[PATCH v2 08/19] ARC: mm: switch pgtable_t back to struct page *

From: Vineet Gupta
Date: Thu Aug 12 2021 - 19:38:19 EST


So far ARC pgtable_t has not been struct page based to avoid extra
page_address() calls involved. However the differences are down to
noise and get in the way of using generic code, hence this patch.

Suggested-by: Mike Rapoport <rppt@xxxxxxxxxx>
Signed-off-by: Vineet Gupta <vgupta@xxxxxxxxxx>
---
arch/arc/include/asm/page.h | 2 +-
arch/arc/include/asm/pgalloc.h | 57 ++++++++++------------------------
arch/arc/mm/init.c | 3 ++
3 files changed, 21 insertions(+), 41 deletions(-)

diff --git a/arch/arc/include/asm/page.h b/arch/arc/include/asm/page.h
index c4ac827379cd..514b8b70df50 100644
--- a/arch/arc/include/asm/page.h
+++ b/arch/arc/include/asm/page.h
@@ -58,7 +58,7 @@ typedef struct {

#define pte_pgprot(x) __pgprot(pte_val(x))

-typedef pte_t * pgtable_t;
+typedef struct page *pgtable_t;

/*
* Use virt_to_pfn with caution:
diff --git a/arch/arc/include/asm/pgalloc.h b/arch/arc/include/asm/pgalloc.h
index 408bc4b0842d..8ab1af3da6e7 100644
--- a/arch/arc/include/asm/pgalloc.h
+++ b/arch/arc/include/asm/pgalloc.h
@@ -45,22 +45,17 @@ pmd_populate_kernel(struct mm_struct *mm, pmd_t *pmd, pte_t *pte)
set_pmd(pmd, __pmd((unsigned long)pte));
}

-static inline void pmd_populate(struct mm_struct *mm, pmd_t *pmd, pgtable_t pte)
+static inline void pmd_populate(struct mm_struct *mm, pmd_t *pmd, pgtable_t pte_page)
{
- set_pmd(pmd, __pmd((unsigned long)pte));
-}
-
-static inline int __get_order_pgd(void)
-{
- return get_order(PTRS_PER_PGD * sizeof(pgd_t));
+ set_pmd(pmd, __pmd((unsigned long)page_address(pte_page)));
}

static inline pgd_t *pgd_alloc(struct mm_struct *mm)
{
- int num, num2;
- pgd_t *ret = (pgd_t *) __get_free_pages(GFP_KERNEL, __get_order_pgd());
+ pgd_t *ret = (pgd_t *) __get_free_page(GFP_KERNEL);

if (ret) {
+ int num, num2;
num = USER_PTRS_PER_PGD + USER_KERNEL_GUTTER / PGDIR_SIZE;
memzero(ret, num * sizeof(pgd_t));

@@ -76,61 +71,43 @@ static inline pgd_t *pgd_alloc(struct mm_struct *mm)

static inline void pgd_free(struct mm_struct *mm, pgd_t *pgd)
{
- free_pages((unsigned long)pgd, __get_order_pgd());
-}
-
-
-/*
- * With software-only page-tables, addr-split for traversal is tweakable and
- * that directly governs how big tables would be at each level.
- * Further, the MMU page size is configurable.
- * Thus we need to programatically assert the size constraint
- * All of this is const math, allowing gcc to do constant folding/propagation.
- */
-
-static inline int __get_order_pte(void)
-{
- return get_order(PTRS_PER_PTE * sizeof(pte_t));
+ free_page((unsigned long)pgd);
}

static inline pte_t *pte_alloc_one_kernel(struct mm_struct *mm)
{
pte_t *pte;

- pte = (pte_t *) __get_free_pages(GFP_KERNEL | __GFP_ZERO,
- __get_order_pte());
+ pte = (pte_t *) __get_free_page(GFP_KERNEL | __GFP_ZERO);

return pte;
}

-static inline pgtable_t
-pte_alloc_one(struct mm_struct *mm)
+static inline pgtable_t pte_alloc_one(struct mm_struct *mm)
{
- pgtable_t pte_pg;
struct page *page;

- pte_pg = (pgtable_t)__get_free_pages(GFP_KERNEL, __get_order_pte());
- if (!pte_pg)
- return 0;
- memzero((void *)pte_pg, PTRS_PER_PTE * sizeof(pte_t));
- page = virt_to_page(pte_pg);
+ page = (pgtable_t)alloc_page(GFP_KERNEL | __GFP_ZERO | __GFP_ACCOUNT);
+ if (!page)
+ return NULL;
+
if (!pgtable_pte_page_ctor(page)) {
__free_page(page);
- return 0;
+ return NULL;
}

- return pte_pg;
+ return page;
}

static inline void pte_free_kernel(struct mm_struct *mm, pte_t *pte)
{
- free_pages((unsigned long)pte, __get_order_pte()); /* takes phy addr */
+ free_page((unsigned long)pte);
}

-static inline void pte_free(struct mm_struct *mm, pgtable_t ptep)
+static inline void pte_free(struct mm_struct *mm, pgtable_t pte_page)
{
- pgtable_pte_page_dtor(virt_to_page(ptep));
- free_pages((unsigned long)ptep, __get_order_pte());
+ pgtable_pte_page_dtor(pte_page);
+ __free_page(pte_page);
}

#define __pte_free_tlb(tlb, pte, addr) pte_free((tlb)->mm, pte)
diff --git a/arch/arc/mm/init.c b/arch/arc/mm/init.c
index c083bf660cec..46ad9aee7a73 100644
--- a/arch/arc/mm/init.c
+++ b/arch/arc/mm/init.c
@@ -189,6 +189,9 @@ void __init mem_init(void)
{
memblock_free_all();
highmem_init();
+
+ BUILD_BUG_ON((PTRS_PER_PGD * sizeof(pgd_t)) > PAGE_SIZE);
+ BUILD_BUG_ON((PTRS_PER_PTE * sizeof(pte_t)) > PAGE_SIZE);
}

#ifdef CONFIG_HIGHMEM
--
2.25.1