// SPDX-License-Identifier: GPL-2.0
/*
 * fault injection support for nvme.
 *
 * Copyright (c) 2018, Oracle and/or its affiliates
 */

#include <linux/moduleparam.h>
#include <linux/debugfs.h>
#include "nvme.h"

static DECLARE_FAULT_ATTR(fail_default_attr);
/* optional fault injection attributes boot time option:
 * nvme_core.fail_request=<interval>,<probability>,<space>,<times>
 */
static char *fail_request;
module_param(fail_request, charp, 0000);

void nvme_fault_inject_init(struct nvme_fault_inject *fault_inj,
                            const char *dev_name)
{
        struct dentry *dir, *parent;
        struct fault_attr *attr = &fault_inj->attr;

        /* set default fault injection attribute */
        if (fail_request)
                setup_fault_attr(&fail_default_attr, fail_request);

        /* create debugfs directory and attribute */
        parent = debugfs_create_dir(dev_name, NULL);
        if (IS_ERR(parent)) {
                pr_warn("%s: failed to create debugfs directory\n", dev_name);
                return;
        }

        *attr = fail_default_attr;
        dir = fault_create_debugfs_attr("fault_inject", parent, attr);
        if (IS_ERR(dir)) {
                pr_warn("%s: failed to create debugfs attr\n", dev_name);
                debugfs_remove_recursive(parent);
                return;
        }
        fault_inj->parent = parent;

        /* create debugfs for status code and dont_retry */
        fault_inj->status = NVME_SC_INVALID_OPCODE;
        fault_inj->dont_retry = true;
        debugfs_create_x16("status", 0600, dir, &fault_inj->status);
        debugfs_create_bool("dont_retry", 0600, dir, &fault_inj->dont_retry);
}

void nvme_fault_inject_fini(struct nvme_fault_inject *fault_inject)
{
        /* remove debugfs directories */
        debugfs_remove_recursive(fault_inject->parent);
}

void nvme_should_fail(struct request *req)
{
        struct gendisk *disk = req->q->disk;
        struct nvme_fault_inject *fault_inject = NULL;
        u16 status;

        if (disk) {
                struct nvme_ns *ns = disk->private_data;

                if (ns)
                        fault_inject = &ns->fault_inject;
                else
                        WARN_ONCE(1, "No namespace found for request\n");
        } else {
                fault_inject = &nvme_req(req)->ctrl->fault_inject;
        }

        if (fault_inject && should_fail(&fault_inject->attr, 1)) {
                /* inject status code and DNR bit */
                status = fault_inject->status;
                if (fault_inject->dont_retry)
                        status |= NVME_STATUS_DNR;
                nvme_req(req)->status = status;
        }
}
EXPORT_SYMBOL_GPL(nvme_should_fail);