4 files changed, 34 insertions, 1 deletions
diff --git a/include/linux/hashtable.h b/include/linux/hashtable.h
index a9df51f5d54c..519b6e2d769e 100644
--- a/include/linux/hashtable.h
+++ b/include/linux/hashtable.h
@@ -174,6 +174,21 @@ static inline void hash_del_rcu(struct hlist_node *node)
 		member)
 
 /**
+ * hash_for_each_possible_rcu_notrace - iterate over all possible objects hashing
+ * to the same bucket in an rcu enabled hashtable in a rcu enabled hashtable
+ * @name: hashtable to iterate
+ * @obj: the type * to use as a loop cursor for each entry
+ * @member: the name of the hlist_node within the struct
+ * @key: the key of the objects to iterate over
+ *
+ * This is the same as hash_for_each_possible_rcu() except that it does
+ * not do any RCU debugging or tracing.
+ */
+#define hash_for_each_possible_rcu_notrace(name, obj, member, key) \
+	hlist_for_each_entry_rcu_notrace(obj, \
+		&name[hash_min(key, HASH_BITS(name))], member)
+
+/**
  * hash_for_each_possible_safe - iterate over all possible objects hashing to the
  * same bucket safe against removals
  * @name: hashtable to iterate
diff --git a/include/linux/mm.h b/include/linux/mm.h
index 81443d557a2e..8aa4006b9636 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -297,12 +297,26 @@ static inline int put_page_testzero(struct page *page)
 /*
  * Try to grab a ref unless the page has a refcount of zero, return false if
  * that is the case.
+ * This can be called when MMU is off so it must not access
+ * any of the virtual mappings.
  */
 static inline int get_page_unless_zero(struct page *page)
 {
 	return atomic_inc_not_zero(&page->_count);
 }
 
+/*
+ * Try to drop a ref unless the page has a refcount of one, return false if
+ * that is the case.
+ * This is to make sure that the refcount won't become zero after this drop.
+ * This can be called when MMU is off so it must not access
+ * any of the virtual mappings.
+ */
+static inline int put_page_unless_one(struct page *page)
+{
+	return atomic_add_unless(&page->_count, -1, 1);
+}
+
 extern int page_is_ram(unsigned long pfn);
 
 /* Support for virtually mapped pages */
diff --git a/include/linux/of.h b/include/linux/of.h
index f95aee391e30..c08c07e249b3 100644
--- a/include/linux/of.h
+++ b/include/linux/of.h
@@ -226,6 +226,8 @@ static inline int of_get_child_count(const struct device_node *np)
 	return num;
 }
 
+/* cache lookup */
+extern struct device_node *of_find_next_cache_node(const struct device_node *);
 extern struct device_node *of_find_node_with_property(
 	struct device_node *from, const char *prop_name);
 #define for_each_node_with_property(dn, prop_name) \
diff --git a/include/linux/page-flags.h b/include/linux/page-flags.h
index 6d53675c2b54..98ada58f9942 100644
--- a/include/linux/page-flags.h
+++ b/include/linux/page-flags.h
@@ -329,7 +329,9 @@ static inline void set_page_writeback(struct page *page)
  * System with lots of page flags available. This allows separate
  * flags for PageHead() and PageTail() checks of compound pages so that bit
  * tests can be used in performance sensitive paths. PageCompound is
- * generally not used in hot code paths.
+ * generally not used in hot code paths except arch/powerpc/mm/init_64.c
+ * and arch/powerpc/kvm/book3s_64_vio_hv.c which use it to detect huge pages
+ * and avoid handling those in real mode.
  */
 __PAGEFLAG(Head, head) CLEARPAGEFLAG(Head, head)
 __PAGEFLAG(Tail, tail)