powerpc/mm: replace hugetlb_cache by PGT_CACHE(PTE_T_ORDER)

Instead of opencoding cache handling for the special case
of hugepage tables having a single pte_t element, this
patch makes use of the common pgtable_cache helpers
Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

arch/powerpc/include/asm/hugetlb.h

@@ -5,8 +5,6 @@
 #ifdef CONFIG_HUGETLB_PAGE
 #include <asm/page.h>
 
-extern struct kmem_cache *hugepte_cache;
-
 #ifdef CONFIG_PPC_BOOK3S_64
 
 #include <asm/book3s/64/hugetlb.h>

arch/powerpc/mm/hugetlbpage.c

@@ -42,6 +42,8 @@ EXPORT_SYMBOL(HPAGE_SHIFT);
 
 #define hugepd_none(hpd)	(hpd_val(hpd) == 0)
 
+#define PTE_T_ORDER	(__builtin_ffs(sizeof(pte_t)) - __builtin_ffs(sizeof(void *)))
+
 pte_t *huge_pte_offset(struct mm_struct *mm, unsigned long addr, unsigned long sz)
 {
 	/*
@@ -61,7 +63,7 @@ static int __hugepte_alloc(struct mm_struct *mm, hugepd_t *hpdp,
 	int num_hugepd;
 
 	if (pshift >= pdshift) {
-		cachep = hugepte_cache;
+		cachep = PGT_CACHE(PTE_T_ORDER);
 		num_hugepd = 1 << (pshift - pdshift);
 	} else {
 		cachep = PGT_CACHE(pdshift - pshift);
@@ -264,7 +266,7 @@ static void hugepd_free_rcu_callback(struct rcu_head *head)
 	unsigned int i;
 
 	for (i = 0; i < batch->index; i++)
-		kmem_cache_free(hugepte_cache, batch->ptes[i]);
+		kmem_cache_free(PGT_CACHE(PTE_T_ORDER), batch->ptes[i]);
 
 	free_page((unsigned long)batch);
 }
@@ -277,7 +279,7 @@ static void hugepd_free(struct mmu_gather *tlb, void *hugepte)
 
 	if (atomic_read(&tlb->mm->mm_users) < 2 ||
 	    mm_is_thread_local(tlb->mm)) {
-		kmem_cache_free(hugepte_cache, hugepte);
+		kmem_cache_free(PGT_CACHE(PTE_T_ORDER), hugepte);
 		put_cpu_var(hugepd_freelist_cur);
 		return;
 	}
@@ -652,7 +654,6 @@ static int __init hugepage_setup_sz(char *str)
 }
 __setup("hugepagesz=", hugepage_setup_sz);
 
-struct kmem_cache *hugepte_cache;
 static int __init hugetlbpage_init(void)
 {
 	int psize;
@@ -702,21 +703,8 @@ static int __init hugetlbpage_init(void)
 		if (pdshift > shift)
 			pgtable_cache_add(pdshift - shift, NULL);
 #if defined(CONFIG_PPC_FSL_BOOK3E) || defined(CONFIG_PPC_8xx)
-		else if (!hugepte_cache) {
-			/*
-			 * Create a kmem cache for hugeptes.  The bottom bits in
-			 * the pte have size information encoded in them, so
-			 * align them to allow this
-			 */
-			hugepte_cache = kmem_cache_create("hugepte-cache",
-							  sizeof(pte_t),
-							  HUGEPD_SHIFT_MASK + 1,
-							  0, NULL);
-			if (hugepte_cache == NULL)
-				panic("%s: Unable to create kmem cache "
-				      "for hugeptes\n", __func__);
-
-		}
+		else
+			pgtable_cache_add(PTE_T_ORDER, NULL);
 #endif
 	}