diff --git a/lib/test_xarray.c b/lib/test_xarray.c
new file mode 100644
index 0000000..7df4f7f
--- /dev/null
+++ b/lib/test_xarray.c
@@ -0,0 +1,1622 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * test_xarray.c: Test the XArray API
+ * Copyright (c) 2017-2018 Microsoft Corporation
+ * Author: Matthew Wilcox <willy@infradead.org>
+ */
+
+#include <linux/xarray.h>
+#include <linux/module.h>
+
+static unsigned int tests_run;
+static unsigned int tests_passed;
+
+#ifndef XA_DEBUG
+# ifdef __KERNEL__
+void xa_dump(const struct xarray *xa) { }
+# endif
+#undef XA_BUG_ON
+#define XA_BUG_ON(xa, x) do {					\
+	tests_run++;						\
+	if (x) {						\
+		printk("BUG at %s:%d\n", __func__, __LINE__);	\
+		xa_dump(xa);					\
+		dump_stack();					\
+	} else {						\
+		tests_passed++;					\
+	}							\
+} while (0)
+#endif
+
+static void *xa_mk_index(unsigned long index)
+{
+	return xa_mk_value(index & LONG_MAX);
+}
+
+static void *xa_store_index(struct xarray *xa, unsigned long index, gfp_t gfp)
+{
+	return xa_store(xa, index, xa_mk_index(index), gfp);
+}
+
+static void xa_insert_index(struct xarray *xa, unsigned long index)
+{
+	XA_BUG_ON(xa, xa_insert(xa, index, xa_mk_index(index),
+				GFP_KERNEL) != 0);
+}
+
+static void xa_alloc_index(struct xarray *xa, unsigned long index, gfp_t gfp)
+{
+	u32 id;
+
+	XA_BUG_ON(xa, xa_alloc(xa, &id, xa_mk_index(index), xa_limit_32b,
+				gfp) != 0);
+	XA_BUG_ON(xa, id != index);
+}
+
+static void xa_erase_index(struct xarray *xa, unsigned long index)
+{
+	XA_BUG_ON(xa, xa_erase(xa, index) != xa_mk_index(index));
+	XA_BUG_ON(xa, xa_load(xa, index) != NULL);
+}
+
+/*
+ * If anyone needs this, please move it to xarray.c.  We have no current
+ * users outside the test suite because all current multislot users want
+ * to use the advanced API.
+ */
+static void *xa_store_order(struct xarray *xa, unsigned long index,
+		unsigned order, void *entry, gfp_t gfp)
+{
+	XA_STATE_ORDER(xas, xa, index, order);
+	void *curr;
+
+	do {
+		xas_lock(&xas);
+		curr = xas_store(&xas, entry);
+		xas_unlock(&xas);
+	} while (xas_nomem(&xas, gfp));
+
+	return curr;
+}
+
+static noinline void check_xa_err(struct xarray *xa)
+{
+	XA_BUG_ON(xa, xa_err(xa_store_index(xa, 0, GFP_NOWAIT)) != 0);
+	XA_BUG_ON(xa, xa_err(xa_erase(xa, 0)) != 0);
+#ifndef __KERNEL__
+	/* The kernel does not fail GFP_NOWAIT allocations */
+	XA_BUG_ON(xa, xa_err(xa_store_index(xa, 1, GFP_NOWAIT)) != -ENOMEM);
+	XA_BUG_ON(xa, xa_err(xa_store_index(xa, 1, GFP_NOWAIT)) != -ENOMEM);
+#endif
+	XA_BUG_ON(xa, xa_err(xa_store_index(xa, 1, GFP_KERNEL)) != 0);
+	XA_BUG_ON(xa, xa_err(xa_store(xa, 1, xa_mk_value(0), GFP_KERNEL)) != 0);
+	XA_BUG_ON(xa, xa_err(xa_erase(xa, 1)) != 0);
+// kills the test-suite :-(
+//	XA_BUG_ON(xa, xa_err(xa_store(xa, 0, xa_mk_internal(0), 0)) != -EINVAL);
+}
+
+static noinline void check_xas_retry(struct xarray *xa)
+{
+	XA_STATE(xas, xa, 0);
+	void *entry;
+
+	xa_store_index(xa, 0, GFP_KERNEL);
+	xa_store_index(xa, 1, GFP_KERNEL);
+
+	rcu_read_lock();
+	XA_BUG_ON(xa, xas_find(&xas, ULONG_MAX) != xa_mk_value(0));
+	xa_erase_index(xa, 1);
+	XA_BUG_ON(xa, !xa_is_retry(xas_reload(&xas)));
+	XA_BUG_ON(xa, xas_retry(&xas, NULL));
+	XA_BUG_ON(xa, xas_retry(&xas, xa_mk_value(0)));
+	xas_reset(&xas);
+	XA_BUG_ON(xa, xas.xa_node != XAS_RESTART);
+	XA_BUG_ON(xa, xas_next_entry(&xas, ULONG_MAX) != xa_mk_value(0));
+	XA_BUG_ON(xa, xas.xa_node != NULL);
+	rcu_read_unlock();
+
+	XA_BUG_ON(xa, xa_store_index(xa, 1, GFP_KERNEL) != NULL);
+
+	rcu_read_lock();
+	XA_BUG_ON(xa, !xa_is_internal(xas_reload(&xas)));
+	xas.xa_node = XAS_RESTART;
+	XA_BUG_ON(xa, xas_next_entry(&xas, ULONG_MAX) != xa_mk_value(0));
+	rcu_read_unlock();
+
+	/* Make sure we can iterate through retry entries */
+	xas_lock(&xas);
+	xas_set(&xas, 0);
+	xas_store(&xas, XA_RETRY_ENTRY);
+	xas_set(&xas, 1);
+	xas_store(&xas, XA_RETRY_ENTRY);
+
+	xas_set(&xas, 0);
+	xas_for_each(&xas, entry, ULONG_MAX) {
+		xas_store(&xas, xa_mk_index(xas.xa_index));
+	}
+	xas_unlock(&xas);
+
+	xa_erase_index(xa, 0);
+	xa_erase_index(xa, 1);
+}
+
+static noinline void check_xa_load(struct xarray *xa)
+{
+	unsigned long i, j;
+
+	for (i = 0; i < 1024; i++) {
+		for (j = 0; j < 1024; j++) {
+			void *entry = xa_load(xa, j);
+			if (j < i)
+				XA_BUG_ON(xa, xa_to_value(entry) != j);
+			else
+				XA_BUG_ON(xa, entry);
+		}
+		XA_BUG_ON(xa, xa_store_index(xa, i, GFP_KERNEL) != NULL);
+	}
+
+	for (i = 0; i < 1024; i++) {
+		for (j = 0; j < 1024; j++) {
+			void *entry = xa_load(xa, j);
+			if (j >= i)
+				XA_BUG_ON(xa, xa_to_value(entry) != j);
+			else
+				XA_BUG_ON(xa, entry);
+		}
+		xa_erase_index(xa, i);
+	}
+	XA_BUG_ON(xa, !xa_empty(xa));
+}
+
+static noinline void check_xa_mark_1(struct xarray *xa, unsigned long index)
+{
+	unsigned int order;
+	unsigned int max_order = IS_ENABLED(CONFIG_XARRAY_MULTI) ? 8 : 1;
+
+	/* NULL elements have no marks set */
+	XA_BUG_ON(xa, xa_get_mark(xa, index, XA_MARK_0));
+	xa_set_mark(xa, index, XA_MARK_0);
+	XA_BUG_ON(xa, xa_get_mark(xa, index, XA_MARK_0));
+
+	/* Storing a pointer will not make a mark appear */
+	XA_BUG_ON(xa, xa_store_index(xa, index, GFP_KERNEL) != NULL);
+	XA_BUG_ON(xa, xa_get_mark(xa, index, XA_MARK_0));
+	xa_set_mark(xa, index, XA_MARK_0);
+	XA_BUG_ON(xa, !xa_get_mark(xa, index, XA_MARK_0));
+
+	/* Setting one mark will not set another mark */
+	XA_BUG_ON(xa, xa_get_mark(xa, index + 1, XA_MARK_0));
+	XA_BUG_ON(xa, xa_get_mark(xa, index, XA_MARK_1));
+
+	/* Storing NULL clears marks, and they can't be set again */
+	xa_erase_index(xa, index);
+	XA_BUG_ON(xa, !xa_empty(xa));
+	XA_BUG_ON(xa, xa_get_mark(xa, index, XA_MARK_0));
+	xa_set_mark(xa, index, XA_MARK_0);
+	XA_BUG_ON(xa, xa_get_mark(xa, index, XA_MARK_0));
