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-rw-r--r--lib/test_xarray.c21
-rw-r--r--lib/xarray.c40
2 files changed, 61 insertions, 0 deletions
diff --git a/lib/test_xarray.c b/lib/test_xarray.c
index d4f97925dbd8..bdd4d7995f79 100644
--- a/lib/test_xarray.c
+++ b/lib/test_xarray.c
@@ -1649,6 +1649,26 @@ static noinline void check_account(struct xarray *xa)
#endif
}
+static noinline void check_get_order(struct xarray *xa)
+{
+ unsigned int max_order = IS_ENABLED(CONFIG_XARRAY_MULTI) ? 20 : 1;
+ unsigned int order;
+ unsigned long i, j;
+
+ for (i = 0; i < 3; i++)
+ XA_BUG_ON(xa, xa_get_order(xa, i) != 0);
+
+ for (order = 0; order < max_order; order++) {
+ for (i = 0; i < 10; i++) {
+ xa_store_order(xa, i << order, order,
+ xa_mk_index(i << order), GFP_KERNEL);
+ for (j = i << order; j < (i + 1) << order; j++)
+ XA_BUG_ON(xa, xa_get_order(xa, j) != order);
+ xa_erase(xa, i << order);
+ }
+ }
+}
+
static noinline void check_destroy(struct xarray *xa)
{
unsigned long index;
@@ -1697,6 +1717,7 @@ static int xarray_checks(void)
check_reserve(&array);
check_reserve(&xa0);
check_multi_store(&array);
+ check_get_order(&array);
check_xa_alloc();
check_find(&array);
check_find_entry(&array);
diff --git a/lib/xarray.c b/lib/xarray.c
index e9e641d3c0c3..f24cb9a43af8 100644
--- a/lib/xarray.c
+++ b/lib/xarray.c
@@ -1592,6 +1592,46 @@ unlock:
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 */
/**

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