[PATCH V6 0/1] nvme: Add verbose error logging

[Alan Adamson <alan.adamson@oracle.com>]

V6:
- Create helpers that are stubbed out if CONFIG_NVME_VERBOSE_ERRORS is not set.
- Couple more nits.

V5:
- Change nvme_ops[] and nvme_admin_ops[] to a sparse array where the opcode is used as an index into the array.
- Various other nits.

V4:
- Adding logging for admin commands.
- Display NVMe Command Opcode value rather than generic block opcode.
- Various other nits.

V3:
- Don't populate nvme_errors[] array with NULL strings.

V2:
- Change nvme_errors[] to a sparse array where the status is used as an index into the array.

- Change pr_err() to pr_err_ratelimited().

- By enabling CONFIG_NVME_VERBOSE_ERRORS, the verbose status error is displayed.  If it is not
enabled, then a message will still be displayed, but without the verbose status.

- Remove call to nvme_error_status() when determining whether to call nvme_error_log().  Speeds
up the fast path just a bit.


This patch improves logging for NVMe errors.  Currently, we only get a
a vague idea as to why commands fail since only the block layer status
is captured on error. This patch allows us to see why a command was failed
by the controller. This is very useful when debugging problems in the field.

An example of an improved logged error:

[  183.333734] nvme0n1: Read(0x2) @ LBA 0, 1 blocks, Unrecovered Read Error (sct 0x