netdevsim: implement couple of testing devlink health reporters

Implement "empty" and "dummy" reporters. The first one is really simple
and does nothing. The other one has debugfs files to trigger breakage
and it is able to do recovery. The ops also implement dummy fmsg
content.

Signed-off-by: Jiri Pirko <jiri@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/netdevsim/Makefile

@@ -3,7 +3,7 @@
 obj-$(CONFIG_NETDEVSIM) += netdevsim.o
 
 netdevsim-objs := \
-	netdev.o dev.o fib.o bus.o
+	netdev.o dev.o fib.o bus.o health.o
 
 ifeq ($(CONFIG_BPF_SYSCALL),y)
 netdevsim-objs += \

drivers/net/netdevsim/dev.c

@@ -730,12 +730,18 @@ static int nsim_dev_reload_create(struct nsim_dev *nsim_dev,
 	if (err)
 		goto err_dummy_region_exit;
 
-	err = nsim_dev_port_add_all(nsim_dev, nsim_bus_dev->port_count);
+	err = nsim_dev_health_init(nsim_dev, devlink);
 	if (err)
 		goto err_traps_exit;
 
+	err = nsim_dev_port_add_all(nsim_dev, nsim_bus_dev->port_count);
+	if (err)
+		goto err_health_exit;
+
 	return 0;
 
+err_health_exit:
+	nsim_dev_health_exit(nsim_dev);
 err_traps_exit:
 	nsim_dev_traps_exit(devlink);
 err_dummy_region_exit:
@@ -797,10 +803,14 @@ static struct nsim_dev *nsim_dev_create(struct nsim_bus_dev *nsim_bus_dev)
 	if (err)
 		goto err_traps_exit;
 
-	err = nsim_bpf_dev_init(nsim_dev);
+	err = nsim_dev_health_init(nsim_dev, devlink);
 	if (err)
 		goto err_debugfs_exit;
 
+	err = nsim_bpf_dev_init(nsim_dev);
+	if (err)
+		goto err_health_exit;
+
 	err = nsim_dev_port_add_all(nsim_dev, nsim_bus_dev->port_count);
 	if (err)
 		goto err_bpf_dev_exit;
@@ -810,6 +820,8 @@ static struct nsim_dev *nsim_dev_create(struct nsim_bus_dev *nsim_bus_dev)
 
 err_bpf_dev_exit:
 	nsim_bpf_dev_exit(nsim_dev);
+err_health_exit:
+	nsim_dev_health_exit(nsim_dev);
 err_debugfs_exit:
 	nsim_dev_debugfs_exit(nsim_dev);
 err_traps_exit:
@@ -837,6 +849,7 @@ static void nsim_dev_reload_destroy(struct nsim_dev *nsim_dev)
 	if (devlink_is_reload_failed(devlink))
 		return;
 	nsim_dev_port_del_all(nsim_dev);
+	nsim_dev_health_exit(nsim_dev);
 	nsim_dev_traps_exit(devlink);
 	nsim_dev_dummy_region_exit(nsim_dev);
 	mutex_destroy(&nsim_dev->port_list_lock);

