* Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
*/
+#include <linux/cpu.h>
#include <linux/errno.h>
#include <linux/init.h>
#include <linux/kernel.h>
};
static DEFINE_PER_CPU(struct radix_tree_preload, radix_tree_preloads) = { 0, };
+static inline struct radix_tree_node *entry_to_node(void *ptr)
+{
+ return (void *)((unsigned long)ptr & ~RADIX_TREE_INTERNAL_NODE);
+}
+
static inline void *node_to_entry(void *ptr)
{
return (void *)((unsigned long)ptr | RADIX_TREE_INTERNAL_NODE);
* Returns next bit offset, or size if nothing found.
*/
static __always_inline unsigned long
-radix_tree_find_next_bit(const unsigned long *addr,
- unsigned long size, unsigned long offset)
+radix_tree_find_next_bit(struct radix_tree_node *node, unsigned int tag,
+ unsigned long offset)
{
- if (!__builtin_constant_p(size))
- return find_next_bit(addr, size, offset);
+ const unsigned long *addr = node->tags[tag];
- if (offset < size) {
+ if (offset < RADIX_TREE_MAP_SIZE) {
unsigned long tmp;
addr += offset / BITS_PER_LONG;
if (tmp)
return __ffs(tmp) + offset;
offset = (offset + BITS_PER_LONG) & ~(BITS_PER_LONG - 1);
- while (offset < size) {
+ while (offset < RADIX_TREE_MAP_SIZE) {
tmp = *++addr;
if (tmp)
return __ffs(tmp) + offset;
offset += BITS_PER_LONG;
}
}
- return size;
+ return RADIX_TREE_MAP_SIZE;
+}
+
+static unsigned int iter_offset(const struct radix_tree_iter *iter)
+{
+ return (iter->index >> iter_shift(iter)) & RADIX_TREE_MAP_MASK;
+}
+
+/*
+ * The maximum index which can be stored in a radix tree
+ */
+static inline unsigned long shift_maxindex(unsigned int shift)
+{
+ return (RADIX_TREE_MAP_SIZE << shift) - 1;
+}
+
+static inline unsigned long node_maxindex(struct radix_tree_node *node)
+{
+ return shift_maxindex(node->shift);
}
#ifndef __KERNEL__
{
unsigned long i;
- pr_debug("radix node: %p offset %d tags %lx %lx %lx shift %d count %d parent %p\n",
- node, node->offset,
+ pr_debug("radix node: %p offset %d indices %lu-%lu parent %p tags %lx %lx %lx shift %d count %d exceptional %d\n",
+ node, node->offset, index, index | node_maxindex(node),
+ node->parent,
node->tags[0][0], node->tags[1][0], node->tags[2][0],
- node->shift, node->count, node->parent);
+ node->shift, node->count, node->exceptional);
for (i = 0; i < RADIX_TREE_MAP_SIZE; i++) {
unsigned long first = index | (i << node->shift);
void *entry = node->slots[i];
if (!entry)
continue;
- if (is_sibling_entry(node, entry)) {
- pr_debug("radix sblng %p offset %ld val %p indices %ld-%ld\n",
- entry, i,
- *(void **)entry_to_node(entry),
- first, last);
+ if (entry == RADIX_TREE_RETRY) {
+ pr_debug("radix retry offset %ld indices %lu-%lu parent %p\n",
+ i, first, last, node);
} else if (!radix_tree_is_internal_node(entry)) {
- pr_debug("radix entry %p offset %ld indices %ld-%ld\n",
- entry, i, first, last);
+ pr_debug("radix entry %p offset %ld indices %lu-%lu parent %p\n",
+ entry, i, first, last, node);
+ } else if (is_sibling_entry(node, entry)) {
+ pr_debug("radix sblng %p offset %ld indices %lu-%lu parent %p val %p\n",
+ entry, i, first, last, node,
+ *(void **)entry_to_node(entry));
} else {
dump_node(entry_to_node(entry), first);
}
{
struct radix_tree_node *node =
container_of(head, struct radix_tree_node, rcu_head);
- int i;
/*
- * must only free zeroed nodes into the slab. radix_tree_shrink
- * can leave us with a non-NULL entry in the first slot, so clear
- * that here to make sure.
+ * Must only free zeroed nodes into the slab. We can be left with
+ * non-NULL entries by radix_tree_free_nodes, so clear the entries
+ * and tags here.
*/
- for (i = 0; i < RADIX_TREE_MAX_TAGS; i++)
- tag_clear(node, i, 0);
-
- node->slots[0] = NULL;
- node->count = 0;
+ memset(node->slots, 0, sizeof(node->slots));
+ memset(node->tags, 0, sizeof(node->tags));
+ INIT_LIST_HEAD(&node->private_list);
kmem_cache_free(radix_tree_node_cachep, node);
}
* To make use of this facility, the radix tree must be initialised without
* __GFP_DIRECT_RECLAIM being passed to INIT_RADIX_TREE().