+
+	/*
+	 * Storing a multi-index entry over entries with marks gives the
+	 * entire entry the union of the marks
+	 */
+	BUG_ON((index % 4) != 0);
+	for (order = 2; order < max_order; order++) {
+		unsigned long base = round_down(index, 1UL << order);
+		unsigned long next = base + (1UL << order);
+		unsigned long i;
+
+		XA_BUG_ON(xa, xa_store_index(xa, index + 1, GFP_KERNEL));
+		xa_set_mark(xa, index + 1, XA_MARK_0);
+		XA_BUG_ON(xa, xa_store_index(xa, index + 2, GFP_KERNEL));
+		xa_set_mark(xa, index + 2, XA_MARK_2);
+		XA_BUG_ON(xa, xa_store_index(xa, next, GFP_KERNEL));
+		xa_store_order(xa, index, order, xa_mk_index(index),
+				GFP_KERNEL);
+		for (i = base; i < next; i++) {
+			XA_STATE(xas, xa, i);
+			unsigned int seen = 0;
+			void *entry;
+
+			XA_BUG_ON(xa, !xa_get_mark(xa, i, XA_MARK_0));
+			XA_BUG_ON(xa, xa_get_mark(xa, i, XA_MARK_1));
+			XA_BUG_ON(xa, !xa_get_mark(xa, i, XA_MARK_2));
+
+			/* We should see two elements in the array */
+			rcu_read_lock();
+			xas_for_each(&xas, entry, ULONG_MAX)
+				seen++;
+			rcu_read_unlock();
+			XA_BUG_ON(xa, seen != 2);
+
+			/* One of which is marked */
+			xas_set(&xas, 0);
+			seen = 0;
+			rcu_read_lock();
+			xas_for_each_marked(&xas, entry, ULONG_MAX, XA_MARK_0)
+				seen++;
+			rcu_read_unlock();
+			XA_BUG_ON(xa, seen != 1);
+		}
+		XA_BUG_ON(xa, xa_get_mark(xa, next, XA_MARK_0));
+		XA_BUG_ON(xa, xa_get_mark(xa, next, XA_MARK_1));
+		XA_BUG_ON(xa, xa_get_mark(xa, next, XA_MARK_2));
+		xa_erase_index(xa, index);
+		xa_erase_index(xa, next);
+		XA_BUG_ON(xa, !xa_empty(xa));
+	}
+	XA_BUG_ON(xa, !xa_empty(xa));
+}
+
+static noinline void check_xa_mark_2(struct xarray *xa)
+{
+	XA_STATE(xas, xa, 0);
+	unsigned long index;
+	unsigned int count = 0;
+	void *entry;
+
+	xa_store_index(xa, 0, GFP_KERNEL);
+	xa_set_mark(xa, 0, XA_MARK_0);
+	xas_lock(&xas);
+	xas_load(&xas);
+	xas_init_marks(&xas);
+	xas_unlock(&xas);
+	XA_BUG_ON(xa, !xa_get_mark(xa, 0, XA_MARK_0) == 0);
+
+	for (index = 3500; index < 4500; index++) {
+		xa_store_index(xa, index, GFP_KERNEL);
+		xa_set_mark(xa, index, XA_MARK_0);
+	}
+
+	xas_reset(&xas);
+	rcu_read_lock();
+	xas_for_each_marked(&xas, entry, ULONG_MAX, XA_MARK_0)
+		count++;
+	rcu_read_unlock();
+	XA_BUG_ON(xa, count != 1000);
+
+	xas_lock(&xas);
+	xas_for_each(&xas, entry, ULONG_MAX) {
+		xas_init_marks(&xas);
+		XA_BUG_ON(xa, !xa_get_mark(xa, xas.xa_index, XA_MARK_0));
+		XA_BUG_ON(xa, !xas_get_mark(&xas, XA_MARK_0));
+	}
+	xas_unlock(&xas);
+
+	xa_destroy(xa);
+}
+
+static noinline void check_xa_mark(struct xarray *xa)
+{
+	unsigned long index;
+
+	for (index = 0; index < 16384; index += 4)
+		check_xa_mark_1(xa, index);
+
+	check_xa_mark_2(xa);
+}
+
+static noinline void check_xa_shrink(struct xarray *xa)
+{
+	XA_STATE(xas, xa, 1);
+	struct xa_node *node;
+	unsigned int order;
+	unsigned int max_order = IS_ENABLED(CONFIG_XARRAY_MULTI) ? 15 : 1;
+
+	XA_BUG_ON(xa, !xa_empty(xa));
+	XA_BUG_ON(xa, xa_store_index(xa, 0, GFP_KERNEL) != NULL);
+	XA_BUG_ON(xa, xa_store_index(xa, 1, GFP_KERNEL) != NULL);
+
+	/*
+	 * Check that erasing the entry at 1 shrinks the tree and properly
+	 * marks the node as being deleted.
+	 */
+	xas_lock(&xas);
+	XA_BUG_ON(xa, xas_load(&xas) != xa_mk_value(1));
+	node = xas.xa_node;
+	XA_BUG_ON(xa, xa_entry_locked(xa, node, 0) != xa_mk_value(0));
+	XA_BUG_ON(xa, xas_store(&xas, NULL) != xa_mk_value(1));
+	XA_BUG_ON(xa, xa_load(xa, 1) != NULL);
+	XA_BUG_ON(xa, xas.xa_node != XAS_BOUNDS);
+	XA_BUG_ON(xa, xa_entry_locked(xa, node, 0) != XA_RETRY_ENTRY);
+	XA_BUG_ON(xa, xas_load(&xas) != NULL);
+	xas_unlock(&xas);
+	XA_BUG_ON(xa, xa_load(xa, 0) != xa_mk_value(0));
+	xa_erase_index(xa, 0);
+	XA_BUG_ON(xa, !xa_empty(xa));
+
+	for (order = 0; order < max_order; order++) {
+		unsigned long max = (1UL << order) - 1;
+		xa_store_order(xa, 0, order, xa_mk_value(0), GFP_KERNEL);
+		XA_BUG_ON(xa, xa_load(xa, max) != xa_mk_value(0));
+		XA_BUG_ON(xa, xa_load(xa, max + 1) != NULL);
+		rcu_read_lock();
+		node = xa_head(xa);
+		rcu_read_unlock();
+		XA_BUG_ON(xa, xa_store_index(xa, ULONG_MAX, GFP_KERNEL) !=
+				NULL);
+		rcu_read_lock();
+		XA_BUG_ON(xa, xa_head(xa) == node);
+		rcu_read_unlock();
+		XA_BUG_ON(xa, xa_load(xa, max + 1) != NULL);
+		xa_erase_index(xa, ULONG_MAX);
+		XA_BUG_ON(xa, xa->xa_head != node);
+		xa_erase_index(xa, 0);
+	}
+}
+
+static noinline void check_insert(struct xarray *xa)
+{
+	unsigned long i;
+
+	for (i = 0; i < 1024; i++) {
+		xa_insert_index(xa, i);
+		XA_BUG_ON(xa, xa_load(xa, i - 1) != NULL);
+		XA_BUG_ON(xa, xa_load(xa, i + 1) != NULL);
+		xa_erase_index(xa, i);
+	}
+
+	for (i = 10; i < BITS_PER_LONG; i++) {
+		xa_insert_index(xa, 1UL << i);
+		XA_BUG_ON(xa, xa_load(xa, (1UL << i) - 1) != NULL);
+		XA_BUG_ON(xa, xa_load(xa, (1UL << i) + 1) != NULL);
+		xa_erase_index(xa, 1UL << i);
+
+		xa_insert_index(xa, (1UL << i) - 1);
+		XA_BUG_ON(xa, xa_load(xa, (1UL << i) - 2) != NULL);
+		XA_BUG_ON(xa, xa_load(xa, 1UL << i) != NULL);
+		xa_erase_index(xa, (1UL << i) - 1);
+	}
+
+	xa_insert_index(xa, ~0UL);
+	XA_BUG_ON(xa, xa_load(xa, 0UL) != NULL);
+	XA_BUG_ON(xa, xa_load(xa, ~1UL) != NULL);
+	xa_erase_index(xa, ~0UL);
+
+	XA_BUG_ON(xa, !xa_empty(xa));
+}
+
+static noinline void check_cmpxchg(struct xarray *xa)
+{
+	void *FIVE = xa_mk_value(5);
+	void *SIX = xa_mk_value(6);
+	void *LOTS = xa_mk_value(12345678);
+
+	XA_BUG_ON(xa, !xa_empty(xa));
+	XA_BUG_ON(xa, xa_store_index(xa, 12345678, GFP_KERNEL) != NULL);
+	XA_BUG_ON(xa, xa_insert(xa, 12345678, xa, GFP_KERNEL) != -EBUSY);
+	XA_BUG_ON(xa, xa_cmpxchg(xa, 12345678, SIX, FIVE, GFP_KERNEL) != LOTS);
+	XA_BUG_ON(xa, xa_cmpxchg(xa, 12345678, LOTS, FIVE, GFP_KERNEL) != LOTS);
