lib/test_maple_tree: add testing for maple tree

This is a test suite that uses the radix test infrastructure.  It has been
split into its own commit to allow for easier review of the maple tree
code.

The testing includes:
- Allocation of nodes
- gfp flag allocation checks
- Expansion & contraction of tree
- preallocation checks
- tree navigation by next/prev
- tree navigation by iterators (mas_for_each, etc)
- Number of nodes for a given number of entries
- Generic tree construction tests
- Addition and removal of entries in forward and reverse numerical indexes
- gap searching both forward and reverse
- Combining gaps by overwriting entries in different ways
- splitting right-most node
- splitting left-most node
- overwriting multiple slots
- overwriting across different levels of the tree
- overwriting the middle of a tree
- causing a 3-way split up to the root by overwriting the last slot and
  first slot of different nodes and spanning different levels
- RCU stress testing of the tree with threads
- Duplication of the tree by entry count
- Tests which were generated by fuzzers have been added.
- A large number of tests which come from recording crashing in a VM and
  reconstructing the tree (see check_erase2_set())

Link: https://lkml.kernel.org/r/20220906194824.2110408-8-Liam.Howlett@oracle.com
Signed-off-by: Liam R. Howlett <Liam.Howlett@oracle.com>
Tested-by: Yu Zhao <yuzhao@google.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: David Howells <dhowells@redhat.com>
Cc: Davidlohr Bueso <dave@stgolabs.net>
Cc: "Matthew Wilcox (Oracle)" <willy@infradead.org>
Cc: SeongJae Park <sj@kernel.org>
Cc: Sven Schnelle <svens@linux.ibm.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Will Deacon <will@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

2 files changed, 38314 insertions, 2 deletions

diff --git a/lib/test_maple_tree.c b/lib/test_maple_tree.c
new file mode 100644
index 000000000000..4f69e009a015
--- /dev/null
+++ b/lib/test_maple_tree.c
@@ -0,0 +1,38307 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * test_maple_tree.c: Test the maple tree API
+ * Copyright (c) 2018 Liam R. Howlett
+ * Author: Liam R. Howlett <Liam.Howlett@Oracle.com>
+ */
+
+#include <linux/maple_tree.h>
+#include <linux/module.h>
+#include <stdlib.h>
+#include <time.h>
+
+#define MTREE_ALLOC_MAX 0x2000000000000Ul
+#define CONFIG_DEBUG_MAPLE_TREE
+#define CONFIG_MAPLE_SEARCH
+/* #define BENCH_SLOT_STORE */
+/* #define BENCH_NODE_STORE */
+/* #define BENCH_AWALK */
+/* #define BENCH_WALK */
+/* #define BENCH_MT_FOR_EACH */
+/* #define BENCH_FORK */
+static
+int mtree_insert_index(struct maple_tree *mt, unsigned long index, gfp_t gfp)
+{
+	return mtree_insert(mt, index, xa_mk_value(index & LONG_MAX), gfp);
+}
+
+static void mtree_erase_index(struct maple_tree *mt, unsigned long index)
+{
+	MT_BUG_ON(mt, mtree_erase(mt, index) != xa_mk_value(index & LONG_MAX));
+	MT_BUG_ON(mt, mtree_load(mt, index) != NULL);
+}
+
+static int mtree_test_insert(struct maple_tree *mt, unsigned long index,
+				void *ptr)
+{
+	return mtree_insert(mt, index, ptr, GFP_KERNEL);
+}
+
+static int mtree_test_store_range(struct maple_tree *mt, unsigned long start,
+				unsigned long end, void *ptr)
+{
+	return mtree_store_range(mt, start, end, ptr, GFP_KERNEL);
+}
+
+static int mtree_test_store(struct maple_tree *mt, unsigned long start,
+				void *ptr)
+{
+	return mtree_test_store_range(mt, start, start, ptr);
+}
+
+static int mtree_test_insert_range(struct maple_tree *mt, unsigned long start,
+				unsigned long end, void *ptr)
+{
+	return mtree_insert_range(mt, start, end, ptr, GFP_KERNEL);
+}
+
+static void *mtree_test_load(struct maple_tree *mt, unsigned long index)
+{
+	return mtree_load(mt, index);
+}
+
+static void *mtree_test_erase(struct maple_tree *mt, unsigned long index)
+{
+	return mtree_erase(mt, index);
+}
+
+static noinline void check_mtree_alloc_range(struct maple_tree *mt,