drivers/net/netdevsim/health.c

@@ -0,0 +1,325 @@
+// SPDX-License-Identifier: GPL-2.0
+/* Copyright (c) 2019 Mellanox Technologies. All rights reserved */
+
+#include <linux/debugfs.h>
+#include <linux/err.h>
+#include <linux/kernel.h>
+#include <linux/slab.h>
+
+#include "netdevsim.h"
+
+static int
+nsim_dev_empty_reporter_dump(struct devlink_health_reporter *reporter,
+			     struct devlink_fmsg *fmsg, void *priv_ctx,
+			     struct netlink_ext_ack *extack)
+{
+	return 0;
+}
+
+static int
+nsim_dev_empty_reporter_diagnose(struct devlink_health_reporter *reporter,
+				 struct devlink_fmsg *fmsg,
+				 struct netlink_ext_ack *extack)
+{
+	return 0;
+}
+
+static const
+struct devlink_health_reporter_ops nsim_dev_empty_reporter_ops = {
+	.name = "empty",
+	.dump = nsim_dev_empty_reporter_dump,
+	.diagnose = nsim_dev_empty_reporter_diagnose,
+};
+
+struct nsim_dev_dummy_reporter_ctx {
+	char *break_msg;
+};
+
+static int
+nsim_dev_dummy_reporter_recover(struct devlink_health_reporter *reporter,
+				void *priv_ctx,
+				struct netlink_ext_ack *extack)
+{
+	struct nsim_dev_health *health = devlink_health_reporter_priv(reporter);
+	struct nsim_dev_dummy_reporter_ctx *ctx = priv_ctx;
+
+	if (health->fail_recover) {
+		/* For testing purposes, user set debugfs fail_recover
+		 * value to true. Fail right away.
+		 */
+		NL_SET_ERR_MSG_MOD(extack, "User setup the recover to fail for testing purposes");
+		return -EINVAL;
+	}
+	if (ctx) {
+		kfree(health->recovered_break_msg);
+		health->recovered_break_msg = kstrdup(ctx->break_msg,
+						      GFP_KERNEL);
+		if (!health->recovered_break_msg)
+			return -ENOMEM;
+	}
+	return 0;
+}
+
+static int nsim_dev_dummy_fmsg_put(struct devlink_fmsg *fmsg, u32 binary_len)
+{
+	char *binary;
+	int err;
+	int i;
+
+	err = devlink_fmsg_bool_pair_put(fmsg, "test_bool", true);
+	if (err)
+		return err;
+	err = devlink_fmsg_u8_pair_put(fmsg, "test_u8", 1);
+	if (err)
+		return err;
+	err = devlink_fmsg_u32_pair_put(fmsg, "test_u32", 3);
+	if (err)
+		return err;
+	err = devlink_fmsg_u64_pair_put(fmsg, "test_u64", 4);
+	if (err)
+		return err;
+	err = devlink_fmsg_string_pair_put(fmsg, "test_string", "somestring");
+	if (err)
+		return err;
+
+	err = devlink_fmsg_arr_pair_nest_start(fmsg, "test_binary");
+	if (err)
+		return err;
+	binary = kmalloc(binary_len, GFP_KERNEL);
+	if (!binary)
+		return -ENOMEM;
+	get_random_bytes(binary, binary_len);
+	err = devlink_fmsg_binary_put(fmsg, binary, binary_len);
+	kfree(binary);
+	if (err)
+		return err;
+	err = devlink_fmsg_arr_pair_nest_end(fmsg);
+	if (err)
+		return err;
+
+	err = devlink_fmsg_pair_nest_start(fmsg, "test_nest");
+	if (err)
+		return err;
+	err = devlink_fmsg_obj_nest_start(fmsg);
+	if (err)
+		return err;
+	err = devlink_fmsg_bool_pair_put(fmsg, "nested_test_bool", false);
+	if (err)
+		return err;
+	err = devlink_fmsg_u8_pair_put(fmsg, "nested_test_u8", false);
+	if (err)
+		return err;
+	err = devlink_fmsg_obj_nest_end(fmsg);
+	if (err)
+		return err;
+	err = devlink_fmsg_pair_nest_end(fmsg);
+	if (err)
+		return err;
+
+	err = devlink_fmsg_arr_pair_nest_start(fmsg, "test_bool_array");
+	if (err)
+		return err;
+	for (i = 0; i < 10; i++) {
+		err = devlink_fmsg_bool_put(fmsg, true);
+		if (err)
+			return err;
+	}
+	err = devlink_fmsg_arr_pair_nest_end(fmsg);
+	if (err)
+		return err;
+
+	err = devlink_fmsg_arr_pair_nest_start(fmsg, "test_u8_array");
+	if (err)
+		return err;
+	for (i = 0; i < 10; i++) {
+		err = devlink_fmsg_u8_put(fmsg, i);
+		if (err)
+			return err;
+	}
+	err = devlink_fmsg_arr_pair_nest_end(fmsg);
+	if (err)
+		return err;
+
+	err = devlink_fmsg_arr_pair_nest_start(fmsg, "test_u32_array");
+	if (err)
+		return err;
+	for (i = 0; i < 10; i++) {
+		err = devlink_fmsg_u32_put(fmsg, i);
+		if (err)
+			return err;
+	}
+	err = devlink_fmsg_arr_pair_nest_end(fmsg);
+	if (err)
+		return err;
+
+	err = devlink_fmsg_arr_pair_nest_start(fmsg, "test_u64_array");
+	if (err)
+		return err;
+	for (i = 0; i < 10; i++) {
+		err = devlink_fmsg_u64_put(fmsg, i);
+		if (err)
+			return err;
+	}
+	err = devlink_fmsg_arr_pair_nest_end(fmsg);
+	if (err)
+		return err;
+
+	err = devlink_fmsg_arr_pair_nest_start(fmsg, "test_array_of_objects");
+	if (err)
+		return err;
+	for (i = 0; i < 10; i++) {
+		err = devlink_fmsg_obj_nest_start(fmsg);