+	XA_BUG_ON(xa, xa_cmpxchg(xa, 12345678, FIVE, LOTS, GFP_KERNEL) != FIVE);
+	XA_BUG_ON(xa, xa_cmpxchg(xa, 5, FIVE, NULL, GFP_KERNEL) != NULL);
+	XA_BUG_ON(xa, xa_cmpxchg(xa, 5, NULL, FIVE, GFP_KERNEL) != NULL);
+	xa_erase_index(xa, 12345678);
+	xa_erase_index(xa, 5);
+	XA_BUG_ON(xa, !xa_empty(xa));
+}
+
+static noinline void check_reserve(struct xarray *xa)
+{
+	void *entry;
+	unsigned long index;
+	int count;
+
+	/* An array with a reserved entry is not empty */
+	XA_BUG_ON(xa, !xa_empty(xa));
+	XA_BUG_ON(xa, xa_reserve(xa, 12345678, GFP_KERNEL) != 0);
+	XA_BUG_ON(xa, xa_empty(xa));
+	XA_BUG_ON(xa, xa_load(xa, 12345678));
+	xa_release(xa, 12345678);
+	XA_BUG_ON(xa, !xa_empty(xa));
+
+	/* Releasing a used entry does nothing */
+	XA_BUG_ON(xa, xa_reserve(xa, 12345678, GFP_KERNEL) != 0);
+	XA_BUG_ON(xa, xa_store_index(xa, 12345678, GFP_NOWAIT) != NULL);
+	xa_release(xa, 12345678);
+	xa_erase_index(xa, 12345678);
+	XA_BUG_ON(xa, !xa_empty(xa));
+
+	/* cmpxchg sees a reserved entry as ZERO */
+	XA_BUG_ON(xa, xa_reserve(xa, 12345678, GFP_KERNEL) != 0);
+	XA_BUG_ON(xa, xa_cmpxchg(xa, 12345678, XA_ZERO_ENTRY,
+				xa_mk_value(12345678), GFP_NOWAIT) != NULL);
+	xa_release(xa, 12345678);
+	xa_erase_index(xa, 12345678);
+	XA_BUG_ON(xa, !xa_empty(xa));
+
+	/* xa_insert treats it as busy */
+	XA_BUG_ON(xa, xa_reserve(xa, 12345678, GFP_KERNEL) != 0);
+	XA_BUG_ON(xa, xa_insert(xa, 12345678, xa_mk_value(12345678), 0) !=
+			-EBUSY);
+	XA_BUG_ON(xa, xa_empty(xa));
+	XA_BUG_ON(xa, xa_erase(xa, 12345678) != NULL);
+	XA_BUG_ON(xa, !xa_empty(xa));
+
+	/* Can iterate through a reserved entry */
+	xa_store_index(xa, 5, GFP_KERNEL);
+	XA_BUG_ON(xa, xa_reserve(xa, 6, GFP_KERNEL) != 0);
+	xa_store_index(xa, 7, GFP_KERNEL);
+
+	count = 0;
+	xa_for_each(xa, index, entry) {
+		XA_BUG_ON(xa, index != 5 && index != 7);
+		count++;
+	}
+	XA_BUG_ON(xa, count != 2);
+
+	/* If we free a reserved entry, we should be able to allocate it */
+	if (xa->xa_flags & XA_FLAGS_ALLOC) {
+		u32 id;
+
+		XA_BUG_ON(xa, xa_alloc(xa, &id, xa_mk_value(8),
+					XA_LIMIT(5, 10), GFP_KERNEL) != 0);
+		XA_BUG_ON(xa, id != 8);
+
+		xa_release(xa, 6);
+		XA_BUG_ON(xa, xa_alloc(xa, &id, xa_mk_value(6),
+					XA_LIMIT(5, 10), GFP_KERNEL) != 0);
+		XA_BUG_ON(xa, id != 6);
+	}
+
+	xa_destroy(xa);
+}
+
+static noinline void check_xas_erase(struct xarray *xa)
+{
+	XA_STATE(xas, xa, 0);
+	void *entry;
+	unsigned long i, j;
+
+	for (i = 0; i < 200; i++) {
+		for (j = i; j < 2 * i + 17; j++) {
+			xas_set(&xas, j);
+			do {
+				xas_lock(&xas);
+				xas_store(&xas, xa_mk_index(j));
+				xas_unlock(&xas);
+			} while (xas_nomem(&xas, GFP_KERNEL));
+		}
+
+		xas_set(&xas, ULONG_MAX);
+		do {
+			xas_lock(&xas);
+			xas_store(&xas, xa_mk_value(0));
+			xas_unlock(&xas);
+		} while (xas_nomem(&xas, GFP_KERNEL));
+
+		xas_lock(&xas);
+		xas_store(&xas, NULL);
+
+		xas_set(&xas, 0);
+		j = i;
+		xas_for_each(&xas, entry, ULONG_MAX) {
+			XA_BUG_ON(xa, entry != xa_mk_index(j));
+			xas_store(&xas, NULL);
+			j++;
+		}
+		xas_unlock(&xas);
+		XA_BUG_ON(xa, !xa_empty(xa));
+	}
+}
+
+#ifdef CONFIG_XARRAY_MULTI
+static noinline void check_multi_store_1(struct xarray *xa, unsigned long index,
+		unsigned int order)
+{
+	XA_STATE(xas, xa, index);
+	unsigned long min = index & ~((1UL << order) - 1);
+	unsigned long max = min + (1UL << order);
+
+	xa_store_order(xa, index, order, xa_mk_index(index), GFP_KERNEL);
+	XA_BUG_ON(xa, xa_load(xa, min) != xa_mk_index(index));
+	XA_BUG_ON(xa, xa_load(xa, max - 1) != xa_mk_index(index));
+	XA_BUG_ON(xa, xa_load(xa, max) != NULL);
+	XA_BUG_ON(xa, xa_load(xa, min - 1) != NULL);
+
+	xas_lock(&xas);
+	XA_BUG_ON(xa, xas_store(&xas, xa_mk_index(min)) != xa_mk_index(index));
+	xas_unlock(&xas);
+	XA_BUG_ON(xa, xa_load(xa, min) != xa_mk_index(min));
+	XA_BUG_ON(xa, xa_load(xa, max - 1) != xa_mk_index(min));
+	XA_BUG_ON(xa, xa_load(xa, max) != NULL);
+	XA_BUG_ON(xa, xa_load(xa, min - 1) != NULL);
+
+	xa_erase_index(xa, min);
+	XA_BUG_ON(xa, !xa_empty(xa));
+}
+
+static noinline void check_multi_store_2(struct xarray *xa, unsigned long index,
+		unsigned int order)
+{
+	XA_STATE(xas, xa, index);
+	xa_store_order(xa, index, order, xa_mk_value(0), GFP_KERNEL);
+
+	xas_lock(&xas);
+	XA_BUG_ON(xa, xas_store(&xas, xa_mk_value(1)) != xa_mk_value(0));
+	XA_BUG_ON(xa, xas.xa_index != index);
+	XA_BUG_ON(xa, xas_store(&xas, NULL) != xa_mk_value(1));
+	xas_unlock(&xas);
+	XA_BUG_ON(xa, !xa_empty(xa));
+}
+
+static noinline void check_multi_store_3(struct xarray *xa, unsigned long index,
+		unsigned int order)
+{
+	XA_STATE(xas, xa, 0);
+	void *entry;
+	int n = 0;
+
+	xa_store_order(xa, index, order, xa_mk_index(index), GFP_KERNEL);
+
+	xas_lock(&xas);
+	xas_for_each(&xas, entry, ULONG_MAX) {
+		XA_BUG_ON(xa, entry != xa_mk_index(index));
+		n++;
+	}
+	XA_BUG_ON(xa, n != 1);
+	xas_set(&xas, index + 1);
+	xas_for_each(&xas, entry, ULONG_MAX) {
+		XA_BUG_ON(xa, entry != xa_mk_index(index));
+		n++;
+	}
+	XA_BUG_ON(xa, n != 2);
+	xas_unlock(&xas);
+
+	xa_destroy(xa);
+}
+#endif
+
+static noinline void check_multi_store(struct xarray *xa)
+{
+#ifdef CONFIG_XARRAY_MULTI
+	unsigned long i, j, k;
+	unsigned int max_order = (sizeof(long) == 4) ? 30 : 60;
+
+	/* Loading from any position returns the same value */
+	xa_store_order(xa, 0, 1, xa_mk_value(0), GFP_KERNEL);
+	XA_BUG_ON(xa, xa_load(xa, 0) != xa_mk_value(0));
+	XA_BUG_ON(xa, xa_load(xa, 1) != xa_mk_value(0));
+	XA_BUG_ON(xa, xa_load(xa, 2) != NULL);
+	rcu_read_lock();
+	XA_BUG_ON(xa, xa_to_node(xa_head(xa))->count != 2);
+	XA_BUG_ON(xa, xa_to_node(xa_head(xa))->nr_values != 2);
+	rcu_read_unlock();
+
+	/* Storing adjacent to the value does not alter the value */
+	xa_store(xa, 3, xa, GFP_KERNEL);