+		unsigned long start, unsigned long end, unsigned long size,
+		unsigned long expected, int eret, void *ptr)
+{
+
+	unsigned long result = expected + 1;
+	int ret;
+
+	ret = mtree_alloc_range(mt, &result, ptr, size, start, end,
+			GFP_KERNEL);
+	MT_BUG_ON(mt, ret != eret);
+	if (ret)
+		return;
+
+	MT_BUG_ON(mt, result != expected);
+}
+
+static noinline void check_mtree_alloc_rrange(struct maple_tree *mt,
+		unsigned long start, unsigned long end, unsigned long size,
+		unsigned long expected, int eret, void *ptr)
+{
+
+	unsigned long result = expected + 1;
+	int ret;
+
+	ret = mtree_alloc_rrange(mt, &result, ptr, size, start, end - 1,
+			GFP_KERNEL);
+	MT_BUG_ON(mt, ret != eret);
+	if (ret)
+		return;
+
+	MT_BUG_ON(mt, result != expected);
+}
+
+static noinline void check_load(struct maple_tree *mt, unsigned long index,
+				void *ptr)
+{
+	void *ret = mtree_test_load(mt, index);
+
+	if (ret != ptr)
+		pr_err("Load %lu returned %p expect %p\n", index, ret, ptr);
+	MT_BUG_ON(mt, ret != ptr);
+}
+
+static noinline void check_store_range(struct maple_tree *mt,
+		unsigned long start, unsigned long end, void *ptr, int expected)
+{
+	int ret = -EINVAL;
+	unsigned long i;
+
+	ret = mtree_test_store_range(mt, start, end, ptr);
+	MT_BUG_ON(mt, ret != expected);
+
+	if (ret)
+		return;
+
+	for (i = start; i <= end; i++)
+		check_load(mt, i, ptr);
+}
+
+static noinline void check_insert_range(struct maple_tree *mt,
+		unsigned long start, unsigned long end, void *ptr, int expected)
+{
+	int ret = -EINVAL;
+	unsigned long i;
+
+	ret = mtree_test_insert_range(mt, start, end, ptr);
+	MT_BUG_ON(mt, ret != expected);
+
+	if (ret)
+		return;
+
+	for (i = start; i <= end; i++)
+		check_load(mt, i, ptr);
+}
+
+static noinline void check_insert(struct maple_tree *mt, unsigned long index,
+		void *ptr)
+{
+	int ret = -EINVAL;
+
+	ret = mtree_test_insert(mt, index, ptr);
+	MT_BUG_ON(mt, ret != 0);
+}
+
+static noinline void check_erase(struct maple_tree *mt, unsigned long index,
+		void *ptr)
+{
+	MT_BUG_ON(mt, mtree_test_erase(mt, index) != ptr);
+}
+
+static noinline void check_dup_insert(struct maple_tree *mt,
+				      unsigned long index, void *ptr)
+{
+	int ret = -EINVAL;
+
+	ret = mtree_test_insert(mt, index, ptr);
+	MT_BUG_ON(mt, ret != -EEXIST);
+}
+
+
+static noinline
+void check_index_load(struct maple_tree *mt, unsigned long index)
+{
+	return check_load(mt, index, xa_mk_value(index & LONG_MAX));
+}
+
+static noinline void check_nomem(struct maple_tree *mt)
+{
+	MA_STATE(ms, mt, 1, 1);
+
+	MT_BUG_ON(mt, !mtree_empty(mt));
+	/* Ensure no bypassing of allocation failures */
+	mt_set_non_kernel(0);
+
+	/* Storing something at 1 requires memory allocation */
+	MT_BUG_ON(mt, mtree_insert(mt, 1, &ms, GFP_ATOMIC) != -ENOMEM);
+	/* Storing something at 0 does not */
+	MT_BUG_ON(mt, mtree_insert(mt, 0, &ms, GFP_ATOMIC) != 0);
+
+	/*
+	 * Simulate two threads racing; the first one fails to allocate
+	 * memory to insert an entry at 1, then the second one succeeds
+	 * in allocating memory to insert an entry at 2.  The first one
+	 * then needs to free the node it allocated.  LeakSanitizer will
+	 * notice this, as will the 'nr_allocated' debugging aid in the
+	 * userspace test suite.
+	 */
+	mtree_lock(mt);
+	mas_store(&ms, &ms); /* insert 1 -> &ms, fails. */
+	MT_BUG_ON(mt, ms.node != MA_ERROR(-ENOMEM));
+	mas_nomem(&ms, GFP_KERNEL); /* Node allocated in here. */
+	MT_BUG_ON(mt, ms.node != MAS_START);
+	mtree_unlock(mt);
+	MT_BUG_ON(mt, mtree_insert(mt, 2, mt, GFP_KERNEL) != 0);
+	mtree_lock(mt);
+	mas_store(&ms, &ms); /* insert 1 -> &ms */
+	mas_nomem(&ms, GFP_KERNEL); /* Node allocated in here. */
+	mtree_unlock(mt);
+	mtree_destroy(mt);
+}
+
+static inline int not_empty(struct maple_node *node)
+{
+	int i;
+
+	if (node->parent)
+		return 1;
+
+	for (i = 0; i < ARRAY_SIZE(node->slot); i++)
+		if (node->slot[i])
+			return 1;
+
+	return 0;
+}
+
+static noinline void check_new_node(struct maple_tree *mt)
+{
