pgalloc: convert various functions to use ptdescs

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.

Link: https://lkml.kernel.org/r/[e-mail]
Signed-off-by: Vishal Moola (Oracle) <[e-mail]>
Cc: Arnd Bergmann <[e-mail]>
Cc: Catalin Marinas <[e-mail]>
Cc: Christophe Leroy <[e-mail]>
Cc: Claudio Imbrenda <[e-mail]>
Cc: Dave Hansen <[e-mail]>
Cc: David Hildenbrand <[e-mail]>
Cc: "David S. Miller" <[e-mail]>
Cc: Dinh Nguyen <[e-mail]>
Cc: Geert Uytterhoeven <[e-mail]>
Cc: Geert Uytterhoeven <[e-mail]>
Cc: Guo Ren <[e-mail]>
Cc: Huacai Chen <[e-mail]>
Cc: Hugh Dickins <[e-mail]>
Cc: John Paul Adrian Glaubitz <[e-mail]>
Cc: Jonas Bonn <[e-mail]>
Cc: Matthew Wilcox <[e-mail]>
Cc: Mike Rapoport (IBM) <[e-mail]>
Cc: Palmer Dabbelt <[e-mail]>
Cc: Paul Walmsley <[e-mail]>
Cc: Richard Weinberger <[e-mail]>
Cc: Thomas Bogendoerfer <[e-mail]>
Cc: Yoshinori Sato <[e-mail]>
Signed-off-by: Andrew Morton <[e-mail]>

include/asm-generic/pgalloc.h

···
 #define GFP_PGTABLE_USER	(GFP_PGTABLE_KERNEL | __GFP_ACCOUNT)
 
 /**
- * __pte_alloc_one_kernel - allocate a page for PTE-level kernel page table
+ * __pte_alloc_one_kernel - allocate memory for a PTE-level kernel page table
  * @mm: the mm_struct of the current context
  *
  * This function is intended for architectures that need
···
  */
 static inline pte_t *__pte_alloc_one_kernel(struct mm_struct *mm)
 {
-	return (pte_t *)__get_free_page(GFP_PGTABLE_KERNEL);
+	struct ptdesc *ptdesc = pagetable_alloc(GFP_PGTABLE_KERNEL &
+			~__GFP_HIGHMEM, 0);
+
+	if (!ptdesc)
+		return NULL;
+	return ptdesc_address(ptdesc);
 }
 
 #ifndef __HAVE_ARCH_PTE_ALLOC_ONE_KERNEL
 /**
- * pte_alloc_one_kernel - allocate a page for PTE-level kernel page table
+ * pte_alloc_one_kernel - allocate memory for a PTE-level kernel page table
  * @mm: the mm_struct of the current context
  *
  * Return: pointer to the allocated memory or %NULL on error
···
 #endif
 
 /**
- * pte_free_kernel - free PTE-level kernel page table page
+ * pte_free_kernel - free PTE-level kernel page table memory
  * @mm: the mm_struct of the current context
  * @pte: pointer to the memory containing the page table
  */
 static inline void pte_free_kernel(struct mm_struct *mm, pte_t *pte)
 {
-	free_page((unsigned long)pte);
+	pagetable_free(virt_to_ptdesc(pte));
 }
 
 /**
- * __pte_alloc_one - allocate a page for PTE-level user page table
+ * __pte_alloc_one - allocate memory for a PTE-level user page table
  * @mm: the mm_struct of the current context
  * @gfp: GFP flags to use for the allocation
  *
- * Allocates a page and runs the pgtable_pte_page_ctor().
+ * Allocate memory for a page table and ptdesc and runs pagetable_pte_ctor().
  *
  * This function is intended for architectures that need
  * anything beyond simple page allocation or must have custom GFP flags.
  *
- * Return: `struct page` initialized as page table or %NULL on error
+ * Return: `struct page` referencing the ptdesc or %NULL on error
  */
 static inline pgtable_t __pte_alloc_one(struct mm_struct *mm, gfp_t gfp)
 {
-	struct page *pte;
+	struct ptdesc *ptdesc;
 
-	pte = alloc_page(gfp);
-	if (!pte)
+	ptdesc = pagetable_alloc(gfp, 0);
+	if (!ptdesc)
 		return NULL;
-	if (!pgtable_pte_page_ctor(pte)) {
-		__free_page(pte);
+	if (!pagetable_pte_ctor(ptdesc)) {
+		pagetable_free(ptdesc);
 		return NULL;
 	}
 
-	return pte;
+	return ptdesc_page(ptdesc);
 }
 
 #ifndef __HAVE_ARCH_PTE_ALLOC_ONE
···
  * pte_alloc_one - allocate a page for PTE-level user page table
  * @mm: the mm_struct of the current context
  *
- * Allocates a page and runs the pgtable_pte_page_ctor().
+ * Allocate memory for a page table and ptdesc and runs pagetable_pte_ctor().
  *
- * Return: `struct page` initialized as page table or %NULL on error
+ * Return: `struct page` referencing the ptdesc or %NULL on error
  */
 static inline pgtable_t pte_alloc_one(struct mm_struct *mm)
 {
···
  */
 
