xarray: Add xas_create_range
This hopefully temporary function is useful for users who have not yet
been converted to multi-index entries.
Signed-off-by: Matthew Wilcox <[email protected]>
diff --git a/lib/xarray.c b/lib/xarray.c
index 41f8ebc..ff37516 100644
--- a/lib/xarray.c
+++ b/lib/xarray.c
@@ -637,6 +637,56 @@ static void *xas_create(struct xa_state *xas)
return entry;
}
+/**
+ * xas_create_range() - Ensure that stores to this range will succeed
+ * @xas: XArray operation state.
+ *
+ * Creates all of the slots in the range covered by @xas. Sets @xas to
+ * create single-index entries and positions it at the beginning of the
+ * range. This is for the benefit of users which have not yet been
+ * converted to use multi-index entries.
+ */
+void xas_create_range(struct xa_state *xas)
+{
+ unsigned long index = xas->xa_index;
+ unsigned char shift = xas->xa_shift;
+ unsigned char sibs = xas->xa_sibs;
+
+ xas->xa_index |= ((sibs + 1) << shift) - 1;
+ if (xas_is_node(xas) && xas->xa_node->shift == xas->xa_shift)
+ xas->xa_offset |= sibs;
+ xas->xa_shift = 0;
+ xas->xa_sibs = 0;
+
+ for (;;) {
+ xas_create(xas);
+ if (xas_error(xas))
+ goto restore;
+ if (xas->xa_index <= (index | XA_CHUNK_MASK))
+ goto success;
+ xas->xa_index -= XA_CHUNK_SIZE;
+
+ for (;;) {
+ struct xa_node *node = xas->xa_node;
+ xas->xa_node = xa_parent_locked(xas->xa, node);
+ xas->xa_offset = node->offset - 1;
+ if (node->offset != 0)
+ break;
+ }
+ }
+
+restore:
+ xas->xa_shift = shift;
+ xas->xa_sibs = sibs;
+ xas->xa_index = index;
+ return;
+success:
+ xas->xa_index = index;
+ if (xas->xa_node)
+ xas_set_offset(xas);
+}
+EXPORT_SYMBOL_GPL(xas_create_range);
+
static void update_node(struct xa_state *xas, struct xa_node *node,
int count, int values)
{