*/
-static int __radix_tree_preload(gfp_t gfp_mask, int nr)
+static int __radix_tree_preload(gfp_t gfp_mask, unsigned nr)
{
struct radix_tree_preload *rtp;
struct radix_tree_node *node;
}
EXPORT_SYMBOL(radix_tree_maybe_preload);
+#ifdef CONFIG_RADIX_TREE_MULTIORDER
+/*
+ * Preload with enough objects to ensure that we can split a single entry
+ * of order @old_order into many entries of size @new_order
+ */
+int radix_tree_split_preload(unsigned int old_order, unsigned int new_order,
+ gfp_t gfp_mask)
+{
+ unsigned top = 1 << (old_order % RADIX_TREE_MAP_SHIFT);
+ unsigned layers = (old_order / RADIX_TREE_MAP_SHIFT) -
+ (new_order / RADIX_TREE_MAP_SHIFT);
+ unsigned nr = 0;
+
+ WARN_ON_ONCE(!gfpflags_allow_blocking(gfp_mask));
+ BUG_ON(new_order >= old_order);
+
+ while (layers--)
+ nr = nr * RADIX_TREE_MAP_SIZE + 1;
+ return __radix_tree_preload(gfp_mask, top * nr);
+}
+#endif
+
/*
* The same as function above, but preload number of nodes required to insert
* (1 << order) continuous naturally-aligned elements.
return __radix_tree_preload(gfp_mask, nr_nodes);
}
-/*
- * The maximum index which can be stored in a radix tree
- */
-static inline unsigned long shift_maxindex(unsigned int shift)
-{
- return (RADIX_TREE_MAP_SIZE << shift) - 1;
-}
-
-static inline unsigned long node_maxindex(struct radix_tree_node *node)
-{
- return shift_maxindex(node->shift);
-}
-
static unsigned radix_tree_load_root(struct radix_tree_root *root,
struct radix_tree_node **nodep, unsigned long *maxindex)
{
node->offset = 0;
node->count = 1;
node->parent = NULL;
- if (radix_tree_is_internal_node(slot))
+ if (radix_tree_is_internal_node(slot)) {
entry_to_node(slot)->parent = node;
+ } else {
+ /* Moving an exceptional root->rnode to a node */
+ if (radix_tree_exceptional_entry(slot))
+ node->exceptional = 1;
+ }
node->slots[0] = slot;
slot = node_to_entry(node);
rcu_assign_pointer(root->rnode, slot);
return maxshift + RADIX_TREE_MAP_SHIFT;
}
+/**
+ * radix_tree_shrink - shrink radix tree to minimum height
+ * @root radix tree root
+ */
+static inline void radix_tree_shrink(struct radix_tree_root *root,
+ radix_tree_update_node_t update_node,
+ void *private)
+{
+ for (;;) {
+ struct radix_tree_node *node = root->rnode;
+ struct radix_tree_node *child;
+
+ if (!radix_tree_is_internal_node(node))
+ break;
+ node = entry_to_node(node);
+
+ /*
+ * The candidate node has more than one child, or its child
+ * is not at the leftmost slot, or the child is a multiorder
+ * entry, we cannot shrink.
+ */
+ if (node->count != 1)
+ break;
+ child = node->slots[0];
+ if (!child)
+ break;
+ if (!radix_tree_is_internal_node(child) && node->shift)
+ break;
+
+ if (radix_tree_is_internal_node(child))
+ entry_to_node(child)->parent = NULL;
+
+ /*
+ * We don't need rcu_assign_pointer(), since we are simply
+ * moving the node from one part of the tree to another: if it
+ * was safe to dereference the old pointer to it
+ * (node->slots[0]), it will be safe to dereference the new
+ * one (root->rnode) as far as dependent read barriers go.
+ */
+ root->rnode = child;
+
+ /*
+ * We have a dilemma here. The node's slot[0] must not be
+ * NULLed in case there are concurrent lookups expecting to
+ * find the item. However if this was a bottom-level node,
+ * then it may be subject to the slot pointer being visible
+ * to callers dereferencing it. If item corresponding to
+ * slot[0] is subsequently deleted, these callers would expect
+ * their slot to become empty sooner or later.
+ *
+ * For example, lockless pagecache will look up a slot, deref
+ * the page pointer, and if the page has 0 refcount it means it
+ * was concurrently deleted from pagecache so try the deref
+ * again. Fortunately there is already a requirement for logic
+ * to retry the entire slot lookup -- the indirect pointer
+ * problem (replacing direct root node with an indirect pointer
+ * also results in a stale slot). So tag the slot as indirect
+ * to force callers to retry.
+ */
+ node->count = 0;
+ if (!radix_tree_is_internal_node(child)) {
+ node->slots[0] = RADIX_TREE_RETRY;
+ if (update_node)
+ update_node(node, private);
+ }
+
+ radix_tree_node_free(node);
+ }
+}
+
+static void delete_node(struct radix_tree_root *root,
+ struct radix_tree_node *node,
+ radix_tree_update_node_t update_node, void *private)
+{
+ do {
+ struct radix_tree_node *parent;
+
+ if (node->count) {
+ if (node == entry_to_node(root->rnode))
+ radix_tree_shrink(root, update_node, private);
+ return;
+ }
+
+ parent = node->parent;
+ if (parent) {
+ parent->slots[node->offset] = NULL;
+ parent->count--;
+ } else {
+ root_tag_clear_all(root);
+ root->rnode = NULL;
+ }
+
+ radix_tree_node_free(node);
+
+ node = parent;
+ } while (node);
+}
+
/**
* __radix_tree_create - create a slot in a radix tree
* @root: radix tree root
shift = radix_tree_load_root(root, &child, &maxindex);
/* Make sure the tree is high enough. */
+ if (order > 0 && max == ((1UL << order) - 1))
+ max++;
if (max > maxindex) {
int error = radix_tree_extend(root, max, shift);
if (error < 0)
return error;
shift = error;
child = root->rnode;
- if (order == shift)
- shift += RADIX_TREE_MAP_SHIFT;
}
while (shift > order) {
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)
slot = &node->slots[offset];
}
+ if (nodep)
+ *nodep = node;
+ if (slotp)
+ *slotp = slot;
+ return 0;
+}
+
#ifdef CONFIG_RADIX_TREE_MULTIORDER
- /* Insert pointers to the canonical entry */
- if (order > shift) {
- unsigned i, n = 1 << (order - shift);
+/*
+ * Free any nodes below this node. The tree is presumed to not need
+ * shrinking, and any user data in the tree is presumed to not need a
+ * destructor called on it. If we need to add a destructor, we can
+ * add that functionality later. Note that we may not clear tags or
+ * slots from the tree as an RCU walker may still have a pointer into
+ * this subtree. We could replace the entries with RADIX_TREE_RETRY,
+ * but we'll still have to clear those in rcu_free.