 /**
- * pte_free - free PTE-level user page table page
+ * pte_free - free PTE-level user page table memory
  * @mm: the mm_struct of the current context
- * @pte_page: the `struct page` representing the page table
+ * @pte_page: the `struct page` referencing the ptdesc
  */
 static inline void pte_free(struct mm_struct *mm, struct page *pte_page)
 {
-	pgtable_pte_page_dtor(pte_page);
-	__free_page(pte_page);
+	struct ptdesc *ptdesc = page_ptdesc(pte_page);
+
+	pagetable_pte_dtor(ptdesc);
+	pagetable_free(ptdesc);
 }
 
 
···
 
 #ifndef __HAVE_ARCH_PMD_ALLOC_ONE
 /**
- * pmd_alloc_one - allocate a page for PMD-level page table
+ * pmd_alloc_one - allocate memory for a PMD-level page table
  * @mm: the mm_struct of the current context
  *
- * Allocates a page and runs the pgtable_pmd_page_ctor().
+ * Allocate memory for a page table and ptdesc and runs pagetable_pmd_ctor().
+ *
  * Allocations use %GFP_PGTABLE_USER in user context and
  * %GFP_PGTABLE_KERNEL in kernel context.
  *
···
  */
 static inline pmd_t *pmd_alloc_one(struct mm_struct *mm, unsigned long addr)
 {
-	struct page *page;
+	struct ptdesc *ptdesc;
 	gfp_t gfp = GFP_PGTABLE_USER;
 
 	if (mm == &init_mm)
 		gfp = GFP_PGTABLE_KERNEL;
-	page = alloc_page(gfp);
-	if (!page)
+	ptdesc = pagetable_alloc(gfp, 0);
+	if (!ptdesc)
 		return NULL;
-	if (!pgtable_pmd_page_ctor(page)) {
-		__free_page(page);
+	if (!pagetable_pmd_ctor(ptdesc)) {
+		pagetable_free(ptdesc);
 		return NULL;
 	}
-	return (pmd_t *)page_address(page);
+	return ptdesc_address(ptdesc);
 }
 #endif
 
 #ifndef __HAVE_ARCH_PMD_FREE
 static inline void pmd_free(struct mm_struct *mm, pmd_t *pmd)
 {
+	struct ptdesc *ptdesc = virt_to_ptdesc(pmd);
+
 	BUG_ON((unsigned long)pmd & (PAGE_SIZE-1));
-	pgtable_pmd_page_dtor(virt_to_page(pmd));
-	free_page((unsigned long)pmd);
+	pagetable_pmd_dtor(ptdesc);
+	pagetable_free(ptdesc);
 }
 #endif
 
···
 static inline pud_t *__pud_alloc_one(struct mm_struct *mm, unsigned long addr)
 {
 	gfp_t gfp = GFP_PGTABLE_USER;
+	struct ptdesc *ptdesc;
 
 	if (mm == &init_mm)
 		gfp = GFP_PGTABLE_KERNEL;
-	return (pud_t *)get_zeroed_page(gfp);
+	gfp &= ~__GFP_HIGHMEM;
+
+	ptdesc = pagetable_alloc(gfp, 0);
+	if (!ptdesc)
+		return NULL;
+	return ptdesc_address(ptdesc);
 }
 
 #ifndef __HAVE_ARCH_PUD_ALLOC_ONE
 /**
- * pud_alloc_one - allocate a page for PUD-level page table
+ * pud_alloc_one - allocate memory for a PUD-level page table
  * @mm: the mm_struct of the current context
  *
- * Allocates a page using %GFP_PGTABLE_USER for user context and
- * %GFP_PGTABLE_KERNEL for kernel context.
+ * Allocate memory for a page table using %GFP_PGTABLE_USER for user context
+ * and %GFP_PGTABLE_KERNEL for kernel context.
  *
  * Return: pointer to the allocated memory or %NULL on error
  */
···
 static inline void __pud_free(struct mm_struct *mm, pud_t *pud)
 {
 	BUG_ON((unsigned long)pud & (PAGE_SIZE-1));
-	free_page((unsigned long)pud);
+	pagetable_free(virt_to_ptdesc(pud));
 }
 
 #ifndef __HAVE_ARCH_PUD_FREE
···
 #ifndef __HAVE_ARCH_PGD_FREE
 static inline void pgd_free(struct mm_struct *mm, pgd_t *pgd)
 {
-	free_page((unsigned long)pgd);
+	pagetable_free(virt_to_ptdesc(pgd));
 }
 #endif