+
+	struct maple_node *mn, *mn2, *mn3;
+	struct maple_alloc *smn;
+	struct maple_node *nodes[100];
+	int i, j, total;
+
+	MA_STATE(mas, mt, 0, 0);
+
+	/* Try allocating 3 nodes */
+	mtree_lock(mt);
+	/* request 3 nodes to be allocated. */
+	mas_node_count(&mas, 3);
+	/* Allocation request of 3. */
+	MT_BUG_ON(mt, mas_alloc_req(&mas) != 3);
+	/* Allocate failed. */
+	MT_BUG_ON(mt, mas.node != MA_ERROR(-ENOMEM));
+	MT_BUG_ON(mt, !mas_nomem(&mas, GFP_KERNEL));
+
+	MT_BUG_ON(mt, mas_allocated(&mas) != 3);
+	mn = mas_pop_node(&mas);
+	MT_BUG_ON(mt, not_empty(mn));
+	MT_BUG_ON(mt, mn == NULL);
+	MT_BUG_ON(mt, mas.alloc == NULL);
+	MT_BUG_ON(mt, mas.alloc->slot[0] == NULL);
+	mas_push_node(&mas, mn);
+	mas_nomem(&mas, GFP_KERNEL); /* free */
+	mtree_unlock(mt);
+
+
+	/* Try allocating 1 node, then 2 more */
+	mtree_lock(mt);
+	/* Set allocation request to 1. */
+	mas_set_alloc_req(&mas, 1);
+	/* Check Allocation request of 1. */
+	MT_BUG_ON(mt, mas_alloc_req(&mas) != 1);
+	mas_set_err(&mas, -ENOMEM);
+	/* Validate allocation request. */
+	MT_BUG_ON(mt, !mas_nomem(&mas, GFP_KERNEL));
+	/* Eat the requested node. */
+	mn = mas_pop_node(&mas);
+	MT_BUG_ON(mt, not_empty(mn));
+	MT_BUG_ON(mt, mn == NULL);
+	MT_BUG_ON(mt, mn->slot[0] != NULL);
+	MT_BUG_ON(mt, mn->slot[1] != NULL);
+	MT_BUG_ON(mt, mas_allocated(&mas) != 0);
+
+	ma_free_rcu(mn);
+	mas.node = MAS_START;
+	mas_nomem(&mas, GFP_KERNEL);
+	/* Allocate 3 nodes, will fail. */
+	mas_node_count(&mas, 3);
+	/* Drop the lock and allocate 3 nodes. */
+	mas_nomem(&mas, GFP_KERNEL);
+	/* Ensure 3 are allocated. */
+	MT_BUG_ON(mt, mas_allocated(&mas) != 3);
+	/* Allocation request of 0. */
+	MT_BUG_ON(mt, mas_alloc_req(&mas) != 0);
+
+	MT_BUG_ON(mt, mas.alloc == NULL);
+	MT_BUG_ON(mt, mas.alloc->slot[0] == NULL);
+	MT_BUG_ON(mt, mas.alloc->slot[1] == NULL);
+	/* Ensure we counted 3. */
+	MT_BUG_ON(mt, mas_allocated(&mas) != 3);
+	/* Free. */
+	mas_nomem(&mas, GFP_KERNEL);
+
+	/* Set allocation request to 1. */
+	mas_set_alloc_req(&mas, 1);
+	MT_BUG_ON(mt, mas_alloc_req(&mas) != 1);
+	mas_set_err(&mas, -ENOMEM);
+	/* Validate allocation request. */
+	MT_BUG_ON(mt, !mas_nomem(&mas, GFP_KERNEL));
+	MT_BUG_ON(mt, mas_allocated(&mas) != 1);
+	/* Check the node is only one node. */
+	mn = mas_pop_node(&mas);
+	MT_BUG_ON(mt, not_empty(mn));
+	MT_BUG_ON(mt, mas_allocated(&mas) != 0);
+	MT_BUG_ON(mt, mn == NULL);
+	MT_BUG_ON(mt, mn->slot[0] != NULL);
+	MT_BUG_ON(mt, mn->slot[1] != NULL);
+	MT_BUG_ON(mt, mas_allocated(&mas) != 0);
+	mas_push_node(&mas, mn);
+	MT_BUG_ON(mt, mas_allocated(&mas) != 1);
+	MT_BUG_ON(mt, mas.alloc->node_count);
+
+	mas_set_alloc_req(&mas, 2); /* request 2 more. */
+	MT_BUG_ON(mt, mas_alloc_req(&mas) != 2);
+	mas_set_err(&mas, -ENOMEM);
+	MT_BUG_ON(mt, !mas_nomem(&mas, GFP_KERNEL));
+	MT_BUG_ON(mt, mas_allocated(&mas) != 3);
+	MT_BUG_ON(mt, mas.alloc == NULL);
+	MT_BUG_ON(mt, mas.alloc->slot[0] == NULL);
+	MT_BUG_ON(mt, mas.alloc->slot[1] == NULL);
+	for (i = 2; i >= 0; i--) {
+		mn = mas_pop_node(&mas);
+		MT_BUG_ON(mt, mas_allocated(&mas) != i);
+		MT_BUG_ON(mt, !mn);
+		MT_BUG_ON(mt, not_empty(mn));
+		ma_free_rcu(mn);
+	}
+
+	total = 64;
+	mas_set_alloc_req(&mas, total); /* request 2 more. */
+	MT_BUG_ON(mt, mas_alloc_req(&mas) != total);
+	mas_set_err(&mas, -ENOMEM);
+	MT_BUG_ON(mt, !mas_nomem(&mas, GFP_KERNEL));
+	for (i = total; i > 0; i--) {
+		unsigned int e = 0; /* expected node_count */
+
+		if (i >= 35)
+			e = i - 35;
+		else if (i >= 5)
+			e = i - 5;
+		else if (i >= 2)
+			e = i - 2;
+		MT_BUG_ON(mt, mas.alloc->node_count != e);
+		mn = mas_pop_node(&mas);
+		MT_BUG_ON(mt, not_empty(mn));
+		MT_BUG_ON(mt, mas_allocated(&mas) != i - 1);
+		MT_BUG_ON(mt, !mn);
+		ma_free_rcu(mn);
+	}
+
+	total = 100;
+	for (i = 1; i < total; i++) {
+		mas_set_alloc_req(&mas, i);
+		mas_set_err(&mas, -ENOMEM);
+		MT_BUG_ON(mt, !mas_nomem(&mas, GFP_KERNEL));
+		for (j = i; j > 0; j--) {
+			mn = mas_pop_node(&mas);
