[PATCHv3 06/41] radix-tree: Handle multiorder entries being deleted by replace_clear_tags

Kirill A. Shutemov
2016-09-15T11:54:48Z

From: Matthew Wilcox <willy@infradead.org>

radix_tree_replace_clear_tags() can be called with NULL as the replacement
value; in this case we need to delete sibling entries which point to
the slot.

Signed-off-by: Matthew Wilcox <willy@infradead.org>
Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
---
lib/radix-tree.c | 11 ++++++++++-
1 file changed, 10 insertions(+), 1 deletion(-)

diff --git a/lib/radix-tree.c b/lib/radix-tree.c
index e58855435c01..57c15c4d0796 100644
--- a/lib/radix-tree.c
+++ b/lib/radix-tree.c
@@ -1805,17 +1805,23 @@ void *radix_tree_delete(struct radix_tree_root *root, unsigned long index)
}
EXPORT_SYMBOL(radix_tree_delete);

+/*
+ * If the caller passes NULL for @entry, it must take care to adjust
+ * node->count. See page_cache_tree_delete() for an example.
+ */
struct radix_tree_node *radix_tree_replace_clear_tags(
struct radix_tree_root *root,
unsigned long index, void *entry)
{
struct radix_tree_node *node;
void **slot;
+ unsigned int offset;

__radix_tree_lookup(root, index, &node, &slot);

if (node) {
- unsigned int tag, offset = get_slot_offset(node, slot);
+ unsigned int tag;
+ offset = get_slot_offset(node, slot);
for (tag = 0; tag < RADIX_TREE_MAX_TAGS; tag++)
node_tag_clear(root, node, tag, offset);
} else {
@@ -1824,6 +1830,9 @@ struct radix_tree_node *radix_tree_replace_clear_tags(
}

radix_tree_replace_slot(slot, entry);
+ if (!entry && node)
+ delete_sibling_entries(node, node_to_entry(slot), offset);
+
return node;
}