[PATCH V8 0/1] nvme: allow passthru cmd error logging

[Alan Adamson]

In nvme_end_req() we only log errors which are for non-passthru
commands. Add a helper function nvme_log_err_passthru() that allows us
to log error for passthru commands by decoding cdw10-cdw15 values of
nvme command.

Below is short testlog :-

* Admin Passsthru error log off, no errors are printed
* Admin Passsthru error log on, errors are printed
* IO Passsthru error log off, no errors are printed
* IO Passsthru error log on, errors are printed

v8:
- Add a logging_enabled flag to device structure.
- Add a passthru_err_log_enabled sysfs attribute for namespaces to
  allow logging of passthru IO commands. 

v7:
- Changed attribute/flag to passthru_err_log_enabled.
- Use kstrtobool rather than kstrtoint.

v6:
- Rebase, retest nvme-6.5 and add test log for admin and I/O
  passthru error log.

v5:
- Trim down code in the nvme_log_error_passthrough().
  Use following to get the disk name as an arg to
   pr_err_ratelimited() :-
	ns ? ns->disk->disk_name : dev_name(nr->ctrl->device),
  Use following to get the admin vs I/O opcode string as an arg to
  pr_err_ratelimited() :-
       	ns ? nvme_get_opcode_str(nr->cmd->common.opcode) :
       	     nvme_get_admin_opcode_str(nr->cmd->common.opcode),
- Rename nvme_log_error_passthrough() -> nvme_log_err_passthru().
- Remove else and return directly in nvme_passthru_err_log_show().
- Generate error on invalid values of the passthru_enable variable
  in nvme_passthru_log_store().
- Rename passthrough -> passthru.
- Rename sysfs attr from passthru_admin_err_logging -> passthru_log_err.

v4:
- Change sysfs attribute to passthru_admin_err_logging
- Only log passthrough admin commands.  IO passthrough commands will
  always be logged.

v3:
- Log a passthrough specific message that dumps CDW* contents.
- Enable/disable vis sysfs rather than debugfs.

v2:
- Included Pankaj Raghav's patch 'nvme: ignore starting sector while 
  error logging for passthrough requests'
  with a couple changes.
- Moved error_logging flag to nvme_ctrl structure
- The entire nvme-debugfs.c does not need to be guarded by 
  #ifdef CONFIG_FAULT_INJECTION_DEBUG_FS.
- Use IS_ENABLED((CONFIG_NVME_ERROR_LOGGING_DEBUG_FS)) to determine if 
  error logging should be initialized.
- Various other nits.


Testing
-------
* Admin Passsthru error log off, no errors are printed :-

[root at localhost ~]# echo 0 > /sys/class/nvme/nvme0/passthru_err_log_enabled
[root at localhost ~]# nvme telemetry-log -o /tmp/test /dev/nvme0
[root at localhost ~]# dmesg
[root at localhost ~]


* Admin Passsthru error log on, errors are printed :-

[root at localhost ~]# echo 1 > /sys/class/nvme/nvme0/passthru_err_log_enabled
[root at localhost ~]# nvme telemetry-log -o /tmp/test /dev/nvme0
[root at localhost ~]# dmesg
[ 2364.008105] nvme0: Get Log Page(0x2), Invalid Field in Command (sct 0x0 / sc 0x2) DNR cdw10=0x7f0107 cdw11=0x0 cdw12=0x0 cdw13=0x0 cdw14=0x0 cdw15=0x0


* IO Passsthru error log off, errors are not printed :-

[root at localhost ~]# echo 0 > /sys/class/nvme/nvme0/nvme0n1/passthru_err_log_enabled
[root at localhost ~]# nvme write-zeroes -n 1 -s 0x200000 -c 10 /dev/nvme0
NVMe status: LBA Out of Range: The command references an LBA that exceeds the size of the namespace(0x4080)
[root at localhost ~]# dmesg
[ 3131.602986] nvme nvme0: using deprecated NVME_IOCTL_IO_CMD ioctl on the char device!
[root at localhost ~]# 


* IO Passsthru error log on, errors are printed :-

[root at localhost ~]# echo 1 > /sys/class/nvme/nvme0/nvme0n1/passthru_err_log_enabled
[root at localhost ~]# nvme write-zeroes -n 1 -s 0x200000 -c 10 /dev/nvme0
NVMe status: LBA Out of Range: The command references an LBA that exceeds the size of the namespace(0x4080)
[root at localhost ~]# dmesg
[ 2944.910393] nvme nvme0: using deprecated NVME_IOCTL_IO_CMD ioctl on the char device!
[ 2944.910423] nvme0n1: Write Zeroes(0x8), LBA Out of Range (sct 0x0 / sc 0x80) DNR cdw10=0x200000 cdw11=0x0 cdw12=0xa cdw13=0x0 cdw14=0x0 cdw15=0x0
[root at localhost ~]# 

Alan Adamson (1):
  nvme: allow passthru cmd error logging

 drivers/nvme/host/core.c  | 52 ++++++++++++++++++++++++++++++++++-----
 drivers/nvme/host/nvme.h  |  2 ++
 drivers/nvme/host/sysfs.c | 44 +++++++++++++++++++++++++++++++++
 include/linux/device.h    |  1 +
 4 files changed, 93 insertions(+), 6 deletions(-)

-- 
2.39.3