+ */
+static void radix_tree_free_nodes(struct radix_tree_node *node)
+{
+ unsigned offset = 0;
+ struct radix_tree_node *child = entry_to_node(node);
+
+ for (;;) {
+ void *entry = child->slots[offset];
+ if (radix_tree_is_internal_node(entry) &&
+ !is_sibling_entry(child, entry)) {
+ child = entry_to_node(entry);
+ offset = 0;
+ continue;
+ }
+ offset++;
+ while (offset == RADIX_TREE_MAP_SIZE) {
+ struct radix_tree_node *old = child;
+ offset = child->offset + 1;
+ child = child->parent;
+ radix_tree_node_free(old);
+ if (old == entry_to_node(node))
+ return;
+ }
+ }
+}
+
+static inline int insert_entries(struct radix_tree_node *node, void **slot,
+ void *item, unsigned order, bool replace)
+{
+ struct radix_tree_node *child;
+ unsigned i, n, tag, offset, tags = 0;
+
+ if (node) {
+ if (order > node->shift)
+ n = 1 << (order - node->shift);
+ else
+ n = 1;
+ offset = get_slot_offset(node, slot);
+ } else {
+ n = 1;
+ offset = 0;
+ }
+
+ if (n > 1) {
offset = offset & ~(n - 1);
slot = &node->slots[offset];
- child = node_to_entry(slot);
- for (i = 0; i < n; i++) {
- if (slot[i])
+ }
+ child = node_to_entry(slot);
+
+ for (i = 0; i < n; i++) {
+ if (slot[i]) {
+ if (replace) {
+ node->count--;
+ for (tag = 0; tag < RADIX_TREE_MAX_TAGS; tag++)
+ if (tag_get(node, tag, offset + i))
+ tags |= 1 << tag;
+ } else
return -EEXIST;
}
+ }
- for (i = 1; i < n; i++) {
+ for (i = 0; i < n; i++) {
+ struct radix_tree_node *old = slot[i];
+ if (i) {
rcu_assign_pointer(slot[i], child);
- node->count++;
+ for (tag = 0; tag < RADIX_TREE_MAX_TAGS; tag++)
+ if (tags & (1 << tag))
+ tag_clear(node, tag, offset + i);
+ } else {
+ rcu_assign_pointer(slot[i], item);
+ for (tag = 0; tag < RADIX_TREE_MAX_TAGS; tag++)
+ if (tags & (1 << tag))
+ tag_set(node, tag, offset);
}
+ if (radix_tree_is_internal_node(old) &&
+ !is_sibling_entry(node, old) &&
+ (old != RADIX_TREE_RETRY))
+ radix_tree_free_nodes(old);
+ if (radix_tree_exceptional_entry(old))
+ node->exceptional--;
}
-#endif
-
- if (nodep)
- *nodep = node;
- if (slotp)
- *slotp = slot;
- return 0;
+ if (node) {
+ node->count += n;
+ if (radix_tree_exceptional_entry(item))
+ node->exceptional += n;
+ }
+ return n;
+}
+#else
+static inline int insert_entries(struct radix_tree_node *node, void **slot,
+ void *item, unsigned order, bool replace)
+{
+ if (*slot)
+ return -EEXIST;
+ rcu_assign_pointer(*slot, item);
+ if (node) {
+ node->count++;
+ if (radix_tree_exceptional_entry(item))
+ node->exceptional++;
+ }
+ return 1;
}
+#endif
/**
* __radix_tree_insert - insert into a radix tree
error = __radix_tree_create(root, index, order, &node, &slot);
if (error)
return error;
- if (*slot != NULL)
- return -EEXIST;
- rcu_assign_pointer(*slot, item);
+
+ error = insert_entries(node, slot, item, order, false);
+ if (error < 0)
+ return error;
if (node) {
unsigned offset = get_slot_offset(node, slot);
- node->count++;
BUG_ON(tag_get(node, 0, offset));
BUG_ON(tag_get(node, 1, offset));
BUG_ON(tag_get(node, 2, offset));
}
EXPORT_SYMBOL(radix_tree_lookup);
-/**
- * radix_tree_tag_set - set a tag on a radix tree node
- * @root: radix tree root
- * @index: index key
- * @tag: tag index
- *
- * Set the search tag (which must be < RADIX_TREE_MAX_TAGS)
- * corresponding to @index in the radix tree. From
- * the root all the way down to the leaf node.
- *
- * Returns the address of the tagged item. Setting a tag on a not-present
- * item is a bug.
