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, 97 insertions, 0 deletions

diff --git a/fs/fs_pin.c b/fs/fs_pin.c
new file mode 100644
index 000000000..47ef3c71c
--- /dev/null
+++ b/fs/fs_pin.c
@@ -0,0 +1,97 @@
+// SPDX-License-Identifier: GPL-2.0
+#include <linux/fs.h>
+#include <linux/sched.h>
+#include <linux/slab.h>
+#include "internal.h"
+#include "mount.h"
+
+static DEFINE_SPINLOCK(pin_lock);
+
+void pin_remove(struct fs_pin *pin)
+{
+	spin_lock(&pin_lock);
+	hlist_del_init(&pin->m_list);
+	hlist_del_init(&pin->s_list);
+	spin_unlock(&pin_lock);
+	spin_lock_irq(&pin->wait.lock);
+	pin->done = 1;
+	wake_up_locked(&pin->wait);
+	spin_unlock_irq(&pin->wait.lock);
+}
+
+void pin_insert(struct fs_pin *pin, struct vfsmount *m)
+{
+	spin_lock(&pin_lock);
+	hlist_add_head(&pin->s_list, &m->mnt_sb->s_pins);
+	hlist_add_head(&pin->m_list, &real_mount(m)->mnt_pins);
+	spin_unlock(&pin_lock);
+}
+
+void pin_kill(struct fs_pin *p)
+{
+	wait_queue_entry_t wait;
+
+	if (!p) {
+		rcu_read_unlock();
+		return;
+	}
+	init_wait(&wait);
+	spin_lock_irq(&p->wait.lock);
+	if (likely(!p->done)) {
+		p->done = -1;
+		spin_unlock_irq(&p->wait.lock);
+		rcu_read_unlock();
+		p->kill(p);
+		return;
+	}
+	if (p->done > 0) {
+		spin_unlock_irq(&p->wait.lock);
+		rcu_read_unlock();
+		return;
+	}
+	__add_wait_queue(&p->wait, &wait);
+	while (1) {
+		set_current_state(TASK_UNINTERRUPTIBLE);
+		spin_unlock_irq(&p->wait.lock);
+		rcu_read_unlock();
+		schedule();
+		rcu_read_lock();
+		if (likely(list_empty(&wait.entry)))
+			break;
+		/* OK, we know p couldn't have been freed yet */
+		spin_lock_irq(&p->wait.lock);
+		if (p->done > 0) {
+			spin_unlock_irq(&p->wait.lock);
+			break;
+		}
+	}
+	rcu_read_unlock();
+}
+
+void mnt_pin_kill(struct mount *m)
+{
+	while (1) {
+		struct hlist_node *p;
+		rcu_read_lock();
+		p = READ_ONCE(m->mnt_pins.first);
+		if (!p) {
+			rcu_read_unlock();
+			break;
+		}
+		pin_kill(hlist_entry(p, struct fs_pin, m_list));
+	}
+}
+
+void group_pin_kill(struct hlist_head *p)
+{
+	while (1) {
+		struct hlist_node *q;
+		rcu_read_lock();
+		q = READ_ONCE(p->first);
+		if (!q) {
+			rcu_read_unlock();
+			break;
+		}
+		pin_kill(hlist_entry(q, struct fs_pin, s_list));
+	}
+}