hashtable: add hash_for_each_possible_rcu_notrace()

This adds hash_for_each_possible_rcu_notrace() which is basically
a notrace clone of hash_for_each_possible_rcu() which cannot be
used in real mode due to its tracing/debugging capability.

Signed-off-by: Alexey Kardashevskiy <aik@ozlabs.ru>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
diff --git a/include/linux/hashtable.h b/include/linux/hashtable.h
index a9df51f..519b6e2 100644
--- a/include/linux/hashtable.h
+++ b/include/linux/hashtable.h
@@ -174,6 +174,21 @@
 		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