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, 156 insertions, 0 deletions

diff --git a/lib/interval_tree.c b/lib/interval_tree.c
new file mode 100644
index 000000000..9ceb084b6
--- /dev/null
+++ b/lib/interval_tree.c
@@ -0,0 +1,156 @@
+// SPDX-License-Identifier: GPL-2.0-only
+#include <linux/interval_tree.h>
+#include <linux/interval_tree_generic.h>
+#include <linux/compiler.h>
+#include <linux/export.h>
+
+#define START(node) ((node)->start)
+#define LAST(node)  ((node)->last)
+
+INTERVAL_TREE_DEFINE(struct interval_tree_node, rb,
+		     unsigned long, __subtree_last,
+		     START, LAST,, interval_tree)
+
+EXPORT_SYMBOL_GPL(interval_tree_insert);
+EXPORT_SYMBOL_GPL(interval_tree_remove);
+EXPORT_SYMBOL_GPL(interval_tree_subtree_search);
+EXPORT_SYMBOL_GPL(interval_tree_iter_first);
+EXPORT_SYMBOL_GPL(interval_tree_iter_next);
+
+#ifdef CONFIG_INTERVAL_TREE_SPAN_ITER
+/*
+ * Roll nodes[1] into nodes[0] by advancing nodes[1] to the end of a contiguous
+ * span of nodes. This makes nodes[0]->last the end of that contiguous used span
+ * of indexes that started at the original nodes[1]->start.
+ *
+ * If there is an interior hole, nodes[1] is now the first node starting the
+ * next used span. A hole span is between nodes[0]->last and nodes[1]->start.
+ *
+ * If there is a tailing hole, nodes[1] is now NULL. A hole span is between
+ * nodes[0]->last and last_index.
+ *
+ * If the contiguous used range span to last_index, nodes[1] is set to NULL.
+ */
+static void
+interval_tree_span_iter_next_gap(struct interval_tree_span_iter *state)
+{
+	struct interval_tree_node *cur = state->nodes[1];
+
+	state->nodes[0] = cur;
+	do {
+		if (cur->last > state->nodes[0]->last)
+			state->nodes[0] = cur;
+		cur = interval_tree_iter_next(cur, state->first_index,
+					      state->last_index);
+	} while (cur && (state->nodes[0]->last >= cur->start ||
+			 state->nodes[0]->last + 1 == cur->start));
+	state->nodes[1] = cur;
+}
+
+void interval_tree_span_iter_first(struct interval_tree_span_iter *iter,
+				   struct rb_root_cached *itree,
+				   unsigned long first_index,
+				   unsigned long last_index)
+{
+	iter->first_index = first_index;
+	iter->last_index = last_index;
+	iter->nodes[0] = NULL;
+	iter->nodes[1] =
+		interval_tree_iter_first(itree, first_index, last_index);
+	if (!iter->nodes[1]) {
+		/* No nodes intersect the span, whole span is hole */
+		iter->start_hole = first_index;
+		iter->last_hole = last_index;
+		iter->is_hole = 1;
+		return;
+	}
+	if (iter->nodes[1]->start > first_index) {
+		/* Leading hole on first iteration */
+		iter->start_hole = first_index;
+		iter->last_hole = iter->nodes[1]->start - 1;
+		iter->is_hole = 1;
+		interval_tree_span_iter_next_gap(iter);
+		return;
+	}
+
+	/* Starting inside a used */
+	iter->start_used = first_index;
+	iter->is_hole = 0;
+	interval_tree_span_iter_next_gap(iter);
+	iter->last_used = iter->nodes[0]->last;
+	if (iter->last_used >= last_index) {
+		iter->last_used = last_index;
+		iter->nodes[0] = NULL;
+		iter->nodes[1] = NULL;
+	}
+}
+EXPORT_SYMBOL_GPL(interval_tree_span_iter_first);
+
+void interval_tree_span_iter_next(struct interval_tree_span_iter *iter)
+{
+	if (!iter->nodes[0] && !iter->nodes[1]) {
+		iter->is_hole = -1;
+		return;
+	}
+
+	if (iter->is_hole) {
+		iter->start_used = iter->last_hole + 1;
+		iter->last_used = iter->nodes[0]->last;
+		if (iter->last_used >= iter->last_index) {
+			iter->last_used = iter->last_index;
+			iter->nodes[0] = NULL;
+			iter->nodes[1] = NULL;
+		}
+		iter->is_hole = 0;
+		return;
+	}
+
+	if (!iter->nodes[1]) {
+		/* Trailing hole */
+		iter->start_hole = iter->nodes[0]->last + 1;
+		iter->last_hole = iter->last_index;
+		iter->nodes[0] = NULL;
+		iter->is_hole = 1;
+		return;
+	}
+
+	/* must have both nodes[0] and [1], interior hole */
+	iter->start_hole = iter->nodes[0]->last + 1;
+	iter->last_hole = iter->nodes[1]->start - 1;
+	iter->is_hole = 1;
+	interval_tree_span_iter_next_gap(iter);
+}
+EXPORT_SYMBOL_GPL(interval_tree_span_iter_next);
+
+/*
+ * Advance the iterator index to a specific position. The returned used/hole is
+ * updated to start at new_index. This is faster than calling
+ * interval_tree_span_iter_first() as it can avoid full searches in several
+ * cases where the iterator is already set.
+ */
+void interval_tree_span_iter_advance(struct interval_tree_span_iter *iter,
+				     struct rb_root_cached *itree,
+				     unsigned long new_index)
+{
+	if (iter->is_hole == -1)
+		return;
+
+	iter->first_index = new_index;
+	if (new_index > iter->last_index) {
+		iter->is_hole = -1;
+		return;
+	}
+
+	/* Rely on the union aliasing hole/used */
+	if (iter->start_hole <= new_index && new_index <= iter->last_hole) {
+		iter->start_hole = new_index;
+		return;
+	}
+	if (new_index == iter->last_hole + 1)
+		interval_tree_span_iter_next(iter);
+	else
+		interval_tree_span_iter_first(iter, itree, new_index,
+					      iter->last_index);
+}
+EXPORT_SYMBOL_GPL(interval_tree_span_iter_advance);
+#endif