scftorture: Count single_rpc offline failures in statistics outputgrafted

scf_torture_stats_print() aggregates each invoker thread's counters
into a local scf_statistics structure before printing, but the
n_single_rpc_ofl field is missing from the aggregation loop.  As a
result, the "single_rpc_ofl" value printed in the statistics line is
always zero, even when smp_call_function_single() invocations for the
RPC test have failed due to offline CPUs and been counted by the
invoker threads.

Add the missing accumulation so that the printed value reflects the
actual counts.

Signed-off-by: Joel Fernandes <joelagnelf@nvidia.com>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>

1 files changed, 116 insertions, 0 deletions

diff --git a/lib/test_ref_tracker.c b/lib/test_ref_tracker.c
new file mode 100644
index 000000000..b983ceb12
--- /dev/null
+++ b/lib/test_ref_tracker.c
@@ -0,0 +1,116 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Reference tracker self test.
+ *
+ * Copyright (c) 2021 Eric Dumazet <edumazet@google.com>
+ */
+#include <linux/init.h>
+#include <linux/module.h>
+#include <linux/delay.h>
+#include <linux/ref_tracker.h>
+#include <linux/slab.h>
+#include <linux/timer.h>
+
+static struct ref_tracker_dir ref_dir;
+static struct ref_tracker *tracker[20];
+
+#define TRT_ALLOC(X) static noinline void 				\
+	alloctest_ref_tracker_alloc##X(struct ref_tracker_dir *dir, 	\
+				    struct ref_tracker **trackerp)	\
+	{								\
+		ref_tracker_alloc(dir, trackerp, GFP_KERNEL);		\
+	}
+
+TRT_ALLOC(1)
+TRT_ALLOC(2)
+TRT_ALLOC(3)
+TRT_ALLOC(4)
+TRT_ALLOC(5)
+TRT_ALLOC(6)
+TRT_ALLOC(7)
+TRT_ALLOC(8)
+TRT_ALLOC(9)
+TRT_ALLOC(10)
+TRT_ALLOC(11)
+TRT_ALLOC(12)
+TRT_ALLOC(13)
+TRT_ALLOC(14)
+TRT_ALLOC(15)
+TRT_ALLOC(16)
+TRT_ALLOC(17)
+TRT_ALLOC(18)
+TRT_ALLOC(19)
+
+#undef TRT_ALLOC
+
+static noinline void
+alloctest_ref_tracker_free(struct ref_tracker_dir *dir,
+			   struct ref_tracker **trackerp)
+{
+	ref_tracker_free(dir, trackerp);
+}
+
+
+static struct timer_list test_ref_tracker_timer;
+static atomic_t test_ref_timer_done = ATOMIC_INIT(0);
+
+static void test_ref_tracker_timer_func(struct timer_list *t)
+{
+	ref_tracker_alloc(&ref_dir, &tracker[0], GFP_ATOMIC);
+	atomic_set(&test_ref_timer_done, 1);
+}
+
+static int __init test_ref_tracker_init(void)
+{
+	int i;
+
+	ref_tracker_dir_init(&ref_dir, 100, "selftest");
+
+	timer_setup(&test_ref_tracker_timer, test_ref_tracker_timer_func, 0);
+	mod_timer(&test_ref_tracker_timer, jiffies + 1);
+
+	alloctest_ref_tracker_alloc1(&ref_dir, &tracker[1]);
+	alloctest_ref_tracker_alloc2(&ref_dir, &tracker[2]);
+	alloctest_ref_tracker_alloc3(&ref_dir, &tracker[3]);
+	alloctest_ref_tracker_alloc4(&ref_dir, &tracker[4]);
+	alloctest_ref_tracker_alloc5(&ref_dir, &tracker[5]);
+	alloctest_ref_tracker_alloc6(&ref_dir, &tracker[6]);
+	alloctest_ref_tracker_alloc7(&ref_dir, &tracker[7]);
+	alloctest_ref_tracker_alloc8(&ref_dir, &tracker[8]);
+	alloctest_ref_tracker_alloc9(&ref_dir, &tracker[9]);
+	alloctest_ref_tracker_alloc10(&ref_dir, &tracker[10]);
+	alloctest_ref_tracker_alloc11(&ref_dir, &tracker[11]);
+	alloctest_ref_tracker_alloc12(&ref_dir, &tracker[12]);
+	alloctest_ref_tracker_alloc13(&ref_dir, &tracker[13]);
+	alloctest_ref_tracker_alloc14(&ref_dir, &tracker[14]);
+	alloctest_ref_tracker_alloc15(&ref_dir, &tracker[15]);
+	alloctest_ref_tracker_alloc16(&ref_dir, &tracker[16]);
+	alloctest_ref_tracker_alloc17(&ref_dir, &tracker[17]);
+	alloctest_ref_tracker_alloc18(&ref_dir, &tracker[18]);
+	alloctest_ref_tracker_alloc19(&ref_dir, &tracker[19]);
+
+	/* free all trackers but first 0 and 1. */
+	for (i = 2; i < ARRAY_SIZE(tracker); i++)
+		alloctest_ref_tracker_free(&ref_dir, &tracker[i]);
+
+	/* Attempt to free an already freed tracker. */
+	alloctest_ref_tracker_free(&ref_dir, &tracker[2]);
+
+	while (!atomic_read(&test_ref_timer_done))
+		msleep(1);
+
+	/* This should warn about tracker[0] & tracker[1] being not freed. */
+	ref_tracker_dir_exit(&ref_dir);
+
+	return 0;
+}
+
+static void __exit test_ref_tracker_exit(void)
+{
+}
+
+module_init(test_ref_tracker_init);
+module_exit(test_ref_tracker_exit);
+
+MODULE_DESCRIPTION("Reference tracker self test");
+MODULE_LICENSE("GPL v2");