_page(table);
> +	struct ptdesc *ptdesc = virt_to_ptdesc(table);
>  
>  	switch (half) {
>  	case 0x00U:	/* pmd, pud, or p4d */
> @@ -385,18 +383,18 @@ void __tlb_remove_table(void *_table)
>  		return;
>  	case 0x01U:	/* lower 2K of a 4K page table */
>  	case 0x02U:	/* higher 2K of a 4K page table */
> -		mask = atomic_xor_bits(&page->pt_frag_refcount, mask << 4);
> +		mask = atomic_xor_bits(&ptdesc->pt_frag_refcount, mask << 4);
>  		if (mask != 0x00U)
>  			return;
>  		break;
>  	case 0x03U:	/* 4K page table with pgstes */
> -		mask = atomic_xor_bits(&page->pt_frag_refcount, 0x03U);
> +		mask = atomic_xor_bits(&ptdesc->pt_frag_refcount, 0x03U);
>  		break;
>  	}
>  
> -	page_table_release_check(page, table, half, mask);
> -	pgtable_pte_page_dtor(page);
> -	__free_page(page);
> +	page_table_release_check(ptdesc_page(ptdesc), table, half, mask);
> +	pagetable_pte_dtor(ptdesc);
> +	pagetable_free(ptdesc);
>  }
>  
>  /*
> @@ -424,16 +422,20 @@ static void base_pgt_free(unsigned long *table)
>  static unsigned long *base_crst_alloc(unsigned long val)
>  {
>  	unsigned long *table;
> +	struct ptdesc *ptdesc;
>  
> -	table =	(unsigned long *)__get_free_pages(GFP_KERNEL, CRST_ALLOC_ORDER);
> -	if (table)
> -		crst_table_init(table, val);
> +	ptdesc = pagetable_alloc(GFP_KERNEL, CRST_ALLOC_ORDER);
> +	if (!ptdesc)
> +		return NULL;
> +	table = ptdesc_address(ptdesc);
> +
> +	crst_table_init(table, val);
>  	return table;
>  }
>  
>  static void base_crst_free(unsigned long *table)
>  {
> -	free_pages((unsigned long)table, CRST_ALLOC_ORDER);
> +	pagetable_free(virt_to_ptdesc(table));
>  }
>  
>  #define BASE_ADDR_END_FUNC(NAME, SIZE)					\
> -- 
> 2.40.1
> 
> 

-- 
Sincerely yours,
Mike.