[PATCH v9 07/20] powerpc/mm: add helpers to get/set mm.context->pte_frag

[Christophe Leroy]

In order to handle pte_fragment functions with single fragment
without adding pte_frag in all mm_context_t, this patch creates
two helpers which do nothing on platforms using a single fragment.

Signed-off-by: Christophe Leroy <christophe.le...@c-s.fr>
---
 arch/powerpc/include/asm/pgtable.h | 25 +++++++++++++++++++++++++
 arch/powerpc/mm/pgtable-frag.c     |  8 ++++----
 2 files changed, 29 insertions(+), 4 deletions(-)

diff --git a/arch/powerpc/include/asm/pgtable.h 
b/arch/powerpc/include/asm/pgtable.h
index 9679b7519a35..314a2890a972 100644
--- a/arch/powerpc/include/asm/pgtable.h
+++ b/arch/powerpc/include/asm/pgtable.h
@@ -110,6 +110,31 @@ void mark_initmem_nx(void);
 static inline void mark_initmem_nx(void) { }
 #endif
 
+/*
+ * When used, PTE_FRAG_NR is defined in subarch pgtable.h
+ * so we are sure it is included when arriving here.
+ */
+#ifdef PTE_FRAG_NR
+static inline void *pte_frag_get(mm_context_t *ctx)
+{
+       return ctx->pte_frag;
+}
+
+static inline void pte_frag_set(mm_context_t *ctx, void *p)
+{
+       ctx->pte_frag = p;
+}
+#else
+static inline void *pte_frag_get(mm_context_t *ctx)
+{
+       return NULL;
+}
+
+static inline void pte_frag_set(mm_context_t *ctx, void *p)
+{
+}
+#endif
+
 #endif /* __ASSEMBLY__ */
 
 #endif /* _ASM_POWERPC_PGTABLE_H */
diff --git a/arch/powerpc/mm/pgtable-frag.c b/arch/powerpc/mm/pgtable-frag.c
index 7544d0d7177d..af23a587f019 100644
--- a/arch/powerpc/mm/pgtable-frag.c
+++ b/arch/powerpc/mm/pgtable-frag.c
@@ -38,7 +38,7 @@ static pte_t *get_pte_from_cache(struct mm_struct *mm)
                return NULL;
 
        spin_lock(&mm->page_table_lock);
-       ret = mm->context.pte_frag;
+       ret = pte_frag_get(&mm->context);
        if (ret) {
                pte_frag = ret + PTE_FRAG_SIZE;
                /*
@@ -46,7 +46,7 @@ static pte_t *get_pte_from_cache(struct mm_struct *mm)
                 */
                if (((unsigned long)pte_frag & ~PAGE_MASK) == 0)
                        pte_frag = NULL;
-               mm->context.pte_frag = pte_frag;
+               pte_frag_set(&mm->context, pte_frag);
        }
        spin_unlock(&mm->page_table_lock);
        return (pte_t *)ret;
@@ -86,9 +86,9 @@ static pte_t *__alloc_for_ptecache(struct mm_struct *mm, int 
kernel)
         * the allocated page with single fragement
         * count.
         */
-       if (likely(!mm->context.pte_frag)) {
+       if (likely(!pte_frag_get(&mm->context))) {
                atomic_set(&page->pt_frag_refcount, PTE_FRAG_NR);
-               mm->context.pte_frag = ret + PTE_FRAG_SIZE;
+               pte_frag_set(&mm->context, ret + PTE_FRAG_SIZE);
        }
        spin_unlock(&mm->page_table_lock);
 
-- 
2.13.3