[PATCH v3 0/2] nvme: Add fault injection feature

[PATCH v3 0/2] nvme: Add fault injection feature

[Thomas Tai]

Linux's fault injection framework provides a systematic way to support
error injection via debugfs in the /sys/kernel/debug directory. This
patch uses the framework to add error injection to NVMe driver. 

Change log since last version:
V2:
- add user changable status and no_retry debugfs attribute
- add document to show how to use nvme fault injection

V1:
- move error injection point into nvme_end_request()
- Add expected result in the commit log

Thank you,
Thomas

[PATCH v3 1/2] nvme: Add fault injection feature

[Thomas Tai]

Linux's fault injection framework provides a systematic way to support
error injection via debugfs in the /sys/kernel/debug directory. This
patch uses the framework to add error injection to NVMe driver. The
fault injection source code is stored in a separate file and only linked
if CONFIG_FAULT_INJECTION_DEBUG_FS kernel config is selected.

Once the error injection is enabled, NVME_SC_INVALID_OPCODE with no
retry will be injected into the nvme_end_request. Users can change
the default status code and no retry flag via debufs. Following example
shows how to enable and inject an error. For more examples, refer to
Documentation/fault-injection/nvme-fault-injection.txt

How to enable nvme fault injection:

First, enable CONFIG_FAULT_INJECTION_DEBUG_FS kernel config,
recompile the kernel. After booting up the kernel, do the
following.

How to inject an error:

mount /dev/nvme0n1 /mnt
echo 1 > /sys/kernel/debug/nvme0n1/fault_inject/times
echo 100 > /sys/kernel/debug/nvme0n1/fault_inject/probability
cp a.file /mnt

Expected Result:

cp: cannot stat ?/mnt/a.file?: Input/output error

Message from dmesg:

FAULT_INJECTION: forcing a failure.
name fault_inject, interval 1, probability 100, space 0, times 1
CPU: 0 PID: 0 Comm: swapper/0 Not tainted 4.15.0-rc8+ #2
Hardware name: innotek GmbH VirtualBox/VirtualBox,
BIOS VirtualBox 12/01/2006
Call Trace:
  <IRQ>
  dump_stack+0x5c/0x7d
  should_fail+0x148/0x170
  nvme_should_fail+0x2f/0x50 [nvme_core]
  nvme_process_cq+0xe7/0x1d0 [nvme]
  nvme_irq+0x1e/0x40 [nvme]
  __handle_irq_event_percpu+0x3a/0x190
  handle_irq_event_percpu+0x30/0x70
  handle_irq_event+0x36/0x60
  handle_fasteoi_irq+0x78/0x120
  handle_irq+0xa7/0x130
  ? tick_irq_enter+0xa8/0xc0
  do_IRQ+0x43/0xc0
  common_interrupt+0xa2/0xa2
  </IRQ>
RIP: 0010:native_safe_halt+0x2/0x10
RSP: 0018:ffffffff82003e90 EFLAGS: 00000246 ORIG_RAX: ffffffffffffffdd
RAX: ffffffff817a10c0 RBX: ffffffff82012480 RCX: 0000000000000000
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
RBP: 0000000000000000 R08: 000000008e38ce64 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000000 R12: ffffffff82012480
R13: ffffffff82012480 R14: 0000000000000000 R15: 0000000000000000
  ? __sched_text_end+0x4/0x4
  default_idle+0x18/0xf0
  do_idle+0x150/0x1d0
  cpu_startup_entry+0x6f/0x80
  start_kernel+0x4c4/0x4e4
  ? set_init_arg+0x55/0x55
  secondary_startup_64+0xa5/0xb0
  print_req_error: I/O error, dev nvme0n1, sector 9240
EXT4-fs error (device nvme0n1): ext4_find_entry:1436:
inode #2: comm cp: reading directory lblock 0