- */
-void *radix_tree_tag_set(struct radix_tree_root *root,
- unsigned long index, unsigned int tag)
+static inline int slot_count(struct radix_tree_node *node,
+ void **slot)
{
- struct radix_tree_node *node, *parent;
- unsigned long maxindex;
+ int n = 1;
+#ifdef CONFIG_RADIX_TREE_MULTIORDER
+ void *ptr = node_to_entry(slot);
+ unsigned offset = get_slot_offset(node, slot);
+ int i;
- radix_tree_load_root(root, &node, &maxindex);
- BUG_ON(index > maxindex);
+ for (i = 1; offset + i < RADIX_TREE_MAP_SIZE; i++) {
+ if (node->slots[offset + i] != ptr)
+ break;
+ n++;
+ }
+#endif
+ return n;
+}
- while (radix_tree_is_internal_node(node)) {
- unsigned offset;
+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 count, exceptional;
- parent = entry_to_node(node);
- offset = radix_tree_descend(parent, &node, index);
- BUG_ON(!node);
+ WARN_ON_ONCE(radix_tree_is_internal_node(item));
- if (!tag_get(parent, tag, offset))
- tag_set(parent, tag, offset);
- }
+ count = !!item - !!old;
+ exceptional = !!radix_tree_exceptional_entry(item) -
+ !!radix_tree_exceptional_entry(old);
- /* set the root's tag bit */
- if (!root_tag_get(root, tag))
- root_tag_set(root, tag);
+ WARN_ON_ONCE(warn_typeswitch && (count || exceptional));
- return node;
+ if (node) {
+ node->count += count;
+ if (exceptional) {
+ exceptional *= slot_count(node, slot);
+ node->exceptional += exceptional;
+ }
+ }
+
+ rcu_assign_pointer(*slot, item);
}
-EXPORT_SYMBOL(radix_tree_tag_set);
-static void node_tag_clear(struct radix_tree_root *root,
- struct radix_tree_node *node,
- unsigned int tag, unsigned int offset)
+static inline void delete_sibling_entries(struct radix_tree_node *node,
+ void **slot)
{
- while (node) {
- if (!tag_get(node, tag, offset))
- return;
- tag_clear(node, tag, offset);
- if (any_tag_set(node, tag))
- return;
+#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;
- offset = node->offset;
- node = node->parent;
+ 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--;
}
-
- /* clear the root's tag bit */
- if (root_tag_get(root, tag))
- root_tag_clear(root, tag);
+#endif
+}
+
+/**
+ * __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.
+ * @update_node: callback for changing leaf nodes
+ * @private: private data to pass to @update_node
+ *
+ * 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,
+ 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
+ * node unless the slot is root->rnode.
+ */
+ replace_slot(root, node, slot, item,
+ !node && slot != (void **)&root->rnode);
+
+ if (!node)
+ return;
+
+ if (update_node)
+ update_node(node, private);
+
+ delete_node(root, node, update_node, private);
+}
+
+/**
+ * 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 or
+ * deleting, use __radix_tree_lookup() and __radix_tree_replace() or
+ * radix_tree_iter_replace().
+ */
+void radix_tree_replace_slot(struct radix_tree_root *root,
+ void **slot, void *item)
+{
+ replace_slot(root, NULL, slot, item, true);
+}
+
+/**
+ * radix_tree_iter_replace - 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_split() and radix_tree_for_each_slot().
+ * Caller must hold tree write locked across split and replacement.
+ */
+void radix_tree_iter_replace(struct radix_tree_root *root,
+ const struct radix_tree_iter *iter, void **slot, void *item)
+{
+ __radix_tree_replace(root, iter->node, slot, item, NULL, NULL);
+}
+
+#ifdef CONFIG_RADIX_TREE_MULTIORDER
+/**
+ * radix_tree_join - replace multiple entries with one multiorder entry
+ * @root: radix tree root
+ * @index: an index inside the new entry
+ * @order: order of the new entry
+ * @item: new entry
+ *
+ * Call this function to replace several entries with one larger entry.
+ * The existing entries are presumed to not need freeing as a result of
+ * this call.
+ *
+ * The replacement entry will have all the tags set on it that were set
+ * on any of the entries it is replacing.
+ */
+int radix_tree_join(struct radix_tree_root *root, unsigned long index,
+ unsigned order, void *item)
+{
+ struct radix_tree_node *node;
+ void **slot;
+ int error;
+
+ BUG_ON(radix_tree_is_internal_node(item));
+
+ error = __radix_tree_create(root, index, order, &node, &slot);
+ if (!error)
+ error = insert_entries(node, slot, item, order, true);
+ if (error > 0)
+ error = 0;
+
+ return error;
+}
+
+/**
+ * radix_tree_split - Split an entry into smaller entries
+ * @root: radix tree root
+ * @index: An index within the large entry
+ * @order: Order of new entries
+ *
+ * Call this function as the first step in replacing a multiorder entry
+ * with several entries of lower order. After this function returns,
+ * loop over the relevant portion of the tree using radix_tree_for_each_slot()
+ * and call radix_tree_iter_replace() to set up each new entry.
+ *
+ * The tags from this entry are replicated to all the new entries.
+ *
+ * The radix tree should be locked against modification during the entire
+ * replacement operation. Lock-free lookups will see RADIX_TREE_RETRY which
+ * should prompt RCU walkers to restart the lookup from the root.