+			MT_BUG_ON(mt, mas_allocated(&mas) != j - 1);
+			MT_BUG_ON(mt, !mn);
+			MT_BUG_ON(mt, not_empty(mn));
+			mas_push_node(&mas, mn);
+			MT_BUG_ON(mt, mas_allocated(&mas) != j);
+			mn = mas_pop_node(&mas);
+			MT_BUG_ON(mt, not_empty(mn));
+			MT_BUG_ON(mt, mas_allocated(&mas) != j - 1);
+			ma_free_rcu(mn);
+		}
+		MT_BUG_ON(mt, mas_allocated(&mas) != 0);
+
+		mas_set_alloc_req(&mas, i);
+		mas_set_err(&mas, -ENOMEM);
+		MT_BUG_ON(mt, !mas_nomem(&mas, GFP_KERNEL));
+		for (j = 0; j <= i/2; j++) {
+			MT_BUG_ON(mt, mas_allocated(&mas) != i - j);
+			nodes[j] = mas_pop_node(&mas);
+			MT_BUG_ON(mt, mas_allocated(&mas) != i - j - 1);
+		}
+
+		while (j) {
+			j--;
+			mas_push_node(&mas, nodes[j]);
+			MT_BUG_ON(mt, mas_allocated(&mas) != i - j);
+		}
+		MT_BUG_ON(mt, mas_allocated(&mas) != i);
+		for (j = 0; j <= i/2; j++) {
+			MT_BUG_ON(mt, mas_allocated(&mas) != i - j);
+			mn = mas_pop_node(&mas);
+			MT_BUG_ON(mt, not_empty(mn));
+			ma_free_rcu(mn);
+			MT_BUG_ON(mt, mas_allocated(&mas) != i - j - 1);
+		}
+		MT_BUG_ON(mt, mas_nomem(&mas, GFP_KERNEL));
+
+	}
+
+	/* Set allocation request. */
+	total = 500;
+	mas_node_count(&mas, total);
+	/* Drop the lock and allocate the nodes. */
+	mas_nomem(&mas, GFP_KERNEL);
+	MT_BUG_ON(mt, !mas.alloc);
+	i = 1;
+	smn = mas.alloc;
+	while (i < total) {
+		for (j = 0; j < MAPLE_ALLOC_SLOTS; j++) {
+			i++;
+			MT_BUG_ON(mt, !smn->slot[j]);
+			if (i == total)
+				break;
+		}
+		smn = smn->slot[0]; /* next. */
+	}
+	MT_BUG_ON(mt, mas_allocated(&mas) != total);
+	mas_nomem(&mas, GFP_KERNEL); /* Free. */
+
+	MT_BUG_ON(mt, mas_allocated(&mas) != 0);
+	for (i = 1; i < 128; i++) {
+		mas_node_count(&mas, i); /* Request */
+		mas_nomem(&mas, GFP_KERNEL); /* Fill request */
+		MT_BUG_ON(mt, mas_allocated(&mas) != i); /* check request filled */
+		for (j = i; j > 0; j--) { /*Free the requests */
+			mn = mas_pop_node(&mas); /* get the next node. */
+			MT_BUG_ON(mt, mn == NULL);
+			MT_BUG_ON(mt, not_empty(mn));
+			ma_free_rcu(mn);
+		}
+		MT_BUG_ON(mt, mas_allocated(&mas) != 0);
+	}
+
+	for (i = 1; i < MAPLE_NODE_MASK + 1; i++) {
+		MA_STATE(mas2, mt, 0, 0);
+		mas_node_count(&mas, i); /* Request */
+		mas_nomem(&mas, GFP_KERNEL); /* Fill request */
+		MT_BUG_ON(mt, mas_allocated(&mas) != i); /* check request filled */
+		for (j = 1; j <= i; j++) { /* Move the allocations to mas2 */
+			mn = mas_pop_node(&mas); /* get the next node. */
+			MT_BUG_ON(mt, mn == NULL);
+			MT_BUG_ON(mt, not_empty(mn));
+			mas_push_node(&mas2, mn);
+			MT_BUG_ON(mt, mas_allocated(&mas2) != j);
+		}
+		MT_BUG_ON(mt, mas_allocated(&mas) != 0);
+		MT_BUG_ON(mt, mas_allocated(&mas2) != i);
+
+		for (j = i; j > 0; j--) { /*Free the requests */
+			MT_BUG_ON(mt, mas_allocated(&mas2) != j);
+			mn = mas_pop_node(&mas2); /* get the next node. */
+			MT_BUG_ON(mt, mn == NULL);
+			MT_BUG_ON(mt, not_empty(mn));
+			ma_free_rcu(mn);
+		}
+		MT_BUG_ON(mt, mas_allocated(&mas2) != 0);
+	}
+
+
+	MT_BUG_ON(mt, mas_allocated(&mas) != 0);
+	mas_node_count(&mas, MAPLE_ALLOC_SLOTS + 1); /* Request */
+	MT_BUG_ON(mt, mas.node != MA_ERROR(-ENOMEM));
+	MT_BUG_ON(mt, !mas_nomem(&mas, GFP_KERNEL));
+	MT_BUG_ON(mt, mas_allocated(&mas) != MAPLE_ALLOC_SLOTS + 1);
+	MT_BUG_ON(mt, mas.alloc->node_count != MAPLE_ALLOC_SLOTS - 1);
+
+	mn = mas_pop_node(&mas); /* get the next node. */
+	MT_BUG_ON(mt, mn == NULL);
+	MT_BUG_ON(mt, not_empty(mn));
+	MT_BUG_ON(mt, mas_allocated(&mas) != MAPLE_ALLOC_SLOTS);
+	MT_BUG_ON(mt, mas.alloc->node_count != MAPLE_ALLOC_SLOTS - 2);
+
+	mas_push_node(&mas, mn);
+	MT_BUG_ON(mt, mas_allocated(&mas) != MAPLE_ALLOC_SLOTS + 1);
+	MT_BUG_ON(mt, mas.alloc->node_count != MAPLE_ALLOC_SLOTS - 1);
+
+	/* Check the limit of pop/push/pop */
+	mas_node_count(&mas, MAPLE_ALLOC_SLOTS + 2); /* Request */
+	MT_BUG_ON(mt, mas_alloc_req(&mas) != 1);
+	MT_BUG_ON(mt, mas.node != MA_ERROR(-ENOMEM));
+	MT_BUG_ON(mt, !mas_nomem(&mas, GFP_KERNEL));
+	MT_BUG_ON(mt, mas_alloc_req(&mas));