+	XA_BUG_ON(xa, xa_load(xa, 0) != xa_mk_value(0));
+	XA_BUG_ON(xa, xa_load(xa, 1) != xa_mk_value(0));
+	XA_BUG_ON(xa, xa_load(xa, 2) != NULL);
+	rcu_read_lock();
+	XA_BUG_ON(xa, xa_to_node(xa_head(xa))->count != 3);
+	XA_BUG_ON(xa, xa_to_node(xa_head(xa))->nr_values != 2);
+	rcu_read_unlock();
+
+	/* Overwriting multiple indexes works */
+	xa_store_order(xa, 0, 2, xa_mk_value(1), GFP_KERNEL);
+	XA_BUG_ON(xa, xa_load(xa, 0) != xa_mk_value(1));
+	XA_BUG_ON(xa, xa_load(xa, 1) != xa_mk_value(1));
+	XA_BUG_ON(xa, xa_load(xa, 2) != xa_mk_value(1));
+	XA_BUG_ON(xa, xa_load(xa, 3) != xa_mk_value(1));
+	XA_BUG_ON(xa, xa_load(xa, 4) != NULL);
+	rcu_read_lock();
+	XA_BUG_ON(xa, xa_to_node(xa_head(xa))->count != 4);
+	XA_BUG_ON(xa, xa_to_node(xa_head(xa))->nr_values != 4);
+	rcu_read_unlock();
+
+	/* We can erase multiple values with a single store */
+	xa_store_order(xa, 0, BITS_PER_LONG - 1, NULL, GFP_KERNEL);
+	XA_BUG_ON(xa, !xa_empty(xa));
+
+	/* Even when the first slot is empty but the others aren't */
+	xa_store_index(xa, 1, GFP_KERNEL);
+	xa_store_index(xa, 2, GFP_KERNEL);
+	xa_store_order(xa, 0, 2, NULL, GFP_KERNEL);
+	XA_BUG_ON(xa, !xa_empty(xa));
+
+	for (i = 0; i < max_order; i++) {
+		for (j = 0; j < max_order; j++) {
+			xa_store_order(xa, 0, i, xa_mk_index(i), GFP_KERNEL);
+			xa_store_order(xa, 0, j, xa_mk_index(j), GFP_KERNEL);
+
+			for (k = 0; k < max_order; k++) {
+				void *entry = xa_load(xa, (1UL << k) - 1);
+				if ((i < k) && (j < k))
+					XA_BUG_ON(xa, entry != NULL);
+				else
+					XA_BUG_ON(xa, entry != xa_mk_index(j));
+			}
+
+			xa_erase(xa, 0);
+			XA_BUG_ON(xa, !xa_empty(xa));
+		}
+	}
+
+	for (i = 0; i < 20; i++) {
+		check_multi_store_1(xa, 200, i);
+		check_multi_store_1(xa, 0, i);
+		check_multi_store_1(xa, (1UL << i) + 1, i);
+	}
+	check_multi_store_2(xa, 4095, 9);
+
+	for (i = 1; i < 20; i++) {
+		check_multi_store_3(xa, 0, i);
+		check_multi_store_3(xa, 1UL << i, i);
+	}
+#endif
+}
+
+static noinline void check_xa_alloc_1(struct xarray *xa, unsigned int base)
+{
+	int i;
+	u32 id;
+
+	XA_BUG_ON(xa, !xa_empty(xa));
+	/* An empty array should assign %base to the first alloc */
+	xa_alloc_index(xa, base, GFP_KERNEL);
+
+	/* Erasing it should make the array empty again */
+	xa_erase_index(xa, base);
+	XA_BUG_ON(xa, !xa_empty(xa));
+
+	/* And it should assign %base again */
+	xa_alloc_index(xa, base, GFP_KERNEL);
+
+	/* Allocating and then erasing a lot should not lose base */
+	for (i = base + 1; i < 2 * XA_CHUNK_SIZE; i++)
+		xa_alloc_index(xa, i, GFP_KERNEL);
+	for (i = base; i < 2 * XA_CHUNK_SIZE; i++)
+		xa_erase_index(xa, i);
+	xa_alloc_index(xa, base, GFP_KERNEL);
+
+	/* Destroying the array should do the same as erasing */
+	xa_destroy(xa);
+
+	/* And it should assign %base again */
+	xa_alloc_index(xa, base, GFP_KERNEL);
+
+	/* The next assigned ID should be base+1 */
+	xa_alloc_index(xa, base + 1, GFP_KERNEL);
+	xa_erase_index(xa, base + 1);
+
+	/* Storing a value should mark it used */
+	xa_store_index(xa, base + 1, GFP_KERNEL);
+	xa_alloc_index(xa, base + 2, GFP_KERNEL);
+
+	/* If we then erase base, it should be free */
+	xa_erase_index(xa, base);
+	xa_alloc_index(xa, base, GFP_KERNEL);
+
+	xa_erase_index(xa, base + 1);
+	xa_erase_index(xa, base + 2);
+
+	for (i = 1; i < 5000; i++) {
+		xa_alloc_index(xa, base + i, GFP_KERNEL);
+	}
+
+	xa_destroy(xa);
+
+	/* Check that we fail properly at the limit of allocation */
+	XA_BUG_ON(xa, xa_alloc(xa, &id, xa_mk_index(UINT_MAX - 1),
+				XA_LIMIT(UINT_MAX - 1, UINT_MAX),
+				GFP_KERNEL) != 0);
+	XA_BUG_ON(xa, id != 0xfffffffeU);
+	XA_BUG_ON(xa, xa_alloc(xa, &id, xa_mk_index(UINT_MAX),
+				XA_LIMIT(UINT_MAX - 1, UINT_MAX),
+				GFP_KERNEL) != 0);
+	XA_BUG_ON(xa, id != 0xffffffffU);
+	id = 3;
+	XA_BUG_ON(xa, xa_alloc(xa, &id, xa_mk_index(0),
+				XA_LIMIT(UINT_MAX - 1, UINT_MAX),
+				GFP_KERNEL) != -EBUSY);
+	XA_BUG_ON(xa, id != 3);
+	xa_destroy(xa);
+
+	XA_BUG_ON(xa, xa_alloc(xa, &id, xa_mk_index(10), XA_LIMIT(10, 5),
+				GFP_KERNEL) != -EBUSY);
+	XA_BUG_ON(xa, xa_store_index(xa, 3, GFP_KERNEL) != 0);
+	XA_BUG_ON(xa, xa_alloc(xa, &id, xa_mk_index(10), XA_LIMIT(10, 5),
+				GFP_KERNEL) != -EBUSY);
+	xa_erase_index(xa, 3);
+	XA_BUG_ON(xa, !xa_empty(xa));
+}
+
+static noinline void check_xa_alloc_2(struct xarray *xa, unsigned int base)
+{
+	unsigned int i, id;
+	unsigned long index;
+	void *entry;
+
+	/* Allocate and free a NULL and check xa_empty() behaves */
+	XA_BUG_ON(xa, !xa_empty(xa));
+	XA_BUG_ON(xa, xa_alloc(xa, &id, NULL, xa_limit_32b, GFP_KERNEL) != 0);
+	XA_BUG_ON(xa, id != base);
+	XA_BUG_ON(xa, xa_empty(xa));
+	XA_BUG_ON(xa, xa_erase(xa, id) != NULL);
+	XA_BUG_ON(xa, !xa_empty(xa));
+
+	/* Ditto, but check destroy instead of erase */
+	XA_BUG_ON(xa, !xa_empty(xa));
+	XA_BUG_ON(xa, xa_alloc(xa, &id, NULL, xa_limit_32b, GFP_KERNEL) != 0);
+	XA_BUG_ON(xa, id != base);
+	XA_BUG_ON(xa, xa_empty(xa));
+	xa_destroy(xa);
+	XA_BUG_ON(xa, !xa_empty(xa));
+
+	for (i = base; i < base + 10; i++) {
+		XA_BUG_ON(xa, xa_alloc(xa, &id, NULL, xa_limit_32b,
+					GFP_KERNEL) != 0);
+		XA_BUG_ON(xa, id != i);
+	}
+
+	XA_BUG_ON(xa, xa_store(xa, 3, xa_mk_index(3), GFP_KERNEL) != NULL);
+	XA_BUG_ON(xa, xa_store(xa, 4, xa_mk_index(4), GFP_KERNEL) != NULL);
+	XA_BUG_ON(xa, xa_store(xa, 4, NULL, GFP_KERNEL) != xa_mk_index(4));
+	XA_BUG_ON(xa, xa_erase(xa, 5) != NULL);
+	XA_BUG_ON(xa, xa_alloc(xa, &id, NULL, xa_limit_32b, GFP_KERNEL) != 0);
+	XA_BUG_ON(xa, id != 5);
+
+	xa_for_each(xa, index, entry) {
+		xa_erase_index(xa, index);
+	}
+
+	for (i = base; i < base + 9; i++) {
+		XA_BUG_ON(xa, xa_erase(xa, i) != NULL);
+		XA_BUG_ON(xa, xa_empty(xa));
+	}
+	XA_BUG_ON(xa, xa_erase(xa, 8) != NULL);
+	XA_BUG_ON(xa, xa_empty(xa));