+ */
+int radix_tree_split(struct radix_tree_root *root, unsigned long index,
+ unsigned order)
+{
+ struct radix_tree_node *parent, *node, *child;
+ void **slot;
+ unsigned int offset, end;
+ unsigned n, tag, tags = 0;
+
+ if (!__radix_tree_lookup(root, index, &parent, &slot))
+ return -ENOENT;
+ if (!parent)
+ return -ENOENT;
+
+ offset = get_slot_offset(parent, slot);
+
+ for (tag = 0; tag < RADIX_TREE_MAX_TAGS; tag++)
+ if (tag_get(parent, tag, offset))
+ tags |= 1 << tag;
+
+ for (end = offset + 1; end < RADIX_TREE_MAP_SIZE; end++) {
+ if (!is_sibling_entry(parent, parent->slots[end]))
+ break;
+ for (tag = 0; tag < RADIX_TREE_MAX_TAGS; tag++)
+ if (tags & (1 << tag))
+ tag_set(parent, tag, end);
+ /* rcu_assign_pointer ensures tags are set before RETRY */
+ rcu_assign_pointer(parent->slots[end], RADIX_TREE_RETRY);
+ }
+ rcu_assign_pointer(parent->slots[offset], RADIX_TREE_RETRY);
+ parent->exceptional -= (end - offset);
+
+ if (order == parent->shift)
+ return 0;
+ if (order > parent->shift) {
+ while (offset < end)
+ offset += insert_entries(parent, &parent->slots[offset],
+ RADIX_TREE_RETRY, order, true);
+ return 0;
+ }
+
+ node = parent;
+
+ for (;;) {
+ if (node->shift > order) {
+ child = radix_tree_node_alloc(root);
+ 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);
+ for (tag = 0; tag < RADIX_TREE_MAX_TAGS; tag++)
+ if (tags & (1 << tag))
+ tag_set(node, tag, offset);
+ }
+
+ node = child;
+ offset = 0;
+ continue;
+ }
+
+ n = insert_entries(node, &node->slots[offset],
+ RADIX_TREE_RETRY, order, false);
+ BUG_ON(n > RADIX_TREE_MAP_SIZE);
+
+ for (tag = 0; tag < RADIX_TREE_MAX_TAGS; tag++)
+ if (tags & (1 << tag))
+ tag_set(node, tag, offset);
+ offset += n;
+
+ while (offset == RADIX_TREE_MAP_SIZE) {
+ if (node == parent)
+ break;
+ offset = node->offset;
+ child = node;
+ node = node->parent;
+ rcu_assign_pointer(node->slots[offset],
+ node_to_entry(child));
+ offset++;
+ }
+ if ((node == parent) && (offset == end))
+ return 0;
+ }
+
+ nomem:
+ /* Shouldn't happen; did user forget to preload? */
+ /* TODO: free all the allocated nodes */
+ WARN_ON(1);
+ return -ENOMEM;
+}
+#endif
+
+/**
+ * radix_tree_tag_set - set a tag on a radix tree node
+ * @root: radix tree root
+ * @index: index key
+ * @tag: tag index
+ *
+ * Set the search tag (which must be < RADIX_TREE_MAX_TAGS)
+ * corresponding to @index in the radix tree. From
+ * the root all the way down to the leaf node.
+ *
+ * Returns the address of the tagged item. Setting a tag on a not-present
+ * item is a bug.
+ */
+void *radix_tree_tag_set(struct radix_tree_root *root,
+ unsigned long index, unsigned int tag)
+{
+ struct radix_tree_node *node, *parent;
+ unsigned long maxindex;
+
+ radix_tree_load_root(root, &node, &maxindex);
+ BUG_ON(index > maxindex);
+
+ while (radix_tree_is_internal_node(node)) {
+ unsigned offset;
+
+ parent = entry_to_node(node);
+ offset = radix_tree_descend(parent, &node, index);
+ BUG_ON(!node);
+
+ if (!tag_get(parent, tag, offset))
+ tag_set(parent, tag, offset);
+ }
+
+ /* set the root's tag bit */
+ if (!root_tag_get(root, tag))
+ root_tag_set(root, tag);
+
+ return node;
+}
+EXPORT_SYMBOL(radix_tree_tag_set);
+
+static void node_tag_clear(struct radix_tree_root *root,
+ struct radix_tree_node *node,
+ unsigned int tag, unsigned int offset)
+{
+ while (node) {
+ if (!tag_get(node, tag, offset))
+ return;
+ tag_clear(node, tag, offset);
+ if (any_tag_set(node, tag))
+ return;
+
+ offset = node->offset;
+ node = node->parent;
+ }
+
+ /* clear the root's tag bit */
+ if (root_tag_get(root, tag))
+ root_tag_clear(root, tag);
+}
+
+static void node_tag_set(struct radix_tree_root *root,
+ struct radix_tree_node *node,
+ unsigned int tag, unsigned int offset)
+{
+ while (node) {
+ if (tag_get(node, tag, offset))
+ return;
+ tag_set(node, tag, offset);
+ offset = node->offset;
+ node = node->parent;
+ }
+
+ if (!root_tag_get(root, tag))
+ root_tag_set(root, tag);
+}
+
+/**
+ * radix_tree_iter_tag_set - set a tag on the current iterator entry
+ * @root: radix tree root
+ * @iter: iterator state
+ * @tag: tag to set
+ */
+void radix_tree_iter_tag_set(struct radix_tree_root *root,
+ const struct radix_tree_iter *iter, unsigned int tag)
+{
+ node_tag_set(root, iter->node, tag, iter_offset(iter));
}
/**
#endif
}
+/* Construct iter->tags bit-mask from node->tags[tag] array */
+static void set_iter_tags(struct radix_tree_iter *iter,
+ struct radix_tree_node *node, unsigned offset,
+ unsigned tag)
+{
+ unsigned tag_long = offset / BITS_PER_LONG;
+ unsigned tag_bit = offset % BITS_PER_LONG;
+
+ iter->tags = node->tags[tag][tag_long] >> tag_bit;
+
+ /* This never happens if RADIX_TREE_TAG_LONGS == 1 */
+ if (tag_long < RADIX_TREE_TAG_LONGS - 1) {
+ /* Pick tags from next element */
+ if (tag_bit)
+ iter->tags |= node->tags[tag][tag_long + 1] <<
+ (BITS_PER_LONG - tag_bit);
+ /* Clip chunk size, here only BITS_PER_LONG tags */