+	MT_BUG_ON(mt, mas.alloc->node_count);
+	MT_BUG_ON(mt, mas_allocated(&mas) != MAPLE_ALLOC_SLOTS + 2);
+	mn = mas_pop_node(&mas);
+	MT_BUG_ON(mt, not_empty(mn));
+	MT_BUG_ON(mt, mas_allocated(&mas) != MAPLE_ALLOC_SLOTS + 1);
+	MT_BUG_ON(mt, mas.alloc->node_count  != MAPLE_ALLOC_SLOTS - 1);
+	mas_push_node(&mas, mn);
+	MT_BUG_ON(mt, mas.alloc->node_count);
+	MT_BUG_ON(mt, mas_allocated(&mas) != MAPLE_ALLOC_SLOTS + 2);
+	mn = mas_pop_node(&mas);
+	MT_BUG_ON(mt, not_empty(mn));
+	ma_free_rcu(mn);
+	for (i = 1; i <= MAPLE_ALLOC_SLOTS + 1; i++) {
+		mn = mas_pop_node(&mas);
+		MT_BUG_ON(mt, not_empty(mn));
+		ma_free_rcu(mn);
+	}
+	MT_BUG_ON(mt, mas_allocated(&mas) != 0);
+
+
+	for (i = 3; i < MAPLE_NODE_MASK * 3; i++) {
+		mas.node = MA_ERROR(-ENOMEM);
+		mas_node_count(&mas, i); /* Request */
+		mas_nomem(&mas, GFP_KERNEL); /* Fill request */
+		mn = mas_pop_node(&mas); /* get the next node. */
+		mas_push_node(&mas, mn); /* put it back */
+		mas_destroy(&mas);
+
+		mas.node = MA_ERROR(-ENOMEM);
+		mas_node_count(&mas, i); /* Request */
+		mas_nomem(&mas, GFP_KERNEL); /* Fill request */
+		mn = mas_pop_node(&mas); /* get the next node. */
+		mn2 = mas_pop_node(&mas); /* get the next node. */
+		mas_push_node(&mas, mn); /* put them back */
+		mas_push_node(&mas, mn2);
+		mas_destroy(&mas);
+
+		mas.node = MA_ERROR(-ENOMEM);
+		mas_node_count(&mas, i); /* Request */
+		mas_nomem(&mas, GFP_KERNEL); /* Fill request */
+		mn = mas_pop_node(&mas); /* get the next node. */
+		mn2 = mas_pop_node(&mas); /* get the next node. */
+		mn3 = mas_pop_node(&mas); /* get the next node. */
+		mas_push_node(&mas, mn); /* put them back */
+		mas_push_node(&mas, mn2);
+		mas_push_node(&mas, mn3);
+		mas_destroy(&mas);
+
+		mas.node = MA_ERROR(-ENOMEM);
+		mas_node_count(&mas, i); /* Request */
+		mas_nomem(&mas, GFP_KERNEL); /* Fill request */
+		mn = mas_pop_node(&mas); /* get the next node. */
+		ma_free_rcu(mn);
+		mas_destroy(&mas);
+
+		mas.node = MA_ERROR(-ENOMEM);
+		mas_node_count(&mas, i); /* Request */
+		mas_nomem(&mas, GFP_KERNEL); /* Fill request */
+		mn = mas_pop_node(&mas); /* get the next node. */
+		ma_free_rcu(mn);
+		mn = mas_pop_node(&mas); /* get the next node. */
+		ma_free_rcu(mn);
+		mn = mas_pop_node(&mas); /* get the next node. */
+		ma_free_rcu(mn);
+		mas_destroy(&mas);
+	}
+
+	mas.node = MA_ERROR(-ENOMEM);
+	mas_node_count(&mas, 5); /* Request */
+	mas_nomem(&mas, GFP_KERNEL); /* Fill request */
+	MT_BUG_ON(mt, mas_allocated(&mas) != 5);
+	mas.node = MA_ERROR(-ENOMEM);
+	mas_node_count(&mas, 10); /* Request */
+	mas_nomem(&mas, GFP_KERNEL); /* Fill request */
+	mas.node = MAS_START;
+	MT_BUG_ON(mt, mas_allocated(&mas) != 10);
+	mas_destroy(&mas);
+
+	mas.node = MA_ERROR(-ENOMEM);
+	mas_node_count(&mas, MAPLE_ALLOC_SLOTS - 1); /* Request */
+	mas_nomem(&mas, GFP_KERNEL); /* Fill request */
+	MT_BUG_ON(mt, mas_allocated(&mas) != MAPLE_ALLOC_SLOTS - 1);
+	mas.node = MA_ERROR(-ENOMEM);
+	mas_node_count(&mas, 10 + MAPLE_ALLOC_SLOTS - 1); /* Request */
+	mas_nomem(&mas, GFP_KERNEL); /* Fill request */
+	mas.node = MAS_START;
+	MT_BUG_ON(mt, mas_allocated(&mas) != 10 + MAPLE_ALLOC_SLOTS - 1);
+	mas_destroy(&mas);
+
+	mtree_unlock(mt);
+}
+
+static noinline void check_rev_seq(struct maple_tree *mt, unsigned long max,
+		bool verbose)
+{
+	unsigned long i = max, j;
+
+	MT_BUG_ON(mt, !mtree_empty(mt));
+
+	mt_zero_nr_tallocated();
+	while (i) {
+		MT_BUG_ON(mt, mtree_insert_index(mt, i, GFP_KERNEL));
+		for (j = i; j <= max; j++)
+			check_index_load(mt, j);
+
+		check_load(mt, i - 1, NULL);
+		mt_set_in_rcu(mt);
+		MT_BUG_ON(mt, !mt_height(mt));
+		mt_clear_in_rcu(mt);
+		MT_BUG_ON(mt, !mt_height(mt));
+		i--;
+	}
+	check_load(mt, max + 1, NULL);
+
+	if (verbose) {
+		rcu_barrier();
+		mt_dump(mt);
+		pr_info(" %s test of 0-%lu %luK in %d active (%d total)\n",
+			__func__, max, mt_get_alloc_size()/1024, mt_nr_allocated(),
+			mt_nr_tallocated());
+	}
+}
+
