Merge branch 'akpm' (patches from Andrew)

Merge misc fixes from Andrew Morton:
 "12 fixes"

* emailed patches from Andrew Morton <akpm@linux-foundation.org>:
  dmapool: fix overflow condition in pool_find_page()
  thermal: avoid division by zero in power allocator
  memcg: remove pcp_counter_lock
  kprobes: use _do_fork() in samples to make them work again
  drivers/input/joystick/Kconfig: zhenhua.c needs BITREVERSE
  memcg: make mem_cgroup_read_stat() unsigned
  memcg: fix dirty page migration
  dax: fix NULL pointer in __dax_pmd_fault()
  mm: hugetlbfs: skip shared VMAs when unmapping private pages to satisfy a fault
  mm/slab: fix unexpected index mapping result of kmalloc_size(INDEX_NODE+1)
  userfaultfd: remove kernel header include from uapi header
  arch/x86/include/asm/efi.h: fix build failure

include/linux/memcontrol.h

@@ -242,7 +242,6 @@ struct mem_cgroup {
 	 * percpu counter.
 	 */
 	struct mem_cgroup_stat_cpu __percpu *stat;
-	spinlock_t pcp_counter_lock;
 
 #if defined(CONFIG_MEMCG_KMEM) && defined(CONFIG_INET)
 	struct cg_proto tcp_mem;

include/linux/mm.h

@@ -905,6 +905,27 @@ static inline void set_page_links(struct page *page, enum zone_type zone,
 #endif
 }
 
+#ifdef CONFIG_MEMCG
+static inline struct mem_cgroup *page_memcg(struct page *page)
+{
+	return page->mem_cgroup;
+}
+
+static inline void set_page_memcg(struct page *page, struct mem_cgroup *memcg)
+{
+	page->mem_cgroup = memcg;
+}
+#else
+static inline struct mem_cgroup *page_memcg(struct page *page)
+{
+	return NULL;
+}
+
+static inline void set_page_memcg(struct page *page, struct mem_cgroup *memcg)
+{
+}
+#endif
+
 /*
  * Some inline functions in vmstat.h depend on page_zone()
  */