*/
static void xas_destroy(struct xa_state *xas)
{
- struct xa_node *node = xas->xa_alloc;
+ struct xa_node *next, *node = xas->xa_alloc;
- if (!node)
- return;
- XA_NODE_BUG_ON(node, !list_empty(&node->private_list));
- kmem_cache_free(radix_tree_node_cachep, node);
- xas->xa_alloc = NULL;
+ while (node) {
+ XA_NODE_BUG_ON(node, !list_empty(&node->private_list));
+ next = rcu_dereference_raw(node->parent);
+ radix_tree_node_rcu_free(&node->rcu_head);
+ xas->xa_alloc = node = next;
+ }
}
/**
xas->xa_alloc = kmem_cache_alloc(radix_tree_node_cachep, gfp);
if (!xas->xa_alloc)
return false;
+ xas->xa_alloc->parent = NULL;
XA_NODE_BUG_ON(xas->xa_alloc, !list_empty(&xas->xa_alloc->private_list));
xas->xa_node = XAS_RESTART;
return true;
}
if (!xas->xa_alloc)
return false;
+ xas->xa_alloc->parent = NULL;
XA_NODE_BUG_ON(xas->xa_alloc, !list_empty(&xas->xa_alloc->private_list));
xas->xa_node = XAS_RESTART;
return true;
/*
* Use this to calculate the maximum index that will need to be created
* in order to add the entry described by @xas. Because we cannot store a
- * multiple-index entry at index 0, the calculation is a little more complex
+ * multi-index entry at index 0, the calculation is a little more complex
* than you might expect.
*/
static unsigned long xas_max(struct xa_state *xas)
}
EXPORT_SYMBOL_GPL(xas_init_marks);
+#ifdef CONFIG_XARRAY_MULTI
+static unsigned int node_get_marks(struct xa_node *node, unsigned int offset)
+{
+ unsigned int marks = 0;
+ xa_mark_t mark = XA_MARK_0;
+
+ for (;;) {
+ if (node_get_mark(node, offset, mark))
+ marks |= 1 << (__force unsigned int)mark;
+ if (mark == XA_MARK_MAX)
+ break;
+ mark_inc(mark);
+ }
+
+ return marks;
+}
+
+static void node_set_marks(struct xa_node *node, unsigned int offset,
+ struct xa_node *child, unsigned int marks)
+{
+ xa_mark_t mark = XA_MARK_0;
+
+ for (;;) {
+ if (marks & (1 << (__force unsigned int)mark)) {
+ node_set_mark(node, offset, mark);
+ if (child)
+ node_mark_all(child, mark);
+ }
+ if (mark == XA_MARK_MAX)
+ break;
+ mark_inc(mark);
+ }
+}
+
+/**
+ * xas_split_alloc() - Allocate memory for splitting an entry.
+ * @xas: XArray operation state.
+ * @entry: New entry which will be stored in the array.
+ * @order: New entry order.
+ * @gfp: Memory allocation flags.
+ *
+ * This function should be called before calling xas_split().
+ * If necessary, it will allocate new nodes (and fill them with @entry)
+ * to prepare for the upcoming split of an entry of @order size into
+ * entries of the order stored in the @xas.
+ *
+ * Context: May sleep if @gfp flags permit.
+ */
+void xas_split_alloc(struct xa_state *xas, void *entry, unsigned int order,
+ gfp_t gfp)
+{
+ unsigned int sibs = (1 << (order % XA_CHUNK_SHIFT)) - 1;
+ unsigned int mask = xas->xa_sibs;
+
+ /* XXX: no support for splitting really large entries yet */
+ if (WARN_ON(xas->xa_shift + 2 * XA_CHUNK_SHIFT < order))
+ goto nomem;
+ if (xas->xa_shift + XA_CHUNK_SHIFT > order)
+ return;
+
+ do {
+ unsigned int i;
+ void *sibling;
+ struct xa_node *node;
+
+ node = kmem_cache_alloc(radix_tree_node_cachep, gfp);
+ if (!node)
+ goto nomem;
+ node->array = xas->xa;
+ for (i = 0; i < XA_CHUNK_SIZE; i++) {
+ if ((i & mask) == 0) {
+ RCU_INIT_POINTER(node->slots[i], entry);
+ sibling = xa_mk_sibling(0);
+ } else {
+ RCU_INIT_POINTER(node->slots[i], sibling);
+ }
+ }
+ RCU_INIT_POINTER(node->parent, xas->xa_alloc);
+ xas->xa_alloc = node;
+ } while (sibs-- > 0);
+
+ return;
+nomem:
+ xas_destroy(xas);
+ xas_set_err(xas, -ENOMEM);
+}
+EXPORT_SYMBOL_GPL(xas_split_alloc);
+
+/**
+ * xas_split() - Split a multi-index entry into smaller entries.