+static noinline void check_seq(struct maple_tree *mt, unsigned long max,
+		bool verbose)
+{
+	unsigned long i, j;
+
+	MT_BUG_ON(mt, !mtree_empty(mt));
+
+	mt_zero_nr_tallocated();
+	for (i = 0; i <= max; i++) {
+		MT_BUG_ON(mt, mtree_insert_index(mt, i, GFP_KERNEL));
+		for (j = 0; j <= i; j++)
+			check_index_load(mt, j);
+
+		if (i)
+			MT_BUG_ON(mt, !mt_height(mt));
+		check_load(mt, i + 1, NULL);
+	}
+	if (verbose) {
+		rcu_barrier();
+		mt_dump(mt);
+		pr_info(" seq test of 0-%lu %luK in %d active (%d total)\n",
+			max, mt_get_alloc_size()/1024, mt_nr_allocated(),
+			mt_nr_tallocated());
+	}
+}
+
+static noinline void check_lb_not_empty(struct maple_tree *mt)
+{
+	unsigned long i, j;
+	unsigned long huge = 4000UL * 1000 * 1000;
+
+
+	i = huge;
+	while (i > 4096) {
+		check_insert(mt, i, (void *) i);
+		for (j = huge; j >= i; j /= 2) {
+			check_load(mt, j-1, NULL);
+			check_load(mt, j, (void *) j);
+			check_load(mt, j+1, NULL);
+		}
+		i /= 2;
+	}
+	mtree_destroy(mt);
+}
+
+static noinline void check_lower_bound_split(struct maple_tree *mt)
+{
+	MT_BUG_ON(mt, !mtree_empty(mt));
+	check_lb_not_empty(mt);
+}
+
+static noinline void check_upper_bound_split(struct maple_tree *mt)
+{
+	unsigned long i, j;
+	unsigned long huge = 4000UL * 1000 * 1000;
+
+	MT_BUG_ON(mt, !mtree_empty(mt));
+
+	i = 4096;
+	while (i < huge) {
+		check_insert(mt, i, (void *) i);
+		for (j = i; j >= huge; j *= 2) {
+			check_load(mt, j-1, NULL);
+			check_load(mt, j, (void *) j);
+			check_load(mt, j+1, NULL);
+		}
+		i *= 2;
+	}
+	mtree_destroy(mt);
+}
+
+static noinline void check_mid_split(struct maple_tree *mt)
+{
+	unsigned long huge = 8000UL * 1000 * 1000;
+
+	check_insert(mt, huge, (void *) huge);
+	check_insert(mt, 0, xa_mk_value(0));
+	check_lb_not_empty(mt);
+}
+
+static noinline void check_rev_find(struct maple_tree *mt)
+{
+	int i, nr_entries = 200;
+	void *val;
+	MA_STATE(mas, mt, 0, 0);
+
+	for (i = 0; i <= nr_entries; i++)
+		mtree_store_range(mt, i*10, i*10 + 5,
+				  xa_mk_value(i), GFP_KERNEL);
+
+	mas_set(&mas, 1000);
+	val = mas_find_rev(&mas, 1000);
+	MT_BUG_ON(mt, val != xa_mk_value(100));
+	val = mas_find_rev(&mas, 1000);
+	MT_BUG_ON(mt, val != NULL);
+
+	mas_set(&mas, 999);
+	val = mas_find_rev(&mas, 997);
+	MT_BUG_ON(mt, val != NULL);
+
+	mas_set(&mas, 1000);
+	val = mas_find_rev(&mas, 900);
+	MT_BUG_ON(mt, val != xa_mk_value(100));
+	val = mas_find_rev(&mas, 900);
+	MT_BUG_ON(mt, val != xa_mk_value(99));
+
+	mas_set(&mas, 20);
+	val = mas_find_rev(&mas, 0);
+	MT_BUG_ON(mt, val != xa_mk_value(2));
+	val = mas_find_rev(&mas, 0);
+	MT_BUG_ON(mt, val != xa_mk_value(1));
+	val = mas_find_rev(&mas, 0);
+	MT_BUG_ON(mt, val != xa_mk_value(0));
+	val = mas_find_rev(&mas, 0);
+	MT_BUG_ON(mt, val != NULL);
+}
+
+static noinline void check_find(struct maple_tree *mt)
+{
+	unsigned long val = 0;
+	unsigned long count = 20;
+	unsigned long max;
+	unsigned long last = 0, index = 0;
+	void *entry, *entry2;
+
+	MA_STATE(mas, mt, 0, 0);
+
+	/* Insert 0. */
+	MT_BUG_ON(mt, mtree_insert_index(mt, val++, GFP_KERNEL));
+
+	for (int i = 0; i <= count; i++) {
+		if (val != 64)
+			MT_BUG_ON(mt, mtree_insert_index(mt, val, GFP_KERNEL));
+		else
+			MT_BUG_ON(mt, mtree_insert(mt, val,
+				XA_ZERO_ENTRY, GFP_KERNEL));
+
+		val <<= 2;
+	}
+
+	val = 0;
+	mas_set(&mas, val);
+	mas_lock(&mas);
+	while ((entry = mas_find(&mas, 268435456)) != NULL) {
+		if (val != 64)
+			MT_BUG_ON(mt, xa_mk_value(val) != entry);
+		else
+			MT_BUG_ON(mt, entry != XA_ZERO_ENTRY);
+
+		val <<= 2;
+		/* For zero check. */
+		if (!val)
+			val = 1;
+	}
+	mas_unlock(&mas);
+
+	val = 0;
+	mas_set(&mas, val);
+	mas_lock(&mas);
+	mas_for_each(&mas, entry, ULONG_MAX) {
+		if (val != 64)
+			MT_BUG_ON(mt, xa_mk_value(val) != entry);
+		else
+			MT_BUG_ON(mt, entry != XA_ZERO_ENTRY);
+		val <<= 2;
+		/* For zero check. */
+		if (!val)
+			val = 1;
+	}
+	mas_unlock(&mas);
+
+	/* Test mas_pause */
+	val = 0;
+	mas_set(&mas, val);
+	mas_lock(&mas);
