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, 191 insertions, 0 deletions

diff --git a/drivers/mtd/ubi/nvmem.c b/drivers/mtd/ubi/nvmem.c
new file mode 100644
index 000000000..2dade9727
--- /dev/null
+++ b/drivers/mtd/ubi/nvmem.c
@@ -0,0 +1,191 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Copyright (c) 2023 Daniel Golle <daniel@makrotopia.org>
+ */
+
+/* UBI NVMEM provider */
+#include "ubi.h"
+#include <linux/nvmem-provider.h>
+
+/* List of all NVMEM devices */
+static LIST_HEAD(nvmem_devices);
+static DEFINE_MUTEX(devices_mutex);
+
+struct ubi_nvmem {
+	struct nvmem_device *nvmem;
+	int ubi_num;
+	int vol_id;
+	int usable_leb_size;
+	struct list_head list;
+};
+
+static int ubi_nvmem_reg_read(void *priv, unsigned int from,
+			      void *val, size_t bytes)
+{
+	size_t to_read, bytes_left = bytes;
+	struct ubi_nvmem *unv = priv;
+	struct ubi_volume_desc *desc;
+	uint32_t offs;
+	uint32_t lnum;
+	int err = 0;
+
+	desc = ubi_open_volume(unv->ubi_num, unv->vol_id, UBI_READONLY);
+	if (IS_ERR(desc))
+		return PTR_ERR(desc);
+
+	offs = from % unv->usable_leb_size;
+	lnum = from / unv->usable_leb_size;
+	while (bytes_left) {
+		to_read = unv->usable_leb_size - offs;
+
+		if (to_read > bytes_left)
+			to_read = bytes_left;
+
+		err = ubi_read(desc, lnum, val, offs, to_read);
+		if (err)
+			break;
+
+		lnum += 1;
+		offs = 0;
+		bytes_left -= to_read;
+		val += to_read;
+	}
+	ubi_close_volume(desc);
+
+	if (err)
+		return err;
+
+	return 0;
+}
+
+static int ubi_nvmem_add(struct ubi_volume_info *vi)
+{
+	struct device_node *np = dev_of_node(vi->dev);
+	struct nvmem_config config = {};
+	struct ubi_nvmem *unv;
+	int ret;
+
+	if (!np)
+		return 0;
+
+	if (!of_get_child_by_name(np, "nvmem-layout"))
+		return 0;
+
+	if (WARN_ON_ONCE(vi->usable_leb_size <= 0) ||
+	    WARN_ON_ONCE(vi->size <= 0))
+		return -EINVAL;
+
+	unv = kzalloc_obj(struct ubi_nvmem);
+	if (!unv)
+		return -ENOMEM;
+
+	config.id = NVMEM_DEVID_NONE;
+	config.dev = vi->dev;
+	config.name = dev_name(vi->dev);
+	config.owner = THIS_MODULE;
+	config.priv = unv;
+	config.reg_read = ubi_nvmem_reg_read;
+	config.size = vi->usable_leb_size * vi->size;
+	config.word_size = 1;
+	config.stride = 1;
+	config.read_only = true;
+	config.root_only = true;
+	config.ignore_wp = true;
+	config.of_node = np;
+
+	unv->ubi_num = vi->ubi_num;
+	unv->vol_id = vi->vol_id;
+	unv->usable_leb_size = vi->usable_leb_size;
+	unv->nvmem = nvmem_register(&config);
+	if (IS_ERR(unv->nvmem)) {
+		ret = dev_err_probe(vi->dev, PTR_ERR(unv->nvmem),
+				    "Failed to register NVMEM device\n");
+		kfree(unv);
+		return ret;
+	}
+
+	mutex_lock(&devices_mutex);
+	list_add_tail(&unv->list, &nvmem_devices);
+	mutex_unlock(&devices_mutex);
+
+	return 0;
+}
+
+static void ubi_nvmem_remove(struct ubi_volume_info *vi)
+{
+	struct ubi_nvmem *unv_c, *unv = NULL;
+
+	mutex_lock(&devices_mutex);
+	list_for_each_entry(unv_c, &nvmem_devices, list)
+		if (unv_c->ubi_num == vi->ubi_num && unv_c->vol_id == vi->vol_id) {
+			unv = unv_c;
+			break;
+		}
+
+	if (!unv) {
+		mutex_unlock(&devices_mutex);
+		return;
+	}
+
+	list_del(&unv->list);
+	mutex_unlock(&devices_mutex);
+	nvmem_unregister(unv->nvmem);
+	kfree(unv);
+}
+
+/**
+ * nvmem_notify - UBI notification handler.
+ * @nb: registered notifier block
+ * @l: notification type
+ * @ns_ptr: pointer to the &struct ubi_notification object
+ */
+static int nvmem_notify(struct notifier_block *nb, unsigned long l,
+			 void *ns_ptr)
+{
+	struct ubi_notification *nt = ns_ptr;
+
+	switch (l) {
+	case UBI_VOLUME_RESIZED:
+		ubi_nvmem_remove(&nt->vi);
+		fallthrough;
+	case UBI_VOLUME_ADDED:
+		ubi_nvmem_add(&nt->vi);
+		break;
+	case UBI_VOLUME_SHUTDOWN:
+		ubi_nvmem_remove(&nt->vi);
+		break;
+	default:
+		break;
+	}
+	return NOTIFY_OK;
+}
+
+static struct notifier_block nvmem_notifier = {
+	.notifier_call = nvmem_notify,
+};
+
+static int __init ubi_nvmem_init(void)
+{
+	return ubi_register_volume_notifier(&nvmem_notifier, 0);
+}
+
+static void __exit ubi_nvmem_exit(void)
+{
+	struct ubi_nvmem *unv, *tmp;
+
+	mutex_lock(&devices_mutex);
+	list_for_each_entry_safe(unv, tmp, &nvmem_devices, list) {
+		nvmem_unregister(unv->nvmem);
+		list_del(&unv->list);
+		kfree(unv);
+	}
+	mutex_unlock(&devices_mutex);
+
+	ubi_unregister_volume_notifier(&nvmem_notifier);
+}
+
+module_init(ubi_nvmem_init);
+module_exit(ubi_nvmem_exit);
+MODULE_DESCRIPTION("NVMEM layer over UBI volumes");
+MODULE_AUTHOR("Daniel Golle");
+MODULE_LICENSE("GPL");