radix-tree: fix replacement for multiorder entries
When replacing an entry with NULL, we need to delete any sibling
entries. Also account deleting exceptional entries properly. Also fix
a bug with radix_tree_iter_replace() where we would fail to remove
entirely freed nodes. Also fix accounting bug when switching between
normal and exceptional entries with replace_slot. Also add testcases
for all these bugs.
Link: http://lkml.kernel.org/r/1480369871-5271-61-git-send-email-mawilcox@linuxonhyperv.com
Signed-off-by: Matthew Wilcox <mawilcox@microsoft.com>
Tested-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Konstantin Khlebnikov <koct9i@gmail.com>
Cc: Ross Zwisler <ross.zwisler@linux.intel.com>
Cc: Matthew Wilcox <mawilcox@microsoft.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/lib/radix-tree.c b/lib/radix-tree.c
index be1183e..d09c17d 100644
--- a/lib/radix-tree.c
+++ b/lib/radix-tree.c
@@ -977,6 +977,24 @@ void *radix_tree_lookup(struct radix_tree_root *root, unsigned long index)
}
EXPORT_SYMBOL(radix_tree_lookup);
+static inline int slot_count(struct radix_tree_node *node,
+ void **slot)
+{
+ int n = 1;
+#ifdef CONFIG_RADIX_TREE_MULTIORDER
+ void *ptr = node_to_entry(slot);
+ unsigned offset = get_slot_offset(node, slot);
+ int i;
+
+ for (i = 1; offset + i < RADIX_TREE_MAP_SIZE; i++) {
+ if (node->slots[offset + i] != ptr)
+ break;
+ n++;
+ }
+#endif
+ return n;
+}
+
static void replace_slot(struct radix_tree_root *root,
struct radix_tree_node *node,
void **slot, void *item,
@@ -995,12 +1013,35 @@ static void replace_slot(struct radix_tree_root *root,
if (node) {
node->count += count;
- node->exceptional += exceptional;
+ if (exceptional) {
+ exceptional *= slot_count(node, slot);
+ node->exceptional += exceptional;
+ }
}
rcu_assign_pointer(*slot, item);
}
+static inline void delete_sibling_entries(struct radix_tree_node *node,
+ void **slot)
+{
+#ifdef CONFIG_RADIX_TREE_MULTIORDER
+ bool exceptional = radix_tree_exceptional_entry(*slot);
+ void *ptr = node_to_entry(slot);
+ unsigned offset = get_slot_offset(node, slot);
+ int i;
+
+ for (i = 1; offset + i < RADIX_TREE_MAP_SIZE; i++) {
+ if (node->slots[offset + i] != ptr)
+ break;
+ node->slots[offset + i] = NULL;
+ node->count--;
+ if (exceptional)
+ node->exceptional--;
+ }
+#endif
+}
+
/**
* __radix_tree_replace - replace item in a slot
* @root: radix tree root
@@ -1018,6 +1059,8 @@ void __radix_tree_replace(struct radix_tree_root *root,
void **slot, void *item,
radix_tree_update_node_t update_node, void *private)
{
+ if (!item)
+ delete_sibling_entries(node, slot);
/*
* This function supports replacing exceptional entries and
* deleting entries, but that needs accounting against the
@@ -1794,20 +1837,6 @@ void __radix_tree_delete_node(struct radix_tree_root *root,
delete_node(root, node, NULL, NULL);
}
-static inline void delete_sibling_entries(struct radix_tree_node *node,
- void *ptr, unsigned offset)
-{
-#ifdef CONFIG_RADIX_TREE_MULTIORDER
- int i;
- for (i = 1; offset + i < RADIX_TREE_MAP_SIZE; i++) {
- if (node->slots[offset + i] != ptr)
- break;
- node->slots[offset + i] = NULL;
- node->count--;
- }
-#endif
-}
-
/**
* radix_tree_delete_item - delete an item from a radix tree
* @root: radix tree root
@@ -1847,7 +1876,6 @@ void *radix_tree_delete_item(struct radix_tree_root *root,
for (tag = 0; tag < RADIX_TREE_MAX_TAGS; tag++)
node_tag_clear(root, node, tag, offset);
- delete_sibling_entries(node, node_to_entry(slot), offset);
__radix_tree_replace(root, node, slot, NULL, NULL, NULL);
return entry;