radix-tree: ensure counts are initialised
radix_tree_join() was freeing nodes with a non-zero ->exceptional count,
and radix_tree_split() wasn't zeroing ->exceptional when it allocated
the new node. Fix this by making all callers of radix_tree_node_alloc()
pass in the new counts (and some other always-initialised fields), which
will prevent the problem recurring if in future we decide to do
something similar.
Link: http://lkml.kernel.org/r/1481667692-14500-3-git-send-email-mawilcox@linuxonhyperv.com
Signed-off-by: Matthew Wilcox <mawilcox@microsoft.com>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Konstantin Khlebnikov <koct9i@gmail.com>
Cc: Ross Zwisler <ross.zwisler@linux.intel.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 d09c17d..0019aca 100644
--- a/lib/radix-tree.c
+++ b/lib/radix-tree.c
@@ -288,7 +288,10 @@
* that the caller has pinned this thread of control to the current CPU.
*/
static struct radix_tree_node *
-radix_tree_node_alloc(struct radix_tree_root *root)
+radix_tree_node_alloc(struct radix_tree_root *root,
+ struct radix_tree_node *parent,
+ unsigned int shift, unsigned int offset,
+ unsigned int count, unsigned int exceptional)
{
struct radix_tree_node *ret = NULL;
gfp_t gfp_mask = root_gfp_mask(root);
@@ -333,6 +336,13 @@
ret = kmem_cache_alloc(radix_tree_node_cachep, gfp_mask);
out:
BUG_ON(radix_tree_is_internal_node(ret));
+ if (ret) {
+ ret->parent = parent;
+ ret->shift = shift;
+ ret->offset = offset;
+ ret->count = count;
+ ret->exceptional = exceptional;
+ }
return ret;
}
@@ -538,8 +548,8 @@
goto out;
do {
- struct radix_tree_node *node = radix_tree_node_alloc(root);
-
+ struct radix_tree_node *node = radix_tree_node_alloc(root,
+ NULL, shift, 0, 1, 0);
if (!node)
return -ENOMEM;
@@ -550,16 +560,11 @@
}
BUG_ON(shift > BITS_PER_LONG);
- node->shift = shift;
- node->offset = 0;
- node->count = 1;
- node->parent = NULL;
if (radix_tree_is_internal_node(slot)) {
entry_to_node(slot)->parent = node;
- } else {
+ } else if (radix_tree_exceptional_entry(slot)) {
/* Moving an exceptional root->rnode to a node */
- if (radix_tree_exceptional_entry(slot))
- node->exceptional = 1;
+ node->exceptional = 1;
}
node->slots[0] = slot;
slot = node_to_entry(node);
@@ -712,14 +717,10 @@
shift -= RADIX_TREE_MAP_SHIFT;
if (child == NULL) {
/* Have to add a child node. */
- child = radix_tree_node_alloc(root);
+ child = radix_tree_node_alloc(root, node, shift,
+ offset, 0, 0);
if (!child)
return -ENOMEM;
- child->shift = shift;
- child->offset = offset;
- child->count = 0;
- child->exceptional = 0;
- child->parent = node;
rcu_assign_pointer(*slot, node_to_entry(child));
if (node)
node->count++;
@@ -1209,13 +1210,11 @@
for (;;) {
if (node->shift > order) {
- child = radix_tree_node_alloc(root);
+ child = radix_tree_node_alloc(root, node,
+ node->shift - RADIX_TREE_MAP_SHIFT,
+ offset, 0, 0);
if (!child)
goto nomem;
- child->shift = node->shift - RADIX_TREE_MAP_SHIFT;
- child->offset = offset;
- child->count = 0;
- child->parent = node;
if (node != parent) {
node->count++;
node->slots[offset] = node_to_entry(child);