v4.19.13 snapshot.
diff --git a/lib/test_ida.c b/lib/test_ida.c
new file mode 100644
index 0000000..b068806
--- /dev/null
+++ b/lib/test_ida.c
@@ -0,0 +1,177 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * test_ida.c: Test the IDA API
+ * Copyright (c) 2016-2018 Microsoft Corporation
+ * Copyright (c) 2018 Oracle Corporation
+ * Author: Matthew Wilcox <willy@infradead.org>
+ */
+
+#include <linux/idr.h>
+#include <linux/module.h>
+
+static unsigned int tests_run;
+static unsigned int tests_passed;
+
+#ifdef __KERNEL__
+void ida_dump(struct ida *ida) { }
+#endif
+#define IDA_BUG_ON(ida, x) do { \
+ tests_run++; \
+ if (x) { \
+ ida_dump(ida); \
+ dump_stack(); \
+ } else { \
+ tests_passed++; \
+ } \
+} while (0)
+
+/*
+ * Straightforward checks that allocating and freeing IDs work.
+ */
+static void ida_check_alloc(struct ida *ida)
+{
+ int i, id;
+
+ for (i = 0; i < 10000; i++)
+ IDA_BUG_ON(ida, ida_alloc(ida, GFP_KERNEL) != i);
+
+ ida_free(ida, 20);
+ ida_free(ida, 21);
+ for (i = 0; i < 3; i++) {
+ id = ida_alloc(ida, GFP_KERNEL);
+ IDA_BUG_ON(ida, id < 0);
+ if (i == 2)
+ IDA_BUG_ON(ida, id != 10000);
+ }
+
+ for (i = 0; i < 5000; i++)
+ ida_free(ida, i);
+
+ IDA_BUG_ON(ida, ida_alloc_min(ida, 5000, GFP_KERNEL) != 10001);
+ ida_destroy(ida);
+
+ IDA_BUG_ON(ida, !ida_is_empty(ida));
+}
+
+/* Destroy an IDA with a single entry at @base */
+static void ida_check_destroy_1(struct ida *ida, unsigned int base)
+{
+ IDA_BUG_ON(ida, ida_alloc_min(ida, base, GFP_KERNEL) != base);
+ IDA_BUG_ON(ida, ida_is_empty(ida));
+ ida_destroy(ida);
+ IDA_BUG_ON(ida, !ida_is_empty(ida));
+}
+
+/* Check that ida_destroy and ida_is_empty work */
+static void ida_check_destroy(struct ida *ida)
+{
+ /* Destroy an already-empty IDA */
+ IDA_BUG_ON(ida, !ida_is_empty(ida));
+ ida_destroy(ida);
+ IDA_BUG_ON(ida, !ida_is_empty(ida));
+
+ ida_check_destroy_1(ida, 0);
+ ida_check_destroy_1(ida, 1);
+ ida_check_destroy_1(ida, 1023);
+ ida_check_destroy_1(ida, 1024);
+ ida_check_destroy_1(ida, 12345678);
+}
+
+/*
+ * Check what happens when we fill a leaf and then delete it. This may
+ * discover mishandling of IDR_FREE.
+ */
+static void ida_check_leaf(struct ida *ida, unsigned int base)
+{
+ unsigned long i;
+
+ for (i = 0; i < IDA_BITMAP_BITS; i++) {
+ IDA_BUG_ON(ida, ida_alloc_min(ida, base, GFP_KERNEL) !=
+ base + i);
+ }
+
+ ida_destroy(ida);
+ IDA_BUG_ON(ida, !ida_is_empty(ida));
+
+ IDA_BUG_ON(ida, ida_alloc(ida, GFP_KERNEL) != 0);
+ IDA_BUG_ON(ida, ida_is_empty(ida));
+ ida_free(ida, 0);
+ IDA_BUG_ON(ida, !ida_is_empty(ida));
+}
+
+/*
+ * Check allocations up to and slightly above the maximum allowed (2^31-1) ID.
+ * Allocating up to 2^31-1 should succeed, and then allocating the next one
+ * should fail.
+ */
+static void ida_check_max(struct ida *ida)
+{
+ unsigned long i, j;
+
+ for (j = 1; j < 65537; j *= 2) {
+ unsigned long base = (1UL << 31) - j;
+ for (i = 0; i < j; i++) {
+ IDA_BUG_ON(ida, ida_alloc_min(ida, base, GFP_KERNEL) !=
+ base + i);
+ }
+ IDA_BUG_ON(ida, ida_alloc_min(ida, base, GFP_KERNEL) !=
+ -ENOSPC);
+ ida_destroy(ida);
+ IDA_BUG_ON(ida, !ida_is_empty(ida));
+ }
+}
+
+/*
+ * Check handling of conversions between exceptional entries and full bitmaps.
+ */
+static void ida_check_conv(struct ida *ida)
+{
+ unsigned long i;
+
+ for (i = 0; i < IDA_BITMAP_BITS * 2; i += IDA_BITMAP_BITS) {
+ IDA_BUG_ON(ida, ida_alloc_min(ida, i + 1, GFP_KERNEL) != i + 1);
+ IDA_BUG_ON(ida, ida_alloc_min(ida, i + BITS_PER_LONG,
+ GFP_KERNEL) != i + BITS_PER_LONG);
+ ida_free(ida, i + 1);
+ ida_free(ida, i + BITS_PER_LONG);
+ IDA_BUG_ON(ida, !ida_is_empty(ida));
+ }
+
+ for (i = 0; i < IDA_BITMAP_BITS * 2; i++)
+ IDA_BUG_ON(ida, ida_alloc(ida, GFP_KERNEL) != i);
+ for (i = IDA_BITMAP_BITS * 2; i > 0; i--)
+ ida_free(ida, i - 1);
+ IDA_BUG_ON(ida, !ida_is_empty(ida));
+
+ for (i = 0; i < IDA_BITMAP_BITS + BITS_PER_LONG - 4; i++)
+ IDA_BUG_ON(ida, ida_alloc(ida, GFP_KERNEL) != i);
+ for (i = IDA_BITMAP_BITS + BITS_PER_LONG - 4; i > 0; i--)
+ ida_free(ida, i - 1);
+ IDA_BUG_ON(ida, !ida_is_empty(ida));
+}
+
+static DEFINE_IDA(ida);
+
+static int ida_checks(void)
+{
+ IDA_BUG_ON(&ida, !ida_is_empty(&ida));
+ ida_check_alloc(&ida);
+ ida_check_destroy(&ida);
+ ida_check_leaf(&ida, 0);
+ ida_check_leaf(&ida, 1024);
+ ida_check_leaf(&ida, 1024 * 64);
+ ida_check_max(&ida);
+ ida_check_conv(&ida);
+
+ printk("IDA: %u of %u tests passed\n", tests_passed, tests_run);
+ return (tests_run != tests_passed) ? 0 : -EINVAL;
+}
+
+static void ida_exit(void)
+{
+}
+
+module_init(ida_checks);
+module_exit(ida_exit);
+MODULE_AUTHOR("Matthew Wilcox <willy@infradead.org>");
+MODULE_LICENSE("GPL");