+ * @xas: XArray operation state.
+ * @entry: New entry to store in the array.
+ * @order: New entry order.
+ *
+ * The value in the entry is copied to all the replacement entries.
+ *
+ * Context: Any context. The caller should hold the xa_lock.
+ */
+void xas_split(struct xa_state *xas, void *entry, unsigned int order)
+{
+ unsigned int sibs = (1 << (order % XA_CHUNK_SHIFT)) - 1;
+ unsigned int offset, marks;
+ struct xa_node *node;
+ void *curr = xas_load(xas);
+ int values = 0;
+
+ node = xas->xa_node;
+ if (xas_top(node))
+ return;
+
+ marks = node_get_marks(node, xas->xa_offset);
+
+ offset = xas->xa_offset + sibs;
+ do {
+ if (xas->xa_shift < node->shift) {
+ struct xa_node *child = xas->xa_alloc;
+
+ xas->xa_alloc = rcu_dereference_raw(child->parent);
+ child->shift = node->shift - XA_CHUNK_SHIFT;
+ child->offset = offset;
+ child->count = XA_CHUNK_SIZE;
+ child->nr_values = xa_is_value(entry) ?
+ XA_CHUNK_SIZE : 0;
+ RCU_INIT_POINTER(child->parent, node);
+ node_set_marks(node, offset, child, marks);
+ rcu_assign_pointer(node->slots[offset],
+ xa_mk_node(child));
+ if (xa_is_value(curr))
+ values--;
+ } else {
+ unsigned int canon = offset - xas->xa_sibs;
+
+ node_set_marks(node, canon, NULL, marks);
+ rcu_assign_pointer(node->slots[canon], entry);
+ while (offset > canon)
+ rcu_assign_pointer(node->slots[offset--],
+ xa_mk_sibling(canon));
+ values += (xa_is_value(entry) - xa_is_value(curr)) *
+ (xas->xa_sibs + 1);
+ }
+ } while (offset-- > xas->xa_offset);
+
+ node->nr_values += values;
+}
+EXPORT_SYMBOL_GPL(xas_split);
+#endif
+
/**
* xas_pause() - Pause a walk to drop a lock.
* @xas: XArray operation state.
* @gfp: Memory allocation flags.
*
* After this function returns, loads from this index will return @entry.
- * Storing into an existing multislot entry updates the entry of every index.
+ * Storing into an existing multi-index entry updates the entry of every index.
* The marks associated with @index are unaffected unless @entry is %NULL.
*
* Context: Any context. Takes and releases the xa_lock.
*
* After this function returns, loads from any index between @first and @last,
* inclusive will return @entry.
- * Storing into an existing multislot entry updates the entry of every index.
+ * Storing into an existing multi-index entry updates the entry of every index.
* The marks associated with @index are unaffected unless @entry is %NULL.
*
* Context: Process context. Takes and releases the xa_lock. May sleep
return xas_result(&xas, NULL);
}
EXPORT_SYMBOL(xa_store_range);
+
+/**
+ * xa_get_order() - Get the order of an entry.
+ * @xa: XArray.
+ * @index: Index of the entry.
+ *
+ * Return: A number between 0 and 63 indicating the order of the entry.
+ */
+int xa_get_order(struct xarray *xa, unsigned long index)
+{
+ XA_STATE(xas, xa, index);
+ void *entry;
+ int order = 0;
+
+ rcu_read_lock();
+ entry = xas_load(&xas);
+
+ if (!entry)
+ goto unlock;
+
+ if (!xas.xa_node)
+ goto unlock;
+
+ for (;;) {
+ unsigned int slot = xas.xa_offset + (1 << order);
+
+ if (slot >= XA_CHUNK_SIZE)
+ break;
+ if (!xa_is_sibling(xas.xa_node->slots[slot]))
+ break;
+ order++;
+ }
+
+ order += xas.xa_node->shift;
+unlock:
+ rcu_read_unlock();
+
+ return order;
+}
+EXPORT_SYMBOL(xa_get_order);
#endif /* CONFIG_XARRAY_MULTI */
/**
projects / linux-2.6-microblaze.git / blobdiff