+	XA_BUG_ON(xa, xa_erase(xa, base + 9) != NULL);
+	XA_BUG_ON(xa, !xa_empty(xa));
+
+	xa_destroy(xa);
+}
+
+static noinline void check_xa_alloc_3(struct xarray *xa, unsigned int base)
+{
+	struct xa_limit limit = XA_LIMIT(1, 0x3fff);
+	u32 next = 0;
+	unsigned int i, id;
+	unsigned long index;
+	void *entry;
+
+	XA_BUG_ON(xa, xa_alloc_cyclic(xa, &id, xa_mk_index(1), limit,
+				&next, GFP_KERNEL) != 0);
+	XA_BUG_ON(xa, id != 1);
+
+	next = 0x3ffd;
+	XA_BUG_ON(xa, xa_alloc_cyclic(xa, &id, xa_mk_index(0x3ffd), limit,
+				&next, GFP_KERNEL) != 0);
+	XA_BUG_ON(xa, id != 0x3ffd);
+	xa_erase_index(xa, 0x3ffd);
+	xa_erase_index(xa, 1);
+	XA_BUG_ON(xa, !xa_empty(xa));
+
+	for (i = 0x3ffe; i < 0x4003; i++) {
+		if (i < 0x4000)
+			entry = xa_mk_index(i);
+		else
+			entry = xa_mk_index(i - 0x3fff);
+		XA_BUG_ON(xa, xa_alloc_cyclic(xa, &id, entry, limit,
+					&next, GFP_KERNEL) != (id == 1));
+		XA_BUG_ON(xa, xa_mk_index(id) != entry);
+	}
+
+	/* Check wrap-around is handled correctly */
+	if (base != 0)
+		xa_erase_index(xa, base);
+	xa_erase_index(xa, base + 1);
+	next = UINT_MAX;
+	XA_BUG_ON(xa, xa_alloc_cyclic(xa, &id, xa_mk_index(UINT_MAX),
+				xa_limit_32b, &next, GFP_KERNEL) != 0);
+	XA_BUG_ON(xa, id != UINT_MAX);
+	XA_BUG_ON(xa, xa_alloc_cyclic(xa, &id, xa_mk_index(base),
+				xa_limit_32b, &next, GFP_KERNEL) != 1);
+	XA_BUG_ON(xa, id != base);
+	XA_BUG_ON(xa, xa_alloc_cyclic(xa, &id, xa_mk_index(base + 1),
+				xa_limit_32b, &next, GFP_KERNEL) != 0);
+	XA_BUG_ON(xa, id != base + 1);
+
+	xa_for_each(xa, index, entry)
+		xa_erase_index(xa, index);
+
+	XA_BUG_ON(xa, !xa_empty(xa));
+}
+
+static DEFINE_XARRAY_ALLOC(xa0);
+static DEFINE_XARRAY_ALLOC1(xa1);
+
+static noinline void check_xa_alloc(void)
+{
+	check_xa_alloc_1(&xa0, 0);
+	check_xa_alloc_1(&xa1, 1);
+	check_xa_alloc_2(&xa0, 0);
+	check_xa_alloc_2(&xa1, 1);
+	check_xa_alloc_3(&xa0, 0);
+	check_xa_alloc_3(&xa1, 1);
+}
+
+static noinline void __check_store_iter(struct xarray *xa, unsigned long start,
+			unsigned int order, unsigned int present)
+{
+	XA_STATE_ORDER(xas, xa, start, order);
+	void *entry;
+	unsigned int count = 0;
+
+retry:
+	xas_lock(&xas);
+	xas_for_each_conflict(&xas, entry) {
+		XA_BUG_ON(xa, !xa_is_value(entry));
+		XA_BUG_ON(xa, entry < xa_mk_index(start));
+		XA_BUG_ON(xa, entry > xa_mk_index(start + (1UL << order) - 1));
+		count++;
+	}
+	xas_store(&xas, xa_mk_index(start));
+	xas_unlock(&xas);
+	if (xas_nomem(&xas, GFP_KERNEL)) {
+		count = 0;
+		goto retry;
+	}
+	XA_BUG_ON(xa, xas_error(&xas));
+	XA_BUG_ON(xa, count != present);
+	XA_BUG_ON(xa, xa_load(xa, start) != xa_mk_index(start));
+	XA_BUG_ON(xa, xa_load(xa, start + (1UL << order) - 1) !=
+			xa_mk_index(start));
+	xa_erase_index(xa, start);
+}
+
+static noinline void check_store_iter(struct xarray *xa)
+{
+	unsigned int i, j;
+	unsigned int max_order = IS_ENABLED(CONFIG_XARRAY_MULTI) ? 20 : 1;
+
+	for (i = 0; i < max_order; i++) {
+		unsigned int min = 1 << i;
+		unsigned int max = (2 << i) - 1;
+		__check_store_iter(xa, 0, i, 0);
+		XA_BUG_ON(xa, !xa_empty(xa));
+		__check_store_iter(xa, min, i, 0);
+		XA_BUG_ON(xa, !xa_empty(xa));
+
+		xa_store_index(xa, min, GFP_KERNEL);
+		__check_store_iter(xa, min, i, 1);
+		XA_BUG_ON(xa, !xa_empty(xa));
+		xa_store_index(xa, max, GFP_KERNEL);
+		__check_store_iter(xa, min, i, 1);
+		XA_BUG_ON(xa, !xa_empty(xa));
+
+		for (j = 0; j < min; j++)
+			xa_store_index(xa, j, GFP_KERNEL);
+		__check_store_iter(xa, 0, i, min);
+		XA_BUG_ON(xa, !xa_empty(xa));
+		for (j = 0; j < min; j++)
+			xa_store_index(xa, min + j, GFP_KERNEL);
+		__check_store_iter(xa, min, i, min);
+		XA_BUG_ON(xa, !xa_empty(xa));
+	}
+#ifdef CONFIG_XARRAY_MULTI
+	xa_store_index(xa, 63, GFP_KERNEL);
+	xa_store_index(xa, 65, GFP_KERNEL);
+	__check_store_iter(xa, 64, 2, 1);
+	xa_erase_index(xa, 63);
+#endif
+	XA_BUG_ON(xa, !xa_empty(xa));
+}
+
+static noinline void check_multi_find(struct xarray *xa)
+{
+#ifdef CONFIG_XARRAY_MULTI
+	unsigned long index;
+
+	xa_store_order(xa, 12, 2, xa_mk_value(12), GFP_KERNEL);
+	XA_BUG_ON(xa, xa_store_index(xa, 16, GFP_KERNEL) != NULL);
+
+	index = 0;
+	XA_BUG_ON(xa, xa_find(xa, &index, ULONG_MAX, XA_PRESENT) !=
+			xa_mk_value(12));
+	XA_BUG_ON(xa, index != 12);
+	index = 13;
+	XA_BUG_ON(xa, xa_find(xa, &index, ULONG_MAX, XA_PRESENT) !=
+			xa_mk_value(12));
+	XA_BUG_ON(xa, (index < 12) || (index >= 16));
+	XA_BUG_ON(xa, xa_find_after(xa, &index, ULONG_MAX, XA_PRESENT) !=
+			xa_mk_value(16));
+	XA_BUG_ON(xa, index != 16);
+
+	xa_erase_index(xa, 12);
+	xa_erase_index(xa, 16);
+	XA_BUG_ON(xa, !xa_empty(xa));
+#endif
+}
+
+static noinline void check_multi_find_2(struct xarray *xa)
+{
+	unsigned int max_order = IS_ENABLED(CONFIG_XARRAY_MULTI) ? 10 : 1;
+	unsigned int i, j;
+	void *entry;
+
+	for (i = 0; i < max_order; i++) {
+		unsigned long index = 1UL << i;
+		for (j = 0; j < index; j++) {
+			XA_STATE(xas, xa, j + index);
+			xa_store_index(xa, index - 1, GFP_KERNEL);
+			xa_store_order(xa, index, i, xa_mk_index(index),
+					GFP_KERNEL);
+			rcu_read_lock();
+			xas_for_each(&xas, entry, ULONG_MAX) {
+				xa_erase_index(xa, index);
+			}
+			rcu_read_unlock();
+			xa_erase_index(xa, index - 1);
+			XA_BUG_ON(xa, !xa_empty(xa));
+		}
+	}
+}
+
+static noinline void check_find_1(struct xarray *xa)
+{
+	unsigned long i, j, k;
+
+	XA_BUG_ON(xa, !xa_empty(xa));
+
+	/*
+	 * Check xa_find with all pairs between 0 and 99 inclusive,
+	 * starting at every index between 0 and 99
+	 */
+	for (i = 0; i < 100; i++) {
+		XA_BUG_ON(xa, xa_store_index(xa, i, GFP_KERNEL) != NULL);
+		xa_set_mark(xa, i, XA_MARK_0);
+		for (j = 0; j < i; j++) {
+			XA_BUG_ON(xa, xa_store_index(xa, j, GFP_KERNEL) !=
+					NULL);
