radix_tree_lookup_slot() comment

[Peter Zijlstra <a.p.zijlstra@chello.nl>]

Hi Nick,

I noticed the comment above radix_tree_lookup_slot() did not match the
uses in your lockless pagecache. Would this patch be correct?

---
 lib/radix-tree.c |    9 ++++-----
 1 file changed, 4 insertions(+), 5 deletions(-)

Index: linux-2.6-mm/lib/radix-tree.c
===================================================================
--- linux-2.6-mm.orig/lib/radix-tree.c	2006-09-23 20:20:21.000000000 +0200
+++ linux-2.6-mm/lib/radix-tree.c	2006-09-23 20:34:31.000000000 +0200
@@ -380,11 +380,10 @@ EXPORT_SYMBOL(radix_tree_insert);
  *	Returns:  the slot corresponding to the position @index in the
  *	radix tree @root. This is useful for update-if-exists operations.
  *
- *	This function cannot be called under rcu_read_lock, it must be
- *	excluded from writers, as must the returned slot for subsequent
- *	use by radix_tree_deref_slot() and radix_tree_replace slot.
- *	Caller must hold tree write locked across slot lookup and
- *	replace.
+ * 	This function can be called under rcu_read_lock iff the slot is not
+ * 	modified by radix_tree_replace_slot, otherwise it must be called
+ * 	exclusive from other writers. Any dereference of the slot must be done
+ * 	using radix_tree_deref_slot.
  */
 void **radix_tree_lookup_slot(struct radix_tree_root *root, unsigned long index)
 {


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