Signed-off-by: Thomas Tai <thomas.tai at oracle.com>
Reviewed-by: Eric Saint-Etienne <eric.saint.etienne at oracle.com>
Signed-off-by: Karl Volz <karl.volz at oracle.com>
---
 drivers/nvme/host/Makefile       |  1 +
 drivers/nvme/host/core.c         |  2 +
 drivers/nvme/host/fault_inject.c | 79 ++++++++++++++++++++++++++++++++++++++++
 drivers/nvme/host/nvme.h         | 27 ++++++++++++++
 4 files changed, 109 insertions(+)
 create mode 100644 drivers/nvme/host/fault_inject.c

diff --git a/drivers/nvme/host/Makefile b/drivers/nvme/host/Makefile
index a25fd43..d38131e 100644
--- a/drivers/nvme/host/Makefile
+++ b/drivers/nvme/host/Makefile
@@ -8,6 +8,7 @@ obj-$(CONFIG_NVME_FC)			+= nvme-fc.o
 nvme-core-y				:= core.o
 nvme-core-$(CONFIG_NVME_MULTIPATH)	+= multipath.o
 nvme-core-$(CONFIG_NVM)			+= lightnvm.o
+nvme-core-$(CONFIG_FAULT_INJECTION_DEBUG_FS)	+= fault_inject.o
 
 nvme-y					+= pci.o
 
diff --git a/drivers/nvme/host/core.c b/drivers/nvme/host/core.c
index 839650e..49fa6da 100644
--- a/drivers/nvme/host/core.c
+++ b/drivers/nvme/host/core.c
@@ -2951,6 +2951,7 @@ static void nvme_alloc_ns(struct nvme_ctrl *ctrl, unsigned nsid)
 	if (new)
 		nvme_mpath_add_disk(ns->head);
 	nvme_mpath_add_disk_links(ns);
+	nvme_fault_inject_init(ns);
 	return;
  out_unlink_ns:
 	mutex_lock(&ctrl->subsys->lock);
@@ -2969,6 +2970,7 @@ static void nvme_ns_remove(struct nvme_ns *ns)
 	if (test_and_set_bit(NVME_NS_REMOVING, &ns->flags))
 		return;
 
+	nvme_fault_inject_fini(ns);
 	if (ns->disk && ns->disk->flags & GENHD_FL_UP) {
 		nvme_mpath_remove_disk_links(ns);
 		sysfs_remove_group(&disk_to_dev(ns->disk)->kobj,
diff --git a/drivers/nvme/host/fault_inject.c b/drivers/nvme/host/fault_inject.c
new file mode 100644
index 0000000..0263226
--- /dev/null
+++ b/drivers/nvme/host/fault_inject.c
@@ -0,0 +1,79 @@
+/*
+ * fault injection support for nvme.
+ *
+ * Copyright (c) 2018, Oracle and/or its affiliates
+ *
+ */
+
+#include <linux/moduleparam.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_ns *ns)
+{
+	struct dentry *dir, *parent;
+	char *name = ns->disk->disk_name;
+	struct nvme_fault_inject *fault_inj = &ns->fault_inject;
+	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(name, NULL);
+	if (!parent) {
+		pr_warn("%s: failed to create debugfs directory\n", 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", name);
+		debugfs_remove_recursive(parent);
+		return;
+	}
+	ns->fault_inject.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_ns *ns)
+{
+	/* remove debugfs directories */
+	debugfs_remove_recursive(ns->fault_inject.parent);
+}
+
+void nvme_should_fail(struct request *req)
+{
+	struct gendisk *disk = req->rq_disk;
+	struct nvme_ns *ns = NULL;
+	u16 status;
+
+	/*
+	 * make sure this request is coming from a valid namespace
+	 */
+	if (!disk)
+		return;
+
+	ns = disk->private_data;
+	if (ns && should_fail(&ns->fault_inject.attr, 1)) {
+		/* inject status code and DNR bit */
+		status = ns->fault_inject.status;
+		if (ns->fault_inject.dont_retry)
+			status |= NVME_SC_DNR;
+		nvme_req(req)->status =	status;
+	}
+}
+EXPORT_SYMBOL_GPL(nvme_should_fail);
diff --git a/drivers/nvme/host/nvme.h b/drivers/nvme/host/nvme.h
index a00eabd..456a7a8 100644
--- a/drivers/nvme/host/nvme.h
+++ b/drivers/nvme/host/nvme.h
@@ -21,6 +21,7 @@
 #include <linux/blk-mq.h>
 #include <linux/lightnvm.h>
 #include <linux/sed-opal.h>
+#include <linux/fault-inject.h>
 
 extern unsigned int nvme_io_timeout;
 #define NVME_IO_TIMEOUT	(nvme_io_timeout * HZ)
@@ -257,6 +258,15 @@ struct nvme_ns_head {
 	int			instance;
 };
 