+			xa_set_mark(xa, j, XA_MARK_0);
+			for (k = 0; k < 100; k++) {
+				unsigned long index = k;
+				void *entry = xa_find(xa, &index, ULONG_MAX,
+								XA_PRESENT);
+				if (k <= j)
+					XA_BUG_ON(xa, index != j);
+				else if (k <= i)
+					XA_BUG_ON(xa, index != i);
+				else
+					XA_BUG_ON(xa, entry != NULL);
+
+				index = k;
+				entry = xa_find(xa, &index, ULONG_MAX,
+								XA_MARK_0);
+				if (k <= j)
+					XA_BUG_ON(xa, index != j);
+				else if (k <= i)
+					XA_BUG_ON(xa, index != i);
+				else
+					XA_BUG_ON(xa, entry != NULL);
+			}
+			xa_erase_index(xa, j);
+			XA_BUG_ON(xa, xa_get_mark(xa, j, XA_MARK_0));
+			XA_BUG_ON(xa, !xa_get_mark(xa, i, XA_MARK_0));
+		}
+		xa_erase_index(xa, i);
+		XA_BUG_ON(xa, xa_get_mark(xa, i, XA_MARK_0));
+	}
+	XA_BUG_ON(xa, !xa_empty(xa));
+}
+
+static noinline void check_find_2(struct xarray *xa)
+{
+	void *entry;
+	unsigned long i, j, index;
+
+	xa_for_each(xa, index, entry) {
+		XA_BUG_ON(xa, true);
+	}
+
+	for (i = 0; i < 1024; i++) {
+		xa_store_index(xa, index, GFP_KERNEL);
+		j = 0;
+		xa_for_each(xa, index, entry) {
+			XA_BUG_ON(xa, xa_mk_index(index) != entry);
+			XA_BUG_ON(xa, index != j++);
+		}
+	}
+
+	xa_destroy(xa);
+}
+
+static noinline void check_find_3(struct xarray *xa)
+{
+	XA_STATE(xas, xa, 0);
+	unsigned long i, j, k;
+	void *entry;
+
+	for (i = 0; i < 100; i++) {
+		for (j = 0; j < 100; j++) {
+			rcu_read_lock();
+			for (k = 0; k < 100; k++) {
+				xas_set(&xas, j);
+				xas_for_each_marked(&xas, entry, k, XA_MARK_0)
+					;
+				if (j > k)
+					XA_BUG_ON(xa,
+						xas.xa_node != XAS_RESTART);
+			}
+			rcu_read_unlock();
+		}
+		xa_store_index(xa, i, GFP_KERNEL);
+		xa_set_mark(xa, i, XA_MARK_0);
+	}
+	xa_destroy(xa);
+}
+
+static noinline void check_find(struct xarray *xa)
+{
+	check_find_1(xa);
+	check_find_2(xa);
+	check_find_3(xa);
+	check_multi_find(xa);
+	check_multi_find_2(xa);
+}
+
+/* See find_swap_entry() in mm/shmem.c */
+static noinline unsigned long xa_find_entry(struct xarray *xa, void *item)
+{
+	XA_STATE(xas, xa, 0);
+	unsigned int checked = 0;
+	void *entry;
+
+	rcu_read_lock();
+	xas_for_each(&xas, entry, ULONG_MAX) {
+		if (xas_retry(&xas, entry))
+			continue;
+		if (entry == item)
+			break;
+		checked++;
+		if ((checked % 4) != 0)
+			continue;
+		xas_pause(&xas);
+	}
+	rcu_read_unlock();
+
+	return entry ? xas.xa_index : -1;
+}
+
+static noinline void check_find_entry(struct xarray *xa)
+{
+#ifdef CONFIG_XARRAY_MULTI
+	unsigned int order;
+	unsigned long offset, index;
+
+	for (order = 0; order < 20; order++) {
+		for (offset = 0; offset < (1UL << (order + 3));
+		     offset += (1UL << order)) {
+			for (index = 0; index < (1UL << (order + 5));
+			     index += (1UL << order)) {
+				xa_store_order(xa, index, order,
+						xa_mk_index(index), GFP_KERNEL);
+				XA_BUG_ON(xa, xa_load(xa, index) !=
+						xa_mk_index(index));
+				XA_BUG_ON(xa, xa_find_entry(xa,
+						xa_mk_index(index)) != index);
+			}
+			XA_BUG_ON(xa, xa_find_entry(xa, xa) != -1);
+			xa_destroy(xa);
+		}
+	}
+#endif
+
+	XA_BUG_ON(xa, xa_find_entry(xa, xa) != -1);
+	xa_store_index(xa, ULONG_MAX, GFP_KERNEL);
+	XA_BUG_ON(xa, xa_find_entry(xa, xa) != -1);
+	XA_BUG_ON(xa, xa_find_entry(xa, xa_mk_index(ULONG_MAX)) != -1);
+	xa_erase_index(xa, ULONG_MAX);
+	XA_BUG_ON(xa, !xa_empty(xa));
+}
+
+static noinline void check_move_tiny(struct xarray *xa)
+{
+	XA_STATE(xas, xa, 0);
+
+	XA_BUG_ON(xa, !xa_empty(xa));
+	rcu_read_lock();
+	XA_BUG_ON(xa, xas_next(&xas) != NULL);
+	XA_BUG_ON(xa, xas_next(&xas) != NULL);
+	rcu_read_unlock();
+	xa_store_index(xa, 0, GFP_KERNEL);
+	rcu_read_lock();
+	xas_set(&xas, 0);
+	XA_BUG_ON(xa, xas_next(&xas) != xa_mk_index(0));
+	XA_BUG_ON(xa, xas_next(&xas) != NULL);
+	xas_set(&xas, 0);
+	XA_BUG_ON(xa, xas_prev(&xas) != xa_mk_index(0));
+	XA_BUG_ON(xa, xas_prev(&xas) != NULL);
+	rcu_read_unlock();
+	xa_erase_index(xa, 0);
+	XA_BUG_ON(xa, !xa_empty(xa));
+}
+
+static noinline void check_move_small(struct xarray *xa, unsigned long idx)
+{
+	XA_STATE(xas, xa, 0);
+	unsigned long i;
+
+	xa_store_index(xa, 0, GFP_KERNEL);
+	xa_store_index(xa, idx, GFP_KERNEL);
+
+	rcu_read_lock();
+	for (i = 0; i < idx * 4; i++) {
+		void *entry = xas_next(&xas);
+		if (i <= idx)
+			XA_BUG_ON(xa, xas.xa_node == XAS_RESTART);
+		XA_BUG_ON(xa, xas.xa_index != i);
+		if (i == 0 || i == idx)
+			XA_BUG_ON(xa, entry != xa_mk_index(i));
+		else
+			XA_BUG_ON(xa, entry != NULL);
+	}
+	xas_next(&xas);
+	XA_BUG_ON(xa, xas.xa_index != i);
+
+	do {
+		void *entry = xas_prev(&xas);
+		i--;
+		if (i <= idx)
+			XA_BUG_ON(xa, xas.xa_node == XAS_RESTART);
+		XA_BUG_ON(xa, xas.xa_index != i);
+		if (i == 0 || i == idx)
+			XA_BUG_ON(xa, entry != xa_mk_index(i));
+		else
+			XA_BUG_ON(xa, entry != NULL);
+	} while (i > 0);
+
+	xas_set(&xas, ULONG_MAX);
+	XA_BUG_ON(xa, xas_next(&xas) != NULL);
+	XA_BUG_ON(xa, xas.xa_index != ULONG_MAX);
+	XA_BUG_ON(xa, xas_next(&xas) != xa_mk_value(0));
+	XA_BUG_ON(xa, xas.xa_index != 0);
+	XA_BUG_ON(xa, xas_prev(&xas) != NULL);
+	XA_BUG_ON(xa, xas.xa_index != ULONG_MAX);
+	rcu_read_unlock();
+
+	xa_erase_index(xa, 0);
+	xa_erase_index(xa, idx);
+	XA_BUG_ON(xa, !xa_empty(xa));
+}
+
+static noinline void check_move(struct xarray *xa)
+{
+	XA_STATE(xas, xa, (1 << 16) - 1);
+	unsigned long i;
+
+	for (i = 0; i < (1 << 16); i++)
+		XA_BUG_ON(xa, xa_store_index(xa, i, GFP_KERNEL) != NULL);
+
+	rcu_read_lock();
+	do {
+		void *entry = xas_prev(&xas);
+		i--;
+		XA_BUG_ON(xa, entry != xa_mk_index(i));
+		XA_BUG_ON(xa, i != xas.xa_index);
+	} while (i != 0);
+
+	XA_BUG_ON(xa, xas_prev(&xas) != NULL);
+	XA_BUG_ON(xa, xas.xa_index != ULONG_MAX);
+
+	do {
+		void *entry = xas_next(&xas);
