arm: switch to generic version of pte allocation

Replace __get_free_page() and alloc_pages() calls with the generic
__pte_alloc_one_kernel() and __pte_alloc_one().

There is no functional change for the kernel PTE allocation.

The difference for the user PTEs, is that the clear_pte_table() is now
called after pgtable_page_ctor() and the addition of __GFP_ACCOUNT to the
GFP flags.

The conversion to the generic version of pte_free_kernel() removes the NULL
check for pte.

The pte_free() version on arm is identical to the generic one and can be
simply dropped.

Link: http://lkml.kernel.org/r/1557296232-15361-4-git-send-email-rppt@linux.ibm.com
Signed-off-by: Mike Rapoport <rppt@linux.ibm.com>
Cc: Albert Ou <aou@eecs.berkeley.edu>
Cc: Anshuman Khandual <anshuman.khandual@arm.com>
Cc: Anton Ivanov <anton.ivanov@cambridgegreys.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Greentime Hu <green.hu@gmail.com>
Cc: Guan Xuetao <gxt@pku.edu.cn>
Cc: Guo Ren <guoren@kernel.org>
Cc: Guo Ren <ren_guo@c-sky.com>
Cc: Helge Deller <deller@gmx.de>
Cc: Ley Foon Tan <lftan@altera.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Matt Turner <mattst88@gmail.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Palmer Dabbelt <palmer@sifive.com>
Cc: Paul Burton <paul.burton@mips.com>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: Richard Kuo <rkuo@codeaurora.org>
Cc: Richard Weinberger <richard@nod.at>
Cc: Russell King <linux@armlinux.org.uk>
Cc: Sam Creasey <sammy@sammy.net>
Cc: Vincent Chen <deanbo422@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

arch/arm/include/asm/pgalloc.h

@@ -54,8 +54,6 @@ static inline void pud_populate(struct mm_struct *mm, pud_t *pud, pmd_t *pmd)
 extern pgd_t *pgd_alloc(struct mm_struct *mm);
 extern void pgd_free(struct mm_struct *mm, pgd_t *pgd);
 
-#define PGALLOC_GFP	(GFP_KERNEL | __GFP_ZERO)
-
 static inline void clean_pte_table(pte_t *pte)
 {
 	clean_dcache_area(pte + PTE_HWTABLE_PTRS, PTE_HWTABLE_SIZE);
@@ -77,54 +75,41 @@ static inline void clean_pte_table(pte_t *pte)
  *  |  h/w pt 1  |
  *  +------------+
  */
+
+#define __HAVE_ARCH_PTE_ALLOC_ONE_KERNEL
+#define __HAVE_ARCH_PTE_ALLOC_ONE
+#include <asm-generic/pgalloc.h>
+
 static inline pte_t *
 pte_alloc_one_kernel(struct mm_struct *mm)
 {
-	pte_t *pte;
+	pte_t *pte = __pte_alloc_one_kernel(mm);
 
-	pte = (pte_t *)__get_free_page(PGALLOC_GFP);
 	if (pte)
 		clean_pte_table(pte);
 
 	return pte;
 }
 
+#ifdef CONFIG_HIGHPTE
+#define PGTABLE_HIGHMEM __GFP_HIGHMEM
+#else
+#define PGTABLE_HIGHMEM 0
+#endif
+
 static inline pgtable_t
 pte_alloc_one(struct mm_struct *mm)
 {
 	struct page *pte;
 
-#ifdef CONFIG_HIGHPTE
+	pte = __pte_alloc_one(mm, GFP_PGTABLE_USER | PGTABLE_HIGHMEM);
-	pte = alloc_pages(PGALLOC_GFP | __GFP_HIGHMEM, 0);
-#else
-	pte = alloc_pages(PGALLOC_GFP, 0);
-#endif
 	if (!pte)
 		return NULL;
 	if (!PageHighMem(pte))
 		clean_pte_table(page_address(pte));
-	if (!pgtable_page_ctor(pte)) {
-		__free_page(pte);
-		return NULL;
-	}
 	return pte;
 }
 
-/*
- * Free one PTE table.
- */
-static inline void pte_free_kernel(struct mm_struct *mm, pte_t *pte)
-{
-	if (pte)
-		free_page((unsigned long)pte);
-}
-
-static inline void pte_free(struct mm_struct *mm, pgtable_t pte)
-{
-	pgtable_page_dtor(pte);
-	__free_page(pte);
-}
-
 static inline void __pmd_populate(pmd_t *pmdp, phys_addr_t pte,
 				  pmdval_t prot)
 {

arch/arm/mm/mmu.c

@@ -729,7 +729,7 @@ static void __init *early_alloc(unsigned long sz)
 
 static void *__init late_alloc(unsigned long sz)
 {
-	void *ptr = (void *)__get_free_pages(PGALLOC_GFP, get_order(sz));
+	void *ptr = (void *)__get_free_pages(GFP_PGTABLE_KERNEL, get_order(sz));
 
 	if (!ptr || !pgtable_page_ctor(virt_to_page(ptr)))
 		BUG();