+ iter->next_index = __radix_tree_iter_add(iter, BITS_PER_LONG);
+ }
+}
+
+#ifdef CONFIG_RADIX_TREE_MULTIORDER
+static void **skip_siblings(struct radix_tree_node **nodep,
+ void **slot, struct radix_tree_iter *iter)
+{
+ void *sib = node_to_entry(slot - 1);
+
+ while (iter->index < iter->next_index) {
+ *nodep = rcu_dereference_raw(*slot);
+ if (*nodep && *nodep != sib)
+ return slot;
+ slot++;
+ iter->index = __radix_tree_iter_add(iter, 1);
+ iter->tags >>= 1;
+ }
+
+ *nodep = NULL;
+ return NULL;
+}
+
+void ** __radix_tree_next_slot(void **slot, struct radix_tree_iter *iter,
+ unsigned flags)
+{
+ unsigned tag = flags & RADIX_TREE_ITER_TAG_MASK;
+ struct radix_tree_node *node = rcu_dereference_raw(*slot);
+
+ slot = skip_siblings(&node, slot, iter);
+
+ while (radix_tree_is_internal_node(node)) {
+ unsigned offset;
+ unsigned long next_index;
+
+ if (node == RADIX_TREE_RETRY)
+ return slot;
+ node = entry_to_node(node);
+ iter->node = node;
+ iter->shift = node->shift;
+
+ if (flags & RADIX_TREE_ITER_TAGGED) {
+ offset = radix_tree_find_next_bit(node, tag, 0);
+ if (offset == RADIX_TREE_MAP_SIZE)
+ return NULL;
+ slot = &node->slots[offset];
+ iter->index = __radix_tree_iter_add(iter, offset);
+ set_iter_tags(iter, node, offset, tag);
+ node = rcu_dereference_raw(*slot);
+ } else {
+ offset = 0;
+ slot = &node->slots[0];
+ for (;;) {
+ node = rcu_dereference_raw(*slot);
+ if (node)
+ break;
+ slot++;
+ offset++;
+ if (offset == RADIX_TREE_MAP_SIZE)
+ return NULL;
+ }
+ iter->index = __radix_tree_iter_add(iter, offset);
+ }
+ if ((flags & RADIX_TREE_ITER_CONTIG) && (offset > 0))
+ goto none;
+ next_index = (iter->index | shift_maxindex(iter->shift)) + 1;
+ if (next_index < iter->next_index)
+ iter->next_index = next_index;
+ }
+
+ return slot;
+ none:
+ iter->next_index = 0;
+ return NULL;
+}
+EXPORT_SYMBOL(__radix_tree_next_slot);
+#else
+static void **skip_siblings(struct radix_tree_node **nodep,
+ void **slot, struct radix_tree_iter *iter)
+{
+ return slot;
+}
+#endif
+
+void **radix_tree_iter_resume(void **slot, struct radix_tree_iter *iter)
+{
+ struct radix_tree_node *node;
+
+ slot++;
+ iter->index = __radix_tree_iter_add(iter, 1);
+ node = rcu_dereference_raw(*slot);
+ skip_siblings(&node, slot, iter);
+ iter->next_index = iter->index;
+ iter->tags = 0;
+ return NULL;
+}
+EXPORT_SYMBOL(radix_tree_iter_resume);
+
/**
* radix_tree_next_chunk - find next chunk of slots for iteration
*
* because RADIX_TREE_MAP_SHIFT < BITS_PER_LONG.
*
* This condition also used by radix_tree_next_slot() to stop
- * contiguous iterating, and forbid swithing to the next chunk.
+ * contiguous iterating, and forbid switching to the next chunk.
*/
index = iter->next_index;
if (!index && iter->index)
iter->index = index;
iter->next_index = maxindex + 1;
iter->tags = 1;
+ iter->node = NULL;
__set_iter_shift(iter, 0);
return (void **)&root->rnode;
}
return NULL;
if (flags & RADIX_TREE_ITER_TAGGED)
- offset = radix_tree_find_next_bit(
- node->tags[tag],
- RADIX_TREE_MAP_SIZE,
+ offset = radix_tree_find_next_bit(node, tag,
offset + 1);
else
while (++offset < RADIX_TREE_MAP_SIZE) {
child = rcu_dereference_raw(node->slots[offset]);
}
- if ((child == NULL) || (child == RADIX_TREE_RETRY))
+ if (!child)
goto restart;
+ if (child == RADIX_TREE_RETRY)
+ break;
} while (radix_tree_is_internal_node(child));
/* Update the iterator state */
iter->index = (index &~ node_maxindex(node)) | (offset << node->shift);
iter->next_index = (index | node_maxindex(node)) + 1;
+ iter->node = node;
__set_iter_shift(iter, node->shift);
- /* Construct iter->tags bit-mask from node->tags[tag] array */
- if (flags & RADIX_TREE_ITER_TAGGED) {
- unsigned tag_long, tag_bit;
-
- tag_long = offset / BITS_PER_LONG;
- tag_bit = offset % BITS_PER_LONG;
- iter->tags = node->tags[tag][tag_long] >> tag_bit;
- /* This never happens if RADIX_TREE_TAG_LONGS == 1 */
- if (tag_long < RADIX_TREE_TAG_LONGS - 1) {
- /* Pick tags from next element */
- if (tag_bit)
- iter->tags |= node->tags[tag][tag_long + 1] <<
- (BITS_PER_LONG - tag_bit);
- /* Clip chunk size, here only BITS_PER_LONG tags */
- iter->next_index = index + BITS_PER_LONG;
- }
- }
+ if (flags & RADIX_TREE_ITER_TAGGED)
+ set_iter_tags(iter, node, offset, tag);
return node->slots + offset;
}
EXPORT_SYMBOL(radix_tree_next_chunk);
-/**
- * radix_tree_range_tag_if_tagged - for each item in given range set given
- * tag if item has another tag set
- * @root: radix tree root
- * @first_indexp: pointer to a starting index of a range to scan
- * @last_index: last index of a range to scan
- * @nr_to_tag: maximum number items to tag
- * @iftag: tag index to test
- * @settag: tag index to set if tested tag is set
- *
- * This function scans range of radix tree from first_index to last_index
- * (inclusive). For each item in the range if iftag is set, the function sets
- * also settag. The function stops either after tagging nr_to_tag items or
- * after reaching last_index.