+		XA_BUG_ON(xa, entry != xa_mk_index(i));
+		XA_BUG_ON(xa, i != xas.xa_index);
+		i++;
+	} while (i < (1 << 16));
+	rcu_read_unlock();
+
+	for (i = (1 << 8); i < (1 << 15); i++)
+		xa_erase_index(xa, i);
+
+	i = xas.xa_index;
+
+	rcu_read_lock();
+	do {
+		void *entry = xas_prev(&xas);
+		i--;
+		if ((i < (1 << 8)) || (i >= (1 << 15)))
+			XA_BUG_ON(xa, entry != xa_mk_index(i));
+		else
+			XA_BUG_ON(xa, entry != NULL);
+		XA_BUG_ON(xa, i != xas.xa_index);
+	} while (i != 0);
+
+	XA_BUG_ON(xa, xas_prev(&xas) != NULL);
+	XA_BUG_ON(xa, xas.xa_index != ULONG_MAX);
+
+	do {
+		void *entry = xas_next(&xas);
+		if ((i < (1 << 8)) || (i >= (1 << 15)))
+			XA_BUG_ON(xa, entry != xa_mk_index(i));
+		else
+			XA_BUG_ON(xa, entry != NULL);
+		XA_BUG_ON(xa, i != xas.xa_index);
+		i++;
+	} while (i < (1 << 16));
+	rcu_read_unlock();
+
+	xa_destroy(xa);
+
+	check_move_tiny(xa);
+
+	for (i = 0; i < 16; i++)
+		check_move_small(xa, 1UL << i);
+
+	for (i = 2; i < 16; i++)
+		check_move_small(xa, (1UL << i) - 1);
+}
+
+static noinline void xa_store_many_order(struct xarray *xa,
+		unsigned long index, unsigned order)
+{
+	XA_STATE_ORDER(xas, xa, index, order);
+	unsigned int i = 0;
+
+	do {
+		xas_lock(&xas);
+		XA_BUG_ON(xa, xas_find_conflict(&xas));
+		xas_create_range(&xas);
+		if (xas_error(&xas))
+			goto unlock;
+		for (i = 0; i < (1U << order); i++) {
+			XA_BUG_ON(xa, xas_store(&xas, xa_mk_index(index + i)));
+			xas_next(&xas);
+		}
+unlock:
+		xas_unlock(&xas);
+	} while (xas_nomem(&xas, GFP_KERNEL));
+
+	XA_BUG_ON(xa, xas_error(&xas));
+}
+
+static noinline void check_create_range_1(struct xarray *xa,
+		unsigned long index, unsigned order)
+{
+	unsigned long i;
+
+	xa_store_many_order(xa, index, order);
+	for (i = index; i < index + (1UL << order); i++)
+		xa_erase_index(xa, i);
+	XA_BUG_ON(xa, !xa_empty(xa));
+}
+
+static noinline void check_create_range_2(struct xarray *xa, unsigned order)
+{
+	unsigned long i;
+	unsigned long nr = 1UL << order;
+
+	for (i = 0; i < nr * nr; i += nr)
+		xa_store_many_order(xa, i, order);
+	for (i = 0; i < nr * nr; i++)
+		xa_erase_index(xa, i);
+	XA_BUG_ON(xa, !xa_empty(xa));
+}
+
+static noinline void check_create_range_3(void)
+{
+	XA_STATE(xas, NULL, 0);
+	xas_set_err(&xas, -EEXIST);
+	xas_create_range(&xas);
+	XA_BUG_ON(NULL, xas_error(&xas) != -EEXIST);
+}
+
+static noinline void check_create_range_4(struct xarray *xa,
+		unsigned long index, unsigned order)
+{
+	XA_STATE_ORDER(xas, xa, index, order);
+	unsigned long base = xas.xa_index;
+	unsigned long i = 0;
+
+	xa_store_index(xa, index, GFP_KERNEL);
+	do {
+		xas_lock(&xas);
+		xas_create_range(&xas);
+		if (xas_error(&xas))
+			goto unlock;
+		for (i = 0; i < (1UL << order); i++) {
+			void *old = xas_store(&xas, xa_mk_index(base + i));
+			if (xas.xa_index == index)
+				XA_BUG_ON(xa, old != xa_mk_index(base + i));
+			else
+				XA_BUG_ON(xa, old != NULL);
+			xas_next(&xas);
+		}
+unlock:
+		xas_unlock(&xas);
+	} while (xas_nomem(&xas, GFP_KERNEL));
+
+	XA_BUG_ON(xa, xas_error(&xas));
+
+	for (i = base; i < base + (1UL << order); i++)
+		xa_erase_index(xa, i);
+	XA_BUG_ON(xa, !xa_empty(xa));
+}
+
+static noinline void check_create_range(struct xarray *xa)
+{
+	unsigned int order;
+	unsigned int max_order = IS_ENABLED(CONFIG_XARRAY_MULTI) ? 12 : 1;
+
+	for (order = 0; order < max_order; order++) {
+		check_create_range_1(xa, 0, order);
+		check_create_range_1(xa, 1U << order, order);
+		check_create_range_1(xa, 2U << order, order);
+		check_create_range_1(xa, 3U << order, order);
+		check_create_range_1(xa, 1U << 24, order);
+		if (order < 10)
+			check_create_range_2(xa, order);
+
+		check_create_range_4(xa, 0, order);
+		check_create_range_4(xa, 1U << order, order);
+		check_create_range_4(xa, 2U << order, order);
+		check_create_range_4(xa, 3U << order, order);
+		check_create_range_4(xa, 1U << 24, order);
+
+		check_create_range_4(xa, 1, order);
+		check_create_range_4(xa, (1U << order) + 1, order);
+		check_create_range_4(xa, (2U << order) + 1, order);
+		check_create_range_4(xa, (2U << order) - 1, order);
+		check_create_range_4(xa, (3U << order) + 1, order);
+		check_create_range_4(xa, (3U << order) - 1, order);
+		check_create_range_4(xa, (1U << 24) + 1, order);
+	}
+
+	check_create_range_3();
+}
+
+static noinline void __check_store_range(struct xarray *xa, unsigned long first,
+		unsigned long last)
+{
+#ifdef CONFIG_XARRAY_MULTI
+	xa_store_range(xa, first, last, xa_mk_index(first), GFP_KERNEL);
+
+	XA_BUG_ON(xa, xa_load(xa, first) != xa_mk_index(first));
+	XA_BUG_ON(xa, xa_load(xa, last) != xa_mk_index(first));
+	XA_BUG_ON(xa, xa_load(xa, first - 1) != NULL);
+	XA_BUG_ON(xa, xa_load(xa, last + 1) != NULL);
+
+	xa_store_range(xa, first, last, NULL, GFP_KERNEL);
+#endif
+
+	XA_BUG_ON(xa, !xa_empty(xa));
+}
+
+static noinline void check_store_range(struct xarray *xa)
+{
+	unsigned long i, j;
+
+	for (i = 0; i < 128; i++) {
+		for (j = i; j < 128; j++) {
+			__check_store_range(xa, i, j);
+			__check_store_range(xa, 128 + i, 128 + j);
+			__check_store_range(xa, 4095 + i, 4095 + j);
+			__check_store_range(xa, 4096 + i, 4096 + j);
+			__check_store_range(xa, 123456 + i, 123456 + j);
+			__check_store_range(xa, (1 << 24) + i, (1 << 24) + j);
+		}
+	}
+}
+
+static void check_align_1(struct xarray *xa, char *name)
+{
+	int i;
+	unsigned int id;
+	unsigned long index;
+	void *entry;
+
+	for (i = 0; i < 8; i++) {
+		XA_BUG_ON(xa, xa_alloc(xa, &id, name + i, xa_limit_32b,
+					GFP_KERNEL) != 0);
+		XA_BUG_ON(xa, id != i);
+	}
+	xa_for_each(xa, index, entry)
+		XA_BUG_ON(xa, xa_is_err(entry));
+	xa_destroy(xa);
+}
+
+/*
+ * We should always be able to store without allocating memory after
+ * reserving a slot.
