fault_inject.c

 1// SPDX-License-Identifier: GPL-2.0
 2/*
 3 * fault injection support for nvme.
 4 *
 5 * Copyright (c) 2018, Oracle and/or its affiliates
 6 */
 7
 8#include <linux/moduleparam.h>
 9#include <linux/debugfs.h>
10#include "nvme.h"
11
12static DECLARE_FAULT_ATTR(fail_default_attr);
13/* optional fault injection attributes boot time option:
14 * nvme_core.fail_request=<interval>,<probability>,<space>,<times>
15 */
16static char *fail_request;
17module_param(fail_request, charp, 0000);
18
19void nvme_fault_inject_init(struct nvme_fault_inject *fault_inj,
20			    const char *dev_name)
21{
22	struct dentry *dir, *parent;
23	struct fault_attr *attr = &fault_inj->attr;
24
25	/* set default fault injection attribute */
26	if (fail_request)
27		setup_fault_attr(&fail_default_attr, fail_request);
28
29	/* create debugfs directory and attribute */
30	parent = debugfs_create_dir(dev_name, NULL);
31	if (IS_ERR(parent)) {
32		pr_warn("%s: failed to create debugfs directory\n", dev_name);
33		return;
34	}
35
36	*attr = fail_default_attr;
37	dir = fault_create_debugfs_attr("fault_inject", parent, attr);
38	if (IS_ERR(dir)) {
39		pr_warn("%s: failed to create debugfs attr\n", dev_name);
40		debugfs_remove_recursive(parent);
41		return;
42	}
43	fault_inj->parent = parent;
44
45	/* create debugfs for status code and dont_retry */
46	fault_inj->status = NVME_SC_INVALID_OPCODE;
47	fault_inj->dont_retry = true;
48	debugfs_create_x16("status", 0600, dir,	&fault_inj->status);
49	debugfs_create_bool("dont_retry", 0600, dir, &fault_inj->dont_retry);
50}
51
52void nvme_fault_inject_fini(struct nvme_fault_inject *fault_inject)
53{
54	/* remove debugfs directories */
55	debugfs_remove_recursive(fault_inject->parent);
56}
57
58void nvme_should_fail(struct request *req)
59{
60	struct gendisk *disk = req->q->disk;
61	struct nvme_fault_inject *fault_inject = NULL;
62	u16 status;
63
64	if (disk) {
65		struct nvme_ns *ns = disk->private_data;
66
67		if (ns)
68			fault_inject = &ns->fault_inject;
69		else
70			WARN_ONCE(1, "No namespace found for request\n");
71	} else {
72		fault_inject = &nvme_req(req)->ctrl->fault_inject;
73	}
74
75	if (fault_inject && should_fail(&fault_inject->attr, 1)) {
76		/* inject status code and DNR bit */
77		status = fault_inject->status;
78		if (fault_inject->dont_retry)
79			status |= NVME_STATUS_DNR;
80		nvme_req(req)->status =	status;
81	}
82}
83EXPORT_SYMBOL_GPL(nvme_should_fail);