[PATCH v2 2/6] parisc: mm: Ensure pagetable_pmd_[cd]tor are called

[Kevin Brodsky <kevin.brodsky@arm.com>]

The implementation of pmd_{alloc_one,free} on parisc requires a
non-zero allocation order, but is completely standard aside from
that. Let's reuse the generic implementation of pmd_alloc_one().
Explicit zeroing is not needed as GFP_PGTABLE_KERNEL includes
__GFP_ZERO. The generic pmd_free() can handle higher allocation
orders so we don't need to define our own.

These changes ensure that pagetable_pmd_[cd]tor are called,
improving the accounting of page table pages.

Acked-by: Dave Hansen <dave.hansen@linux.intel.com>
Signed-off-by: Kevin Brodsky <kevin.brodsky@arm.com>
---
 arch/parisc/include/asm/pgalloc.h | 23 ++++++++++++-----------
 1 file changed, 12 insertions(+), 11 deletions(-)

diff --git a/arch/parisc/include/asm/pgalloc.h b/arch/parisc/include/asm/pgalloc.h
index e3e142b1c5c5..3e8dbd79670b 100644
--- a/arch/parisc/include/asm/pgalloc.h
+++ b/arch/parisc/include/asm/pgalloc.h
@@ -11,7 +11,6 @@
 #include <asm/cache.h>
 
 #define __HAVE_ARCH_PMD_ALLOC_ONE
-#define __HAVE_ARCH_PMD_FREE
 #define __HAVE_ARCH_PGD_FREE
 #include <asm-generic/pgalloc.h>
 
@@ -46,17 +45,19 @@ static inline void pud_populate(struct mm_struct *mm, pud_t *pud, pmd_t *pmd)
 
 static inline pmd_t *pmd_alloc_one(struct mm_struct *mm, unsigned long address)
 {
-	pmd_t *pmd;
+	struct ptdesc *ptdesc;
+	gfp_t gfp = GFP_PGTABLE_USER;
 
-	pmd = (pmd_t *)__get_free_pages(GFP_PGTABLE_KERNEL, PMD_TABLE_ORDER);
-	if (likely(pmd))
-		memset ((void *)pmd, 0, PAGE_SIZE << PMD_TABLE_ORDER);
-	return pmd;
-}
-
-static inline void pmd_free(struct mm_struct *mm, pmd_t *pmd)
-{
-	free_pages((unsigned long)pmd, PMD_TABLE_ORDER);
+	if (mm == &init_mm)
+		gfp = GFP_PGTABLE_KERNEL;
+	ptdesc = pagetable_alloc(gfp, PMD_TABLE_ORDER);
+	if (!ptdesc)
+		return NULL;
+	if (!pagetable_pmd_ctor(ptdesc)) {
+		pagetable_free(ptdesc);
+		return NULL;
+	}
+	return ptdesc_address(ptdesc);
 }
 #endif
 
-- 
2.47.0