X-Git-Url: https://git.karo-electronics.de/?a=blobdiff_plain;f=include%2Flinux%2Fradix-tree.h;h=23241c2feccee7b542ac1e984c91b13a02be0541;hb=2aa15890f3c191326678f1bd68af61ec6b8753ec;hp=ab2baa5c488453cba50bf564d6220038d0224867;hpb=e3166331a3288dd7184548896a1c7ab682f0dbe8;p=karo-tx-linux.git

diff --git a/include/linux/radix-tree.h b/include/linux/radix-tree.h
index ab2baa5c4884..23241c2fecce 100644
--- a/include/linux/radix-tree.h
+++ b/include/linux/radix-tree.h
@@ -145,6 +145,22 @@ static inline void *radix_tree_deref_slot(void **pslot)
 	return rcu_dereference(*pslot);
 }
 
+/**
+ * radix_tree_deref_slot_protected	- dereference a slot without RCU lock but with tree lock held
+ * @pslot:	pointer to slot, returned by radix_tree_lookup_slot
+ * Returns:	item that was stored in that slot with any direct pointer flag
+ *		removed.
+ *
+ * Similar to radix_tree_deref_slot but only used during migration when a pages
+ * mapping is being moved. The caller does not hold the RCU read lock but it
+ * must hold the tree lock to prevent parallel updates.
+ */
+static inline void *radix_tree_deref_slot_protected(void **pslot,
+							spinlock_t *treelock)
+{
+	return rcu_dereference_protected(*pslot, lockdep_is_held(treelock));
+}
+
 /**
  * radix_tree_deref_retry	- check radix_tree_deref_slot
  * @arg:	pointer returned by radix_tree_deref_slot