+	mas_for_each(&mas, entry, ULONG_MAX) {
+		if (val != 64)
+			MT_BUG_ON(mt, xa_mk_value(val) != entry);
+		else
+			MT_BUG_ON(mt, entry != XA_ZERO_ENTRY);
+		val <<= 2;
+		/* For zero check. */
+		if (!val)
+			val = 1;
+
+		mas_pause(&mas);
+		mas_unlock(&mas);
+		mas_lock(&mas);
+	}
+	mas_unlock(&mas);
+
+	val = 0;
+	max = 300; /* A value big enough to include XA_ZERO_ENTRY at 64. */
+	mt_for_each(mt, entry, index, max) {
+		MT_BUG_ON(mt, xa_mk_value(val) != entry);
+		val <<= 2;
+		if (val == 64) /* Skip zero entry. */
+			val <<= 2;
+		/* For zero check. */
+		if (!val)
+			val = 1;
+	}
+
+	val = 0;
+	max = 0;
+	index = 0;
+	MT_BUG_ON(mt, mtree_insert_index(mt, ULONG_MAX, GFP_KERNEL));
+	mt_for_each(mt, entry, index, ULONG_MAX) {
+		if (val == 4398046511104)
+			MT_BUG_ON(mt, entry !=
+					xa_mk_value(ULONG_MAX & LONG_MAX));
+		else
+			MT_BUG_ON(mt, xa_mk_value(val) != entry);
+		val <<= 2;
+		if (val == 64) /* Skip zero entry. */
+			val <<= 2;
+		/* For zero check. */
+		if (!val)
+			val = 1;
+		max++;
+		MT_BUG_ON(mt, max > 25);
+	}
+	mtree_erase_index(mt, ULONG_MAX);
+
+	mas_reset(&mas);
+	index = 17;
+	entry = mt_find(mt, &index, 512);
+	MT_BUG_ON(mt, xa_mk_value(256) != entry);
+
+	mas_reset(&mas);
+	index = 17;
+	entry = mt_find(mt, &index, 20);
+	MT_BUG_ON(mt, entry != NULL);
+
+
+	/* Range check.. */
+	/* Insert ULONG_MAX */
+	MT_BUG_ON(mt, mtree_insert_index(mt, ULONG_MAX, GFP_KERNEL));
+
+	val = 0;
+	mas_set(&mas, 0);
+	mas_lock(&mas);
+	mas_for_each(&mas, entry, ULONG_MAX) {
+		if (val == 64)
+			MT_BUG_ON(mt, entry != XA_ZERO_ENTRY);
+		else if (val == 4398046511104)
+			MT_BUG_ON(mt, entry != xa_mk_value(ULONG_MAX & LONG_MAX));
+		else
+			MT_BUG_ON(mt, xa_mk_value(val) != entry);
+		val <<= 2;
+
+		/* For zero check. */
+		if (!val)
+			val = 1;
+		mas_pause(&mas);
+		mas_unlock(&mas);
+		mas_lock(&mas);
+	}
+	mas_unlock(&mas);
+
+	mas_set(&mas, 1048576);
+	mas_lock(&mas);
+	entry = mas_find(&mas, 1048576);
+	mas_unlock(&mas);
+	MT_BUG_ON(mas.tree, entry == NULL);
+
+	/*
+	 * Find last value.
+	 * 1. get the expected value, leveraging the existence of an end entry
+	 * 2. delete end entry
+	 * 3. find the last value but searching for ULONG_MAX and then using
+	 * prev
+	 */
+	/* First, get the expected result. */
+	mas_lock(&mas);
+	mas_reset(&mas);
+	mas.index = ULONG_MAX; /* start at max.. */
+	entry = mas_find(&mas, ULONG_MAX);
+	entry = mas_prev(&mas, 0);
+	index = mas.index;
+	last = mas.last;
+
+	/* Erase the last entry. */
+	mas_reset(&mas);
+	mas.index = ULONG_MAX;
+	mas.last = ULONG_MAX;
+	mas_erase(&mas);
+
+	/* Get the previous value from MAS_START */
+	mas_reset(&mas);
+	entry2 = mas_prev(&mas, 0);
+
+	/* Check results. */
+	MT_BUG_ON(mt, entry != entry2);
+	MT_BUG_ON(mt, index != mas.index);
+	MT_BUG_ON(mt, last != mas.last);
+
+
+	mas.node = MAS_NONE;
+	mas.index = ULONG_MAX;
+	mas.last = ULONG_MAX;
+	entry2 = mas_prev(&mas, 0);
+	MT_BUG_ON(mt, entry != entry2);
+
+	mas_set(&mas, 0);
+	MT_BUG_ON(mt, mas_prev(&mas, 0) != NULL);
+
+	mas_unlock(&mas);
+	mtree_destroy(mt);
+}
+
+static noinline void check_find_2(struct maple_tree *mt)
+{
+	unsigned long i, j;
+	void *entry;
+
+	MA_STATE(mas, mt, 0, 0);
+	rcu_read_lock();
+	mas_for_each(&mas, entry, ULONG_MAX)
+		MT_BUG_ON(mt, true);
+	rcu_read_unlock();
+
+	for (i = 0; i < 256; i++) {
+		mtree_insert_index(mt, i, GFP_KERNEL);
+		j = 0;
+		mas_set(&mas, 0);
+		rcu_read_lock();
+		mas_for_each(&mas, entry, ULONG_MAX) {
+			MT_BUG_ON(mt, entry != xa_mk_value(j));
+			j++;
+		}
+		rcu_read_unlock();
+		MT_BUG_ON(mt, j != i + 1);
+	}
+
+	for (i = 0; i < 256; i++) {
+		mtree_erase_index(mt, i);
+		j = i + 1;
+		mas_set(&mas, 0);
+		rcu_read_lock();
+		mas_for_each(&mas, entry, ULONG_MAX) {
+			if (xa_is_zero(entry))
+				continue;
+
+			MT_BUG_ON(mt, entry != xa_mk_value(j));
+			j++;
+		}
+		rcu_read_unlock();
+		MT_BUG_ON(mt, j != 256);
+	}
+
+	/*MT_BUG_ON(mt, !mtree_empty(mt)); */
+}
+
+#define erase_ptr(i) entry[i%2]