+ */
+static void check_align_2(struct xarray *xa, char *name)
+{
+	int i;
+
+	XA_BUG_ON(xa, !xa_empty(xa));
+
+	for (i = 0; i < 8; i++) {
+		XA_BUG_ON(xa, xa_store(xa, 0, name + i, GFP_KERNEL) != NULL);
+		xa_erase(xa, 0);
+	}
+
+	for (i = 0; i < 8; i++) {
+		XA_BUG_ON(xa, xa_reserve(xa, 0, GFP_KERNEL) != 0);
+		XA_BUG_ON(xa, xa_store(xa, 0, name + i, 0) != NULL);
+		xa_erase(xa, 0);
+	}
+
+	XA_BUG_ON(xa, !xa_empty(xa));
+}
+
+static noinline void check_align(struct xarray *xa)
+{
+	char name[] = "Motorola 68000";
+
+	check_align_1(xa, name);
+	check_align_1(xa, name + 1);
+	check_align_1(xa, name + 2);
+	check_align_1(xa, name + 3);
+	check_align_2(xa, name);
+}
+
+static LIST_HEAD(shadow_nodes);
+
+static void test_update_node(struct xa_node *node)
+{
+	if (node->count && node->count == node->nr_values) {
+		if (list_empty(&node->private_list))
+			list_add(&shadow_nodes, &node->private_list);
+	} else {
+		if (!list_empty(&node->private_list))
+			list_del_init(&node->private_list);
+	}
+}
+
+static noinline void shadow_remove(struct xarray *xa)
+{
+	struct xa_node *node;
+
+	xa_lock(xa);
+	while ((node = list_first_entry_or_null(&shadow_nodes,
+					struct xa_node, private_list))) {
+		XA_STATE(xas, node->array, 0);
+		XA_BUG_ON(xa, node->array != xa);
+		list_del_init(&node->private_list);
+		xas.xa_node = xa_parent_locked(node->array, node);
+		xas.xa_offset = node->offset;
+		xas.xa_shift = node->shift + XA_CHUNK_SHIFT;
+		xas_set_update(&xas, test_update_node);
+		xas_store(&xas, NULL);
+	}
+	xa_unlock(xa);
+}
+
+static noinline void check_workingset(struct xarray *xa, unsigned long index)
+{
+	XA_STATE(xas, xa, index);
+	xas_set_update(&xas, test_update_node);
+
+	do {
+		xas_lock(&xas);
+		xas_store(&xas, xa_mk_value(0));
+		xas_next(&xas);
+		xas_store(&xas, xa_mk_value(1));
+		xas_unlock(&xas);
+	} while (xas_nomem(&xas, GFP_KERNEL));
+
+	XA_BUG_ON(xa, list_empty(&shadow_nodes));
+
+	xas_lock(&xas);
+	xas_next(&xas);
+	xas_store(&xas, &xas);
+	XA_BUG_ON(xa, !list_empty(&shadow_nodes));
+
+	xas_store(&xas, xa_mk_value(2));
+	xas_unlock(&xas);
+	XA_BUG_ON(xa, list_empty(&shadow_nodes));
+
+	shadow_remove(xa);
+	XA_BUG_ON(xa, !list_empty(&shadow_nodes));
+	XA_BUG_ON(xa, !xa_empty(xa));
+}
+
+/*
+ * Check that the pointer / value / sibling entries are accounted the
+ * way we expect them to be.
+ */
+static noinline void check_account(struct xarray *xa)
+{
+#ifdef CONFIG_XARRAY_MULTI
+	unsigned int order;
+
+	for (order = 1; order < 12; order++) {
+		XA_STATE(xas, xa, 1 << order);
+
+		xa_store_order(xa, 0, order, xa, GFP_KERNEL);
+		rcu_read_lock();
+		xas_load(&xas);
+		XA_BUG_ON(xa, xas.xa_node->count == 0);
+		XA_BUG_ON(xa, xas.xa_node->count > (1 << order));
+		XA_BUG_ON(xa, xas.xa_node->nr_values != 0);
+		rcu_read_unlock();
+
+		xa_store_order(xa, 1 << order, order, xa_mk_index(1UL << order),
+				GFP_KERNEL);
+		XA_BUG_ON(xa, xas.xa_node->count != xas.xa_node->nr_values * 2);
+
+		xa_erase(xa, 1 << order);
+		XA_BUG_ON(xa, xas.xa_node->nr_values != 0);
+
+		xa_erase(xa, 0);
+		XA_BUG_ON(xa, !xa_empty(xa));
+	}
+#endif
+}
+
+static noinline void check_destroy(struct xarray *xa)
+{
+	unsigned long index;
+
+	XA_BUG_ON(xa, !xa_empty(xa));
+
+	/* Destroying an empty array is a no-op */
+	xa_destroy(xa);
+	XA_BUG_ON(xa, !xa_empty(xa));
+
+	/* Destroying an array with a single entry */
+	for (index = 0; index < 1000; index++) {
+		xa_store_index(xa, index, GFP_KERNEL);
+		XA_BUG_ON(xa, xa_empty(xa));
+		xa_destroy(xa);
+		XA_BUG_ON(xa, !xa_empty(xa));
+	}
+
+	/* Destroying an array with a single entry at ULONG_MAX */
+	xa_store(xa, ULONG_MAX, xa, GFP_KERNEL);
+	XA_BUG_ON(xa, xa_empty(xa));
+	xa_destroy(xa);
+	XA_BUG_ON(xa, !xa_empty(xa));
+
+#ifdef CONFIG_XARRAY_MULTI
+	/* Destroying an array with a multi-index entry */
+	xa_store_order(xa, 1 << 11, 11, xa, GFP_KERNEL);
+	XA_BUG_ON(xa, xa_empty(xa));
+	xa_destroy(xa);
+	XA_BUG_ON(xa, !xa_empty(xa));
+#endif
+}
+
+static DEFINE_XARRAY(array);
+
+static int xarray_checks(void)
+{
+	check_xa_err(&array);
+	check_xas_retry(&array);
+	check_xa_load(&array);
+	check_xa_mark(&array);
+	check_xa_shrink(&array);
+	check_xas_erase(&array);
+	check_insert(&array);
+	check_cmpxchg(&array);
+	check_reserve(&array);
+	check_reserve(&xa0);
+	check_multi_store(&array);
+	check_xa_alloc();
+	check_find(&array);
+	check_find_entry(&array);
+	check_account(&array);
+	check_destroy(&array);
+	check_move(&array);
+	check_create_range(&array);
+	check_store_range(&array);
+	check_store_iter(&array);
+	check_align(&xa0);
+
+	check_workingset(&array, 0);
+	check_workingset(&array, 64);
+	check_workingset(&array, 4096);
+
+	printk("XArray: %u of %u tests passed\n", tests_passed, tests_run);
+	return (tests_run == tests_passed) ? 0 : -EINVAL;
+}
+
+static void xarray_exit(void)
+{
+}
+
+module_init(xarray_checks);
+module_exit(xarray_exit);
+MODULE_AUTHOR("Matthew Wilcox <willy@infradead.org>");
+MODULE_LICENSE("GPL");