+#ifdef CONFIG_FAULT_INJECTION_DEBUG_FS
+struct nvme_fault_inject {
+	struct fault_attr attr;
+	struct dentry *parent;
+	bool dont_retry;	/* DNR, do not retry */
+	u16 status;		/* status code */
+};
+#endif
+
 struct nvme_ns {
 	struct list_head list;
 
@@ -278,6 +288,11 @@ struct nvme_ns {
 #define NVME_NS_REMOVING 0
 #define NVME_NS_DEAD     1
 	u16 noiob;
+
+#ifdef CONFIG_FAULT_INJECTION_DEBUG_FS
+	struct nvme_fault_inject fault_inject;
+#endif
+
 };
 
 struct nvme_ctrl_ops {
@@ -296,6 +311,16 @@ struct nvme_ctrl_ops {
 	int (*reinit_request)(void *data, struct request *rq);
 };
 
+#ifdef CONFIG_FAULT_INJECTION_DEBUG_FS
+void nvme_fault_inject_init(struct nvme_ns *ns);
+void nvme_fault_inject_fini(struct nvme_ns *ns);
+void nvme_should_fail(struct request *req);
+#else
+static inline void nvme_fault_inject_init(struct nvme_ns *ns) {}
+static inline void nvme_fault_inject_fini(struct nvme_ns *ns) {}
+static inline void nvme_should_fail(struct request *req) {}
+#endif
+
 static inline bool nvme_ctrl_ready(struct nvme_ctrl *ctrl)
 {
 	u32 val = 0;
@@ -332,6 +357,8 @@ static inline void nvme_end_request(struct request *req, __le16 status,
 
 	rq->status = le16_to_cpu(status) >> 1;
 	rq->result = result;
+	/* inject error when permitted by fault injection framework */
+	nvme_should_fail(req);
 	blk_mq_complete_request(req);
 }
 
-- 
1.8.3.1

[PATCH v3 2/2] Documentation: nvme: Documentation for nvme fault injection

[Thomas Tai]

Add examples to show how to use nvme fault injection.

Signed-off-by: Thomas Tai <thomas.tai at oracle.com>
Reviewed-by: Eric Saint-Etienne <eric.saint.etienne at oracle.com>
Signed-off-by: Karl Volz <karl.volz at oracle.com>
---
 Documentation/fault-injection/fault-injection.txt  |   5 +
 .../fault-injection/nvme-fault-injection.txt       | 116 +++++++++++++++++++++
 2 files changed, 121 insertions(+)
 create mode 100644 Documentation/fault-injection/nvme-fault-injection.txt

diff --git a/Documentation/fault-injection/fault-injection.txt b/Documentation/fault-injection/fault-injection.txt
index 918972b..db547c2 100644
--- a/Documentation/fault-injection/fault-injection.txt
+++ b/Documentation/fault-injection/fault-injection.txt
@@ -30,6 +30,11 @@ o fail_mmc_request
   injects MMC data errors on devices permitted by setting
   debugfs entries under /sys/kernel/debug/mmc0/fail_mmc_request
 
+o NVMe fault injection
+
+  inject NVMe NVME_SC_INVALID_OPCODE with no retry on devices permitted
+  by setting debugfs entries under /sys/kernel/debug/nvme*/fault_inject
+
 Configure fault-injection capabilities behavior
 -----------------------------------------------
 
diff --git a/Documentation/fault-injection/nvme-fault-injection.txt b/Documentation/fault-injection/nvme-fault-injection.txt
new file mode 100644
index 0000000..e37b9c7
--- /dev/null
+++ b/Documentation/fault-injection/nvme-fault-injection.txt
@@ -0,0 +1,116 @@
+NVMe Fault Injection
+====================
+Linux's fault injection framework provides a systematic way to support
+error injection via debugfs in the /sys/kernel/debug directory. When
+enabled, the default NVME_SC_INVALID_OPCODE with no retry will be
+injected into the nvme_end_request. Users can change the default status
+code and no retry flag via the debugfs. The list of Generic Command
+Status can be found in include/linux/nvme.h
+
+Following examples show how to inject an error into the nvme.
+
+First, enable CONFIG_FAULT_INJECTION_DEBUG_FS kernel config,
+recompile the kernel. After booting up the kernel, do the
+following.
+
+Example 1: Inject default status code with no retry
+---------------------------------------------------
+
+mount /dev/nvme0n1 /mnt
+echo 1 > /sys/kernel/debug/nvme0n1/fault_inject/times
+echo 100 > /sys/kernel/debug/nvme0n1/fault_inject/probability
+cp a.file /mnt
+
+Expected Result:
+
+cp: cannot stat ?/mnt/a.file?: Input/output error
+
+Message from dmesg:
+
+FAULT_INJECTION: forcing a failure.
+name fault_inject, interval 1, probability 100, space 0, times 1
+CPU: 0 PID: 0 Comm: swapper/0 Not tainted 4.15.0-rc8+ #2
+Hardware name: innotek GmbH VirtualBox/VirtualBox,
+BIOS VirtualBox 12/01/2006
+Call Trace:
+  <IRQ>
+  dump_stack+0x5c/0x7d
+  should_fail+0x148/0x170
+  nvme_should_fail+0x2f/0x50 [nvme_core]
+  nvme_process_cq+0xe7/0x1d0 [nvme]
+  nvme_irq+0x1e/0x40 [nvme]
+  __handle_irq_event_percpu+0x3a/0x190
+  handle_irq_event_percpu+0x30/0x70
+  handle_irq_event+0x36/0x60
+  handle_fasteoi_irq+0x78/0x120
+  handle_irq+0xa7/0x130
+  ? tick_irq_enter+0xa8/0xc0
+  do_IRQ+0x43/0xc0
+  common_interrupt+0xa2/0xa2
+  </IRQ>
+RIP: 0010:native_safe_halt+0x2/0x10
+RSP: 0018:ffffffff82003e90 EFLAGS: 00000246 ORIG_RAX: ffffffffffffffdd
+RAX: ffffffff817a10c0 RBX: ffffffff82012480 RCX: 0000000000000000
+RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
+RBP: 0000000000000000 R08: 000000008e38ce64 R09: 0000000000000000
+R10: 0000000000000000 R11: 0000000000000000 R12: ffffffff82012480
+R13: ffffffff82012480 R14: 0000000000000000 R15: 0000000000000000
+  ? __sched_text_end+0x4/0x4
+  default_idle+0x18/0xf0
+  do_idle+0x150/0x1d0
+  cpu_startup_entry+0x6f/0x80
+  start_kernel+0x4c4/0x4e4
+  ? set_init_arg+0x55/0x55
+  secondary_startup_64+0xa5/0xb0
+  print_req_error: I/O error, dev nvme0n1, sector 9240
+EXT4-fs error (device nvme0n1): ext4_find_entry:1436:
+inode #2: comm cp: reading directory lblock 0
+
+Example 2: Inject default status code with retry
+------------------------------------------------
+
+mount /dev/nvme0n1 /mnt
+echo 1 > /sys/kernel/debug/nvme0n1/fault_inject/times
+echo 100 > /sys/kernel/debug/nvme0n1/fault_inject/probability
+echo 1 > /sys/kernel/debug/nvme0n1/fault_inject/status
+echo 0 > /sys/kernel/debug/nvme0n1/fault_inject/no_retry
+
+cp a.file /mnt
+
+Expected Result:
+
+command success without error
+
+Message from dmesg:
+
+FAULT_INJECTION: forcing a failure.
+name fault_inject, interval 1, probability 100, space 0, times 1
+CPU: 1 PID: 0 Comm: swapper/1 Not tainted 4.15.0-rc8+ #4
+Hardware name: innotek GmbH VirtualBox/VirtualBox, BIOS VirtualBox 12/01/2006
+Call Trace:
+  <IRQ>
+  dump_stack+0x5c/0x7d
+  should_fail+0x148/0x170
+  nvme_should_fail+0x30/0x60 [nvme_core]
+  nvme_loop_queue_response+0x84/0x110 [nvme_loop]
+  nvmet_req_complete+0x11/0x40 [nvmet]
+  nvmet_bio_done+0x28/0x40 [nvmet]
+  blk_update_request+0xb0/0x310
+  blk_mq_end_request+0x18/0x60
+  flush_smp_call_function_queue+0x3d/0xf0
+  smp_call_function_single_interrupt+0x2c/0xc0
+  call_function_single_interrupt+0xa2/0xb0
+  </IRQ>
+RIP: 0010:native_safe_halt+0x2/0x10
+RSP: 0018:ffffc9000068bec0 EFLAGS: 00000246 ORIG_RAX: ffffffffffffff04
+RAX: ffffffff817a10c0 RBX: ffff88011a3c9680 RCX: 0000000000000000
+RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
+RBP: 0000000000000001 R08: 000000008e38c131 R09: 0000000000000000
+R10: 0000000000000000 R11: 0000000000000000 R12: ffff88011a3c9680
+R13: ffff88011a3c9680 R14: 0000000000000000 R15: 0000000000000000
+  ? __sched_text_end+0x4/0x4
+  default_idle+0x18/0xf0
+  do_idle+0x150/0x1d0
+  cpu_startup_entry+0x6f/0x80
+  start_secondary+0x187/0x1e0
+  secondary_startup_64+0xa5/0xb0
-- 
1.8.3.1

[PATCH v3 0/2] nvme: Add fault injection feature

[Sagi Grimberg]

Thomas,

This looks good to me, Keith/Christoph any feedback?
Or should I take this forward?

[PATCH v3 0/2] nvme: Add fault injection feature

[Thomas Tai]

On 2018-02-05 09:49 AM, Sagi Grimberg wrote:
> Thomas,
> 
> This looks good to me, Keith/Christoph any feedback?
> Or should I take this forward?

Hi Sagi,
Thank you for your review. Any feedback from Keith/Christoph that I can 
help answer?

Thank you,
Thomas


> 
> _______________________________________________
> Linux-nvme mailing list
> Linux-nvme at lists.infradead.org
> http://lists.infradead.org/mailman/listinfo/linux-nvme

[PATCH v3 1/2] nvme: Add fault injection feature

[Keith Busch]

Looks fine to me.

Reviewed-by: Keith Busch <keith.busch at intel.com>

[PATCH v3 2/2] Documentation: nvme: Documentation for nvme fault injection

[Keith Busch]

Also looks fine to me.

Reviewed-by: Keith Busch <keith.busch at intel.com>

[PATCH v3 1/2] nvme: Add fault injection feature

[Thomas Tai]

On 2018-02-07 06:46 PM, Keith Busch wrote:
> Looks fine to me.
> 
> Reviewed-by: Keith Busch <keith.busch at intel.com>

Thank you Keith.

> 
> _______________________________________________
> Linux-nvme mailing list
> Linux-nvme at lists.infradead.org
> http://lists.infradead.org/mailman/listinfo/linux-nvme
> 

[PATCH v3 2/2] Documentation: nvme: Documentation for nvme fault injection

[Thomas Tai]

On 2018-02-07 06:50 PM, Keith Busch wrote:
> Also looks fine to me.
> 
> Reviewed-by: Keith Busch <keith.busch at intel.com>

Thank you Keith.

> 
> _______________________________________________
> Linux-nvme mailing list
> Linux-nvme at lists.infradead.org
> http://lists.infradead.org/mailman/listinfo/linux-nvme
> 

[PATCH v3 2/2] Documentation: nvme: Documentation for nvme fault injection

[Sagi Grimberg]

>> Also looks fine to me.
>>
>> Reviewed-by: Keith Busch <keith.busch at intel.com>
> 
> Thank you Keith.

Will pick it up for 4.17

[PATCH v3 2/2] Documentation: nvme: Documentation for nvme fault injection

[Sagi Grimberg]

> +o NVMe fault injection
> +
> +  inject NVMe NVME_SC_INVALID_OPCODE with no retry on devices permitted
> +  by setting debugfs entries under /sys/kernel/debug/nvme*/fault_inject
> +

Actually, can you update the documentation entry here?

