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, 249 insertions, 0 deletions

diff --git a/block/ioprio.c b/block/ioprio.c
new file mode 100644
index 000000000..f0ee27985
--- /dev/null
+++ b/block/ioprio.c
@@ -0,0 +1,249 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * fs/ioprio.c
+ *
+ * Copyright (C) 2004 Jens Axboe <axboe@kernel.dk>
+ *
+ * Helper functions for setting/querying io priorities of processes. The
+ * system calls closely mimmick getpriority/setpriority, see the man page for
+ * those. The prio argument is a composite of prio class and prio data, where
+ * the data argument has meaning within that class. The standard scheduling
+ * classes have 8 distinct prio levels, with 0 being the highest prio and 7
+ * being the lowest.
+ *
+ * IOW, setting BE scheduling class with prio 2 is done ala:
+ *
+ * unsigned int prio = (IOPRIO_CLASS_BE << IOPRIO_CLASS_SHIFT) | 2;
+ *
+ * ioprio_set(PRIO_PROCESS, pid, prio);
+ *
+ * See also Documentation/block/ioprio.rst
+ *
+ */
+#include <linux/gfp.h>
+#include <linux/kernel.h>
+#include <linux/ioprio.h>
+#include <linux/cred.h>
+#include <linux/blkdev.h>
+#include <linux/capability.h>
+#include <linux/syscalls.h>
+#include <linux/security.h>
+#include <linux/pid_namespace.h>
+
+int ioprio_check_cap(int ioprio)
+{
+	int class = IOPRIO_PRIO_CLASS(ioprio);
+	int level = IOPRIO_PRIO_LEVEL(ioprio);
+
+	switch (class) {
+		case IOPRIO_CLASS_RT:
+			/*
+			 * Originally this only checked for CAP_SYS_ADMIN,
+			 * which was implicitly allowed for pid 0 by security
+			 * modules such as SELinux. Make sure we check
+			 * CAP_SYS_ADMIN first to avoid a denial/avc for
+			 * possibly missing CAP_SYS_NICE permission.
+			 */
+			if (!capable(CAP_SYS_ADMIN) && !capable(CAP_SYS_NICE))
+				return -EPERM;
+			break;
+		case IOPRIO_CLASS_BE:
+		case IOPRIO_CLASS_IDLE:
+			break;
+		case IOPRIO_CLASS_NONE:
+			if (level)
+				return -EINVAL;
+			break;
+		case IOPRIO_CLASS_INVALID:
+		default:
+			return -EINVAL;
+	}
+
+	return 0;
+}
+
+SYSCALL_DEFINE3(ioprio_set, int, which, int, who, int, ioprio)
+{
+	struct task_struct *p, *g;
+	struct user_struct *user;
+	struct pid *pgrp;
+	kuid_t uid;
+	int ret;
+
+	ret = ioprio_check_cap(ioprio);
+	if (ret)
+		return ret;
+
+	ret = -ESRCH;
+	rcu_read_lock();
+	switch (which) {
+		case IOPRIO_WHO_PROCESS:
+			if (!who)
+				p = current;
+			else
+				p = find_task_by_vpid(who);
+			if (p)
+				ret = set_task_ioprio(p, ioprio);
+			break;
+		case IOPRIO_WHO_PGRP:
+			if (!who)
+				pgrp = task_pgrp(current);
+			else
+				pgrp = find_vpid(who);
+
+			read_lock(&tasklist_lock);
+			do_each_pid_thread(pgrp, PIDTYPE_PGID, p) {
+				ret = set_task_ioprio(p, ioprio);
+				if (ret) {
+					read_unlock(&tasklist_lock);
+					goto out;
+				}
+			} while_each_pid_thread(pgrp, PIDTYPE_PGID, p);
+			read_unlock(&tasklist_lock);
+
+			break;
+		case IOPRIO_WHO_USER:
+			uid = make_kuid(current_user_ns(), who);
+			if (!uid_valid(uid))
+				break;
+			if (!who)
+				user = current_user();
+			else
+				user = find_user(uid);
+
+			if (!user)
+				break;
+
+			for_each_process_thread(g, p) {
+				if (!uid_eq(task_uid(p), uid) ||
+				    !task_pid_vnr(p))
+					continue;
+				ret = set_task_ioprio(p, ioprio);
+				if (ret)
+					goto free_uid;
+			}
+free_uid:
+			if (who)
+				free_uid(user);
+			break;
+		default:
+			ret = -EINVAL;
+	}
+
+out:
+	rcu_read_unlock();
+	return ret;
+}
+
+static int get_task_ioprio(struct task_struct *p)
+{
+	int ret;
+
+	ret = security_task_getioprio(p);
+	if (ret)
+		goto out;
+	task_lock(p);
+	ret = __get_task_ioprio(p);
+	task_unlock(p);
+out:
+	return ret;
+}
+
+/*
+ * Return raw IO priority value as set by userspace. We use this for
+ * ioprio_get(pid, IOPRIO_WHO_PROCESS) so that we keep historical behavior and
+ * also so that userspace can distinguish unset IO priority (which just gets
+ * overriden based on task's nice value) from IO priority set to some value.
+ */
+static int get_task_raw_ioprio(struct task_struct *p)
+{
+	int ret;
+
+	ret = security_task_getioprio(p);
+	if (ret)
+		goto out;
+	task_lock(p);
+	if (p->io_context)
+		ret = p->io_context->ioprio;
+	else
+		ret = IOPRIO_DEFAULT;
+	task_unlock(p);
+out:
+	return ret;
+}
+
+static int ioprio_best(unsigned short aprio, unsigned short bprio)
+{
+	return min(aprio, bprio);
+}
+
+SYSCALL_DEFINE2(ioprio_get, int, which, int, who)
+{
+	struct task_struct *g, *p;
+	struct user_struct *user;
+	struct pid *pgrp;
+	kuid_t uid;
+	int ret = -ESRCH;
+	int tmpio;
+
+	rcu_read_lock();
+	switch (which) {
+		case IOPRIO_WHO_PROCESS:
+			if (!who)
+				p = current;
+			else
+				p = find_task_by_vpid(who);
+			if (p)
+				ret = get_task_raw_ioprio(p);
+			break;
+		case IOPRIO_WHO_PGRP:
+			if (!who)
+				pgrp = task_pgrp(current);
+			else
+				pgrp = find_vpid(who);
+			read_lock(&tasklist_lock);
+			do_each_pid_thread(pgrp, PIDTYPE_PGID, p) {
+				tmpio = get_task_ioprio(p);
+				if (tmpio < 0)
+					continue;
+				if (ret == -ESRCH)
+					ret = tmpio;
+				else
+					ret = ioprio_best(ret, tmpio);
+			} while_each_pid_thread(pgrp, PIDTYPE_PGID, p);
+			read_unlock(&tasklist_lock);
+
+			break;
+		case IOPRIO_WHO_USER:
+			uid = make_kuid(current_user_ns(), who);
+			if (!who)
+				user = current_user();
+			else
+				user = find_user(uid);
+
+			if (!user)
+				break;
+
+			for_each_process_thread(g, p) {
+				if (!uid_eq(task_uid(p), user->uid) ||
+				    !task_pid_vnr(p))
+					continue;
+				tmpio = get_task_ioprio(p);
+				if (tmpio < 0)
+					continue;
+				if (ret == -ESRCH)
+					ret = tmpio;
+				else
+					ret = ioprio_best(ret, tmpio);
+			}
+
+			if (who)
+				free_uid(user);
+			break;
+		default:
+			ret = -EINVAL;
+	}
+
+	rcu_read_unlock();
+	return ret;
+}