+#define erase_check_load(mt, i) check_load(mt, set[i], entry[i%2])
+#define erase_check_insert(mt, i) check_insert(mt, set[i], entry[i%2])
+#define erase_check_erase(mt, i) check_erase(mt, set[i], entry[i%2])
+
+static noinline void check_erase_testset(struct maple_tree *mt)
+{
+	unsigned long set[] = { 5015, 5014, 5017, 25, 1000,
+				1001, 1002, 1003, 1005, 0,
+				6003, 6002, 6008, 6012, 6015,
+				7003, 7002, 7008, 7012, 7015,
+				8003, 8002, 8008, 8012, 8015,
+				9003, 9002, 9008, 9012, 9015,
+				10003, 10002, 10008, 10012, 10015,
+				11003, 11002, 11008, 11012, 11015,
+				12003, 12002, 12008, 12012, 12015,
+				13003, 13002, 13008, 13012, 13015,
+				14003, 14002, 14008, 14012, 14015,
+				15003, 15002, 15008, 15012, 15015,
+			      };
+
+
+	void *ptr = &set;
+	void *entry[2] = { ptr, mt };
+	void *root_node;
+
+
+	rcu_register_thread();
+	mt_set_in_rcu(mt);
+	for (int i = 0; i < 4; i++)
+		erase_check_insert(mt, i);
+	for (int i = 0; i < 4; i++)
+		erase_check_load(mt, i);
+
+	mt_set_non_kernel(2);
+	erase_check_erase(mt, 1);
+	erase_check_load(mt, 0);
+	check_load(mt, set[1], NULL);
+	for (int i = 2; i < 4; i++)
+		erase_check_load(mt, i);
+
+
+	erase_check_erase(mt, 2);
+	erase_check_load(mt, 0);
+	check_load(mt, set[1], NULL);
+	check_load(mt, set[2], NULL);
+
+	erase_check_insert(mt, 1);
+	erase_check_insert(mt, 2);
+
+	for (int i = 0; i < 4; i++)
+		erase_check_load(mt, i);
+
+	/* Check erase and load without an allocation. */
+	erase_check_load(mt, 3);
+	erase_check_erase(mt, 1);
+	erase_check_load(mt, 0);
+	check_load(mt, set[1], NULL);
+	for (int i = 2; i < 4; i++)
+		erase_check_load(mt, i);
+
+	/*
+	 * Set the newly erased node.  This will produce a different allocated
+	 * node to avoid busy slots.
+	 */
+	root_node = mt->ma_root;
+	erase_check_insert(mt, 1);
+
+	erase_check_load(mt, 0);
+	check_load(mt, 5016, NULL);
+	erase_check_load(mt, 1);
+	check_load(mt, 5013, NULL);
+	erase_check_load(mt, 2);
+	check_load(mt, 5018, NULL);
+	erase_check_load(mt, 3);
+
+	erase_check_erase(mt, 2); /* erase 5017 to check append */
+	erase_check_load(mt, 0);
+	check_load(mt, 5016, NULL);
+	erase_check_load(mt, 1);
+	check_load(mt, 5013, NULL);
+	check_load(mt, set[2], NULL);
+	check_load(mt, 5018, NULL);
+
+	erase_check_load(mt, 3);
+
+	root_node = mt->ma_root;
+	erase_check_insert(mt, 2);
+
+	erase_check_load(mt, 0);
+	check_load(mt, 5016, NULL);
+	erase_check_load(mt, 1);
+	check_load(mt, 5013, NULL);
+	erase_check_load(mt, 2);
+	check_load(mt, 5018, NULL);
+	erase_check_load(mt, 3);
+
+	mt_set_non_kernel(1);
+	erase_check_erase(mt, 2); /* erase 5017 to check append */
+	erase_check_load(mt, 0);
+	check_load(mt, 5016, NULL);
+	check_load(mt, set[2], NULL);
+	erase_check_erase(mt, 0); /* erase 5015 to check append */
+	check_load(mt, set[0], NULL);
+	check_load(mt, 5016, NULL);
+	erase_check_insert(mt, 4); /* 1000 < Should not split. */
+	check_load(mt, set[0], NULL);
+	check_load(mt, 5016, NULL);
+	erase_check_load(mt, 1);
+	check_load(mt, 5013, NULL);
+	check_load(mt, set[2], NULL);
+	check_load(mt, 5018, NULL);
+	erase_check_load(mt, 4);
+	check_load(mt, 999, NULL);
+	check_load(mt, 1001, NULL);
+	erase_check_load(mt, 4);
+	if (mt_in_rcu(mt))
+		MT_BUG_ON(mt, root_node == mt->ma_root);
+	else
+		MT_BUG_ON(mt, root_node != mt->ma_root);
+
+	/* Should not have split. */
+	MT_BUG_ON(mt, !mte_is_leaf(mt->ma_root));
+
+
+	/* Coalesce testing */
+	erase_check_insert(mt, 0);
+	erase_check_insert(mt, 2);
+
+	for (int i = 5; i < 25; i++) {
+		erase_check_insert(mt, i);
+		for (int j = i; j >= 0; j--)
+			erase_check_load(mt, j);
+	}
+
+	erase_check_erase(mt, 14); /*6015 */
+	for (int i = 0; i < 25; i++) {
+		if (i == 14)
+			check_load(mt, set[i], NULL);
+		else
+			erase_check_load(mt, i);
+	}
+	erase_check_erase(mt, 16); /*7002 */
+	for (int i = 0; i < 25; i++) {
+		if (i == 16 || i == 14)
+			check_load(mt, set[i], NULL);
+		else
+			erase_check_load(mt, i);
+	}
+