- *
- * The tags must be set from the leaf level only and propagated back up the
- * path to the root. We must do this so that we resolve the full path before
- * setting any tags on intermediate nodes. If we set tags as we descend, then
- * we can get to the leaf node and find that the index that has the iftag
- * set is outside the range we are scanning. This reults in dangling tags and
- * can lead to problems with later tag operations (e.g. livelocks on lookups).
- *
- * The function returns the number of leaves where the tag was set and sets
- * *first_indexp to the first unscanned index.
- * WARNING! *first_indexp can wrap if last_index is ULONG_MAX. Caller must
- * be prepared to handle that.
- */
-unsigned long radix_tree_range_tag_if_tagged(struct radix_tree_root *root,
- unsigned long *first_indexp, unsigned long last_index,
- unsigned long nr_to_tag,
- unsigned int iftag, unsigned int settag)
-{
- struct radix_tree_node *parent, *node, *child;
- unsigned long maxindex;
- unsigned long tagged = 0;
- unsigned long index = *first_indexp;
-
- radix_tree_load_root(root, &child, &maxindex);
- last_index = min(last_index, maxindex);
- if (index > last_index)
- return 0;
- if (!nr_to_tag)
- return 0;
- if (!root_tag_get(root, iftag)) {
- *first_indexp = last_index + 1;
- return 0;
- }
- if (!radix_tree_is_internal_node(child)) {
- *first_indexp = last_index + 1;
- root_tag_set(root, settag);
- return 1;
- }
-
- node = entry_to_node(child);
-
- for (;;) {
- unsigned offset = radix_tree_descend(node, &child, index);
- if (!child)
- goto next;
- if (!tag_get(node, iftag, offset))
- goto next;
- /* Sibling slots never have tags set on them */
- if (radix_tree_is_internal_node(child)) {
- node = entry_to_node(child);
- continue;
- }
-
- /* tag the leaf */
- tagged++;
- tag_set(node, settag, offset);
-
- /* walk back up the path tagging interior nodes */
- parent = node;
- for (;;) {
- offset = parent->offset;
- parent = parent->parent;
- if (!parent)
- break;
- /* stop if we find a node with the tag already set */
- if (tag_get(parent, settag, offset))
- break;
- tag_set(parent, settag, offset);
- }
- next:
- /* Go to next entry in node */
- index = ((index >> node->shift) + 1) << node->shift;
- /* Overflow can happen when last_index is ~0UL... */
- if (index > last_index || !index)
- break;
- offset = (index >> node->shift) & RADIX_TREE_MAP_MASK;
- while (offset == 0) {
- /*
- * We've fully scanned this node. Go up. Because
- * last_index is guaranteed to be in the tree, what
- * we do below cannot wander astray.
- */
- node = node->parent;
- offset = (index >> node->shift) & RADIX_TREE_MAP_MASK;
- }
- if (is_sibling_entry(node, node->slots[offset]))
- goto next;
- if (tagged >= nr_to_tag)
- break;
- }
- /*
- * We need not to tag the root tag if there is no tag which is set with
- * settag within the range from *first_indexp to last_index.
- */
- if (tagged > 0)
- root_tag_set(root, settag);
- *first_indexp = index;
-
- return tagged;
-}
-EXPORT_SYMBOL(radix_tree_range_tag_if_tagged);
-
/**
* radix_tree_gang_lookup - perform multiple lookup on a radix tree
* @root: radix tree root
}
EXPORT_SYMBOL(radix_tree_gang_lookup_tag_slot);
-#if defined(CONFIG_SHMEM) && defined(CONFIG_SWAP)
-#include <linux/sched.h> /* for cond_resched() */
-
-struct locate_info {
- unsigned long found_index;
- bool stop;
-};
-
-/*
- * This linear search is at present only useful to shmem_unuse_inode().
- */
-static unsigned long __locate(struct radix_tree_node *slot, void *item,
- unsigned long index, struct locate_info *info)
-{
- unsigned long i;
-
- do {
- unsigned int shift = slot->shift;
-
- for (i = (index >> shift) & RADIX_TREE_MAP_MASK;
- i < RADIX_TREE_MAP_SIZE;
- i++, index += (1UL << shift)) {
- struct radix_tree_node *node =
- rcu_dereference_raw(slot->slots[i]);
- if (node == RADIX_TREE_RETRY)
- goto out;
- if (!radix_tree_is_internal_node(node)) {
- if (node == item) {
- info->found_index = index;
- info->stop = true;
- goto out;
- }
- continue;
- }
- node = entry_to_node(node);
- if (is_sibling_entry(slot, node))
- continue;
- slot = node;
- break;
- }
- } while (i < RADIX_TREE_MAP_SIZE);
-
-out:
- if ((index == 0) && (i == RADIX_TREE_MAP_SIZE))
- info->stop = true;
- return index;
-}
-
-/**
- * radix_tree_locate_item - search through radix tree for item
- * @root: radix tree root
- * @item: item to be found
- *
- * Returns index where item was found, or -1 if not found.
- * Caller must hold no lock (since this time-consuming function needs
- * to be preemptible), and must check afterwards if item is still there.
