parisc: mm: ensure pagetable_pmd_[cd]tor are called

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.

Link: https://lkml.kernel.org/r/[email protected]
Signed-off-by: Kevin Brodsky <[email protected]>
Acked-by: Dave Hansen <[email protected]>
Acked-by: Qi Zheng <[email protected]>
Cc: Andy Lutomirski <[email protected]>
Cc: Catalin Marinas <[email protected]>
Cc: Ingo Molnar <[email protected]>
Cc: Linus Walleij <[email protected]>
Cc: Matthew Wilcox (Oracle) <[email protected]>
Cc: Mike Rapoport (Microsoft) <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Cc: Ryan Roberts <[email protected]>
Cc: Thomas Gleixner <[email protected]>
Cc: Will Deacon <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>

Author: kevin-brodsky-arm

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