root/drivers/net/netdevsim/health.c
// 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 i;

        devlink_fmsg_bool_pair_put(fmsg, "test_bool", true);
        devlink_fmsg_u8_pair_put(fmsg, "test_u8", 1);
        devlink_fmsg_u32_pair_put(fmsg, "test_u32", 3);
        devlink_fmsg_u64_pair_put(fmsg, "test_u64", 4);
        devlink_fmsg_string_pair_put(fmsg, "test_string", "somestring");

        binary = kmalloc(binary_len, GFP_KERNEL | __GFP_NOWARN);
        if (!binary)
                return -ENOMEM;
        get_random_bytes(binary, binary_len);
        devlink_fmsg_binary_pair_put(fmsg, "test_binary", binary, binary_len);
        kfree(binary);

        devlink_fmsg_pair_nest_start(fmsg, "test_nest");
        devlink_fmsg_obj_nest_start(fmsg);
        devlink_fmsg_bool_pair_put(fmsg, "nested_test_bool", false);
        devlink_fmsg_u8_pair_put(fmsg, "nested_test_u8", false);
        devlink_fmsg_obj_nest_end(fmsg);
        devlink_fmsg_pair_nest_end(fmsg);
        devlink_fmsg_arr_pair_nest_end(fmsg);
        devlink_fmsg_arr_pair_nest_start(fmsg, "test_u32_array");

        for (i = 0; i < 10; i++)
                devlink_fmsg_u32_put(fmsg, i);
        devlink_fmsg_arr_pair_nest_end(fmsg);
        devlink_fmsg_arr_pair_nest_start(fmsg, "test_array_of_objects");

        for (i = 0; i < 10; i++) {
                devlink_fmsg_obj_nest_start(fmsg);
                devlink_fmsg_bool_pair_put(fmsg, "in_array_nested_test_bool",
                                           false);
                devlink_fmsg_u8_pair_put(fmsg, "in_array_nested_test_u8", i);
                devlink_fmsg_obj_nest_end(fmsg);
        }
        devlink_fmsg_arr_pair_nest_end(fmsg);

        return 0;
}

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;

        if (ctx)
                devlink_fmsg_string_pair_put(fmsg, "break_message", ctx->break_msg);

        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);

        if (health->recovered_break_msg)
                devlink_fmsg_string_pair_put(fmsg, "recovered_break_message",
                                             health->recovered_break_msg);

        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;

        if (count == 0 || count > PAGE_SIZE)
                return -EINVAL;
        break_msg = memdup_user_nul(data, count);
        if (IS_ERR(break_msg))
                return PTR_ERR(break_msg);

        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,
        .owner = THIS_MODULE,
};

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 =
                devl_health_reporter_create(devlink,
                                            &nsim_dev_empty_reporter_ops,
                                            health);
        if (IS_ERR(health->empty_reporter))
                return PTR_ERR(health->empty_reporter);

        health->dummy_reporter =
                devl_health_reporter_create(devlink,
                                            &nsim_dev_dummy_reporter_ops,
                                            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(health->ddir)) {
                err = PTR_ERR(health->ddir);
                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:
        devl_health_reporter_destroy(health->dummy_reporter);
err_empty_reporter_destroy:
        devl_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);
        devl_health_reporter_destroy(health->dummy_reporter);
        devl_health_reporter_destroy(health->empty_reporter);
}