- */
-unsigned long radix_tree_locate_item(struct radix_tree_root *root, void *item)
-{
- struct radix_tree_node *node;
- unsigned long max_index;
- unsigned long cur_index = 0;
- struct locate_info info = {
- .found_index = -1,
- .stop = false,
- };
-
- do {
- rcu_read_lock();
- node = rcu_dereference_raw(root->rnode);
- if (!radix_tree_is_internal_node(node)) {
- rcu_read_unlock();
- if (node == item)
- info.found_index = 0;
- break;
- }
-
- node = entry_to_node(node);
-
- max_index = node_maxindex(node);
- if (cur_index > max_index) {
- rcu_read_unlock();
- break;
- }
-
- cur_index = __locate(node, item, cur_index, &info);
- rcu_read_unlock();
- cond_resched();
- } while (!info.stop && cur_index <= max_index);
-
- return info.found_index;
-}
-#else
-unsigned long radix_tree_locate_item(struct radix_tree_root *root, void *item)
-{
- return -1;
-}
-#endif /* CONFIG_SHMEM && CONFIG_SWAP */
-
-/**
- * radix_tree_shrink - shrink radix tree to minimum height
- * @root radix tree root
- */
-static inline bool radix_tree_shrink(struct radix_tree_root *root)
-{
- bool shrunk = false;
-
- for (;;) {
- struct radix_tree_node *node = root->rnode;
- struct radix_tree_node *child;
-
- if (!radix_tree_is_internal_node(node))
- break;
- node = entry_to_node(node);
-
- /*
- * The candidate node has more than one child, or its child
- * is not at the leftmost slot, or the child is a multiorder
- * entry, we cannot shrink.
- */
- if (node->count != 1)
- break;
- child = node->slots[0];
- if (!child)
- break;
- if (!radix_tree_is_internal_node(child) && node->shift)
- break;
-
- if (radix_tree_is_internal_node(child))
- entry_to_node(child)->parent = NULL;
-
- /*
- * We don't need rcu_assign_pointer(), since we are simply
- * moving the node from one part of the tree to another: if it
- * was safe to dereference the old pointer to it
- * (node->slots[0]), it will be safe to dereference the new
- * one (root->rnode) as far as dependent read barriers go.
- */
- root->rnode = child;
-
- /*
- * We have a dilemma here. The node's slot[0] must not be
- * NULLed in case there are concurrent lookups expecting to
- * find the item. However if this was a bottom-level node,
- * then it may be subject to the slot pointer being visible
- * to callers dereferencing it. If item corresponding to
- * slot[0] is subsequently deleted, these callers would expect
- * their slot to become empty sooner or later.
- *
- * For example, lockless pagecache will look up a slot, deref
- * the page pointer, and if the page has 0 refcount it means it
- * was concurrently deleted from pagecache so try the deref
- * again. Fortunately there is already a requirement for logic
- * to retry the entire slot lookup -- the indirect pointer
- * problem (replacing direct root node with an indirect pointer
- * also results in a stale slot). So tag the slot as indirect
- * to force callers to retry.
- */
- if (!radix_tree_is_internal_node(child))
- node->slots[0] = RADIX_TREE_RETRY;
-
- radix_tree_node_free(node);
- shrunk = true;
- }
-
- return shrunk;
-}
-
/**
* __radix_tree_delete_node - try to free node after clearing a slot
* @root: radix tree root
* After clearing the slot at @index in @node from radix tree
* rooted at @root, call this function to attempt freeing the
* node and shrinking the tree.
- *
- * Returns %true if @node was freed, %false otherwise.
*/
-bool __radix_tree_delete_node(struct radix_tree_root *root,
+void __radix_tree_delete_node(struct radix_tree_root *root,
struct radix_tree_node *node)
{
- bool deleted = false;
-
- do {
- struct radix_tree_node *parent;
-
- if (node->count) {
- if (node == entry_to_node(root->rnode))
- deleted |= radix_tree_shrink(root);
- return deleted;
- }
-
- parent = node->parent;
- if (parent) {
- parent->slots[node->offset] = NULL;
- parent->count--;
- } else {
- root_tag_clear_all(root);
- root->rnode = NULL;
- }
-
- radix_tree_node_free(node);
- deleted = true;
-
- node = parent;
- } while (node);
-
- return deleted;
-}
-
-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
+ delete_node(root, node, NULL, NULL);
}
/**
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);
- node->slots[offset] = NULL;
- node->count--;
-
- __radix_tree_delete_node(root, node);
+ __radix_tree_replace(root, node, slot, NULL, NULL, NULL);
return entry;
}
}
}
-static int radix_tree_callback(struct notifier_block *nfb,
- unsigned long action, void *hcpu)
+static int radix_tree_cpu_dead(unsigned int cpu)
{
- int cpu = (long)hcpu;
struct radix_tree_preload *rtp;
struct radix_tree_node *node;
/* Free per-cpu pool of preloaded nodes */
- if (action == CPU_DEAD || action == CPU_DEAD_FROZEN) {
- rtp = &per_cpu(radix_tree_preloads, cpu);
- while (rtp->nr) {
- node = rtp->nodes;
- rtp->nodes = node->private_data;
- kmem_cache_free(radix_tree_node_cachep, node);
- rtp->nr--;
- }
+ rtp = &per_cpu(radix_tree_preloads, cpu);
+ while (rtp->nr) {
+ node = rtp->nodes;
+ rtp->nodes = node->private_data;
+ kmem_cache_free(radix_tree_node_cachep, node);
+ rtp->nr--;
}
- return NOTIFY_OK;
+ return 0;
}
void __init radix_tree_init(void)
{
+ int ret;
radix_tree_node_cachep = kmem_cache_create("radix_tree_node",
sizeof(struct radix_tree_node), 0,
SLAB_PANIC | SLAB_RECLAIM_ACCOUNT,
radix_tree_node_ctor);
radix_tree_init_maxnodes();
- hotcpu_notifier(radix_tree_callback, 0);
+ ret = cpuhp_setup_state_nocalls(CPUHP_RADIX_DEAD, "lib/radix:dead",
+ NULL, radix_tree_cpu_dead);
+ WARN_ON(ret < 0);
}
projects / mirror_ubuntu-zesty-kernel.git / blobdiff