diff options
Diffstat (limited to 'lib/radix-tree.c')
| -rw-r--r-- | lib/radix-tree.c | 63 |
1 files changed, 49 insertions, 14 deletions
diff --git a/lib/radix-tree.c b/lib/radix-tree.c index 7885796d35ae..f91d5b0af654 100644 --- a/lib/radix-tree.c +++ b/lib/radix-tree.c @@ -753,19 +753,10 @@ void *radix_tree_lookup(struct radix_tree_root *root, unsigned long index) } EXPORT_SYMBOL(radix_tree_lookup); -/** - * __radix_tree_replace - replace item in a slot - * @root: radix tree root - * @node: pointer to tree node - * @slot: pointer to slot in @node - * @item: new item to store in the slot. - * - * For use with __radix_tree_lookup(). Caller must hold tree write locked - * across slot lookup and replacement. - */ -void __radix_tree_replace(struct radix_tree_root *root, - struct radix_tree_node *node, - void **slot, void *item) +static void replace_slot(struct radix_tree_root *root, + struct radix_tree_node *node, + void **slot, void *item, + bool warn_typeswitch) { void *old = rcu_dereference_raw(*slot); int exceptional; @@ -776,7 +767,7 @@ void __radix_tree_replace(struct radix_tree_root *root, exceptional = !!radix_tree_exceptional_entry(item) - !!radix_tree_exceptional_entry(old); - WARN_ON_ONCE(exceptional && !node && slot != (void **)&root->rnode); + WARN_ON_ONCE(warn_typeswitch && exceptional); if (node) node->exceptional += exceptional; @@ -785,6 +776,50 @@ void __radix_tree_replace(struct radix_tree_root *root, } /** + * __radix_tree_replace - replace item in a slot + * @root: radix tree root + * @node: pointer to tree node + * @slot: pointer to slot in @node + * @item: new item to store in the slot. + * + * For use with __radix_tree_lookup(). Caller must hold tree write locked + * across slot lookup and replacement. + */ +void __radix_tree_replace(struct radix_tree_root *root, + struct radix_tree_node *node, + void **slot, void *item) +{ + /* + * This function supports replacing exceptional entries, but + * that needs accounting against the node unless the slot is + * root->rnode. + */ + replace_slot(root, node, slot, item, + !node && slot != (void **)&root->rnode); +} + +/** + * radix_tree_replace_slot - replace item in a slot + * @root: radix tree root + * @slot: pointer to slot + * @item: new item to store in the slot. + * + * For use with radix_tree_lookup_slot(), radix_tree_gang_lookup_slot(), + * radix_tree_gang_lookup_tag_slot(). Caller must hold tree write locked + * across slot lookup and replacement. + * + * NOTE: This cannot be used to switch between non-entries (empty slots), + * regular entries, and exceptional entries, as that requires accounting + * inside the radix tree node. When switching from one type of entry to + * another, use __radix_tree_lookup() and __radix_tree_replace(). + */ +void radix_tree_replace_slot(struct radix_tree_root *root, + void **slot, void *item) +{ + replace_slot(root, NULL, slot, item, true); +} + +/** * radix_tree_tag_set - set a tag on a radix tree node * @root: radix tree root * @index: index key |