+		if (err)
+			return err;
+		err = devlink_fmsg_bool_pair_put(fmsg,
+						 "in_array_nested_test_bool",
+						 false);
+		if (err)
+			return err;
+		err = devlink_fmsg_u8_pair_put(fmsg,
+					       "in_array_nested_test_u8",
+					       i);
+		if (err)
+			return err;
+		err = devlink_fmsg_obj_nest_end(fmsg);
+		if (err)
+			return err;
+	}
+	return devlink_fmsg_arr_pair_nest_end(fmsg);
+}
+
+static int
+nsim_dev_dummy_reporter_dump(struct devlink_health_reporter *reporter,
+			     struct devlink_fmsg *fmsg, void *priv_ctx,
+			     struct netlink_ext_ack *extack)
+{
+	struct nsim_dev_health *health = devlink_health_reporter_priv(reporter);
+	struct nsim_dev_dummy_reporter_ctx *ctx = priv_ctx;
+	int err;
+
+	if (ctx) {
+		err = devlink_fmsg_string_pair_put(fmsg, "break_message",
+						   ctx->break_msg);
+		if (err)
+			return err;
+	}
+	return nsim_dev_dummy_fmsg_put(fmsg, health->binary_len);
+}
+
+static int
+nsim_dev_dummy_reporter_diagnose(struct devlink_health_reporter *reporter,
+				 struct devlink_fmsg *fmsg,
+				 struct netlink_ext_ack *extack)
+{
+	struct nsim_dev_health *health = devlink_health_reporter_priv(reporter);
+	int err;
+
+	if (health->recovered_break_msg) {
+		err = devlink_fmsg_string_pair_put(fmsg,
+						   "recovered_break_message",
+						   health->recovered_break_msg);
+		if (err)
+			return err;
+	}
+	return nsim_dev_dummy_fmsg_put(fmsg, health->binary_len);
+}
+
+static const
+struct devlink_health_reporter_ops nsim_dev_dummy_reporter_ops = {
+	.name = "dummy",
+	.recover = nsim_dev_dummy_reporter_recover,
+	.dump = nsim_dev_dummy_reporter_dump,
+	.diagnose = nsim_dev_dummy_reporter_diagnose,
+};
+
+static ssize_t nsim_dev_health_break_write(struct file *file,
+					   const char __user *data,
+					   size_t count, loff_t *ppos)
+{
+	struct nsim_dev_health *health = file->private_data;
+	struct nsim_dev_dummy_reporter_ctx ctx;
+	char *break_msg;
+	int err;
+
+	break_msg = kmalloc(count + 1, GFP_KERNEL);
+	if (!break_msg)
+		return -ENOMEM;
+
+	if (copy_from_user(break_msg, data, count)) {
+		err = -EFAULT;
+		goto out;
+	}
+	break_msg[count] = '\0';
+	if (break_msg[count - 1] == '\n')
+		break_msg[count - 1] = '\0';
+
+	ctx.break_msg = break_msg;
+	err = devlink_health_report(health->dummy_reporter, break_msg, &ctx);
+	if (err)
+		goto out;
+
+out:
+	kfree(break_msg);
+	return err ?: count;
+}
+
+static const struct file_operations nsim_dev_health_break_fops = {
+	.open = simple_open,
+	.write = nsim_dev_health_break_write,
+	.llseek = generic_file_llseek,
+};
+
+int nsim_dev_health_init(struct nsim_dev *nsim_dev, struct devlink *devlink)
+{
+	struct nsim_dev_health *health = &nsim_dev->health;
+	int err;
+
+	health->empty_reporter =
+		devlink_health_reporter_create(devlink,
+					       &nsim_dev_empty_reporter_ops,
+					       0, false, health);
+	if (IS_ERR(health->empty_reporter))
+		return PTR_ERR(health->empty_reporter);
+
+	health->dummy_reporter =
+		devlink_health_reporter_create(devlink,
+					       &nsim_dev_dummy_reporter_ops,
+					       0, false, health);
+	if (IS_ERR(health->dummy_reporter)) {
+		err = PTR_ERR(health->dummy_reporter);
+		goto err_empty_reporter_destroy;
+	}
+
+	health->ddir = debugfs_create_dir("health", nsim_dev->ddir);
+	if (IS_ERR_OR_NULL(health->ddir)) {
+		err = PTR_ERR_OR_ZERO(health->ddir) ?: -EINVAL;
+		goto err_dummy_reporter_destroy;
+	}
+
+	health->recovered_break_msg = NULL;
+	debugfs_create_file("break_health", 0200, health->ddir, health,
+			    &nsim_dev_health_break_fops);
+	health->binary_len = 16;
+	debugfs_create_u32("binary_len", 0600, health->ddir,
+			   &health->binary_len);
+	health->fail_recover = false;
+	debugfs_create_bool("fail_recover", 0600, health->ddir,
+			    &health->fail_recover);
+	return 0;
+
+err_dummy_reporter_destroy:
+	devlink_health_reporter_destroy(health->dummy_reporter);
+err_empty_reporter_destroy:
+	devlink_health_reporter_destroy(health->empty_reporter);
+	return err;
+}
+
+void nsim_dev_health_exit(struct nsim_dev *nsim_dev)
+{
+	struct nsim_dev_health *health = &nsim_dev->health;
+
+	debugfs_remove_recursive(health->ddir);
+	kfree(health->recovered_break_msg);
+	devlink_health_reporter_destroy(health->dummy_reporter);
+	devlink_health_reporter_destroy(health->empty_reporter);
+}