1 files changed, 23 insertions, 0 deletions

diff --git a/lib/test_ida.c b/lib/test_ida.c
index 1988f91a20c8..44174ec9f5bf 100644
--- a/lib/test_ida.c
+++ b/lib/test_ida.c
@@ -47,6 +47,28 @@ static void ida_check_leaf(struct ida *ida, unsigned int base)
         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));
+        }
+}
+
 static int ida_checks(void)
 {
         DEFINE_IDA(ida);
@@ -55,6 +77,7 @@ static int ida_checks(void)
         ida_check_leaf(&ida, 0);
         ida_check_leaf(&ida, 1024);
         ida_check_leaf(&ida, 1024 * 64);
+        ida_check_max(&ida);
 
         printk("IDA: %u of %u tests passed\n", tests_passed, tests_run);
         return (tests_run != tests_passed) ? 0 : -EINVAL;