nvme: fix parameter check in nvme_fault_inject_init()

Make IS_ERR() judge the debugfs_create_dir() function return.

Signed-off-by: Minjie Du <duminjie@vivo.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Keith Busch <kbusch@kernel.org>

block: remove the ->rq_disk field in struct request

Just use the disk attached to the request_queue instead.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Chaitanya Kulkarni <kch@nvidia.com>
Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com>
Link: https://lore.kernel.org/r/20211126121802.2090656-4-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>

nvme: enable to inject errors into admin commands

This enables to inject errors into the commands submitted to the admin
queue.

It is useful to test error handling in the controller initialization.

# echo 100 > /sys/kernel/debug/nvme0/fault_inject/probability
# echo 1 > /sys/kernel/debug/nvme0/fault_inject/times
# echo 10 > /sys/kernel/debug/nvme0/fault_inject/space
# nvme reset /dev/nvme0
# dmesg
...
nvme nvme0: Could not set queue count (16385)
nvme nvme0: IO queues not created

Signed-off-by: Akinobu Mita <akinobu.mita@gmail.com>
Reviewed-by: Minwoo Im <minwoo.im.dev@gmail.com>
Reviewed-by: Sagi Grimberg <sagi@grimberg.me>
Reviewed-by: Chaitanya Kulkarni <chaitanya.kulkarni@wdc.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Christoph Hellwig <hch@lst.de>

nvme: prepare for fault injection into admin commands

Currenlty fault injection support for nvme only enables to inject errors
into the commands submitted to I/O queues.

In preparation for fault injection into the admin commands, this makes
the helper functions independent of struct nvme_ns.

Signed-off-by: Akinobu Mita <akinobu.mita@gmail.com>
Reviewed-by: Minwoo Im <minwoo.im.dev@gmail.com>
Reviewed-by: Sagi Grimberg <sagi@grimberg.me>
Reviewed-by: Chaitanya Kulkarni <chaitanya.kulkarni@wdc.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>

nvme: convert to SPDX identifiers

Update license to use SPDX-License-Identifier instead of verbose license
text.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Sagi Grimberg <sagi@grimberg.me>

nvme: Add fault injection feature

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@oracle.com>
Reviewed-by: Eric Saint-Etienne <eric.saint.etienne@oracle.com>
Signed-off-by: Karl Volz <karl.volz@oracle.com>
Reviewed-by: Keith Busch <keith.busch@intel.com>
Signed-off-by: Sagi Grimberg <sagi@grimberg.me>
Signed-off-by: Jens Axboe <axboe@kernel.dk>