[PATCH v3 2/2] Documentation: nvme: Documentation for nvme fault injection

[Thomas Tai]

On 2018-02-08 10:42 AM, Sagi Grimberg wrote:
> 
>> +o NVMe fault injection
>> +
>> +? inject NVMe NVME_SC_INVALID_OPCODE with no retry on devices permitted
>> +? by setting debugfs entries under /sys/kernel/debug/nvme*/fault_inject
>> +
> 
> Actually, can you update the documentation entry here?

Yes Sagi. I will submit the documentation to the fault injection 
maintainer. Thank you for your help.

Thomas

> 
> _______________________________________________
> Linux-nvme mailing list
> Linux-nvme at lists.infradead.org
> http://lists.infradead.org/mailman/listinfo/linux-nvme

[PATCH v3 2/2] Documentation: nvme: Documentation for nvme fault injection

[Sagi Grimberg]

>>> +o NVMe fault injection
>>> +
>>> +? inject NVMe NVME_SC_INVALID_OPCODE with no retry on devices permitted
>>> +? by setting debugfs entries under /sys/kernel/debug/nvme*/fault_inject
>>> +
>>
>> Actually, can you update the documentation entry here?
> 
> Yes Sagi. I will submit the documentation to the fault injection 
> maintainer. Thank you for your help.

It's going to 4.17 (we have time), so I'd prefer to get it right once
instead of having another fixup on top. Would it be possible to re-spin
with the minor fix?

[PATCH v3 2/2] Documentation: nvme: Documentation for nvme fault injection

[Thomas Tai]

On 2018-02-08 11:05 AM, Sagi Grimberg wrote:
> 
>>>> +o NVMe fault injection
>>>> +
>>>> +? inject NVMe NVME_SC_INVALID_OPCODE with no retry on devices 
>>>> permitted
>>>> +? by setting debugfs entries under 
>>>> /sys/kernel/debug/nvme*/fault_inject
>>>> +
>>>
>>> Actually, can you update the documentation entry here?
>>
>> Yes Sagi. I will submit the documentation to the fault injection 
>> maintainer. Thank you for your help.
> 
> It's going to 4.17 (we have time), so I'd prefer to get it right once
> instead of having another fixup on top. Would it be possible to re-spin
> with the minor fix?

Sure. Do you mean I should resend the patch set which include the fault 
injection maintainer in the email?

[PATCH v3 2/2] Documentation: nvme: Documentation for nvme fault injection

[Sagi Grimberg]

>>>>> +o NVMe fault injection
>>>>> +
>>>>> +? inject NVMe NVME_SC_INVALID_OPCODE with no retry on devices 
>>>>> permitted
>>>>> +? by setting debugfs entries under 
>>>>> /sys/kernel/debug/nvme*/fault_inject
>>>>> +
>>>>
>>>> Actually, can you update the documentation entry here?
>>>
>>> Yes Sagi. I will submit the documentation to the fault injection 
>>> maintainer. Thank you for your help.
>>
>> It's going to 4.17 (we have time), so I'd prefer to get it right once
>> instead of having another fixup on top. Would it be possible to re-spin
>> with the minor fix?
> 
> Sure. Do you mean I should resend the patch set which include the fault 
> injection maintainer in the email?

No, just fix the documentation to say not only NVME_SC_INVALID_OPCODE 
can be injected (the entry in fault-injection.txt)

[PATCH v3 2/2] Documentation: nvme: Documentation for nvme fault injection

[Thomas Tai]

[ ... ]
>>> It's going to 4.17 (we have time), so I'd prefer to get it right once
>>> instead of having another fixup on top. Would it be possible to re-spin
>>> with the minor fix?
>>
>> Sure. Do you mean I should resend the patch set which include the 
>> fault injection maintainer in the email?
> 
> No, just fix the documentation to say not only NVME_SC_INVALID_OPCODE 
> can be injected (the entry in fault-injection.txt)

Oh yes. Sorry I missed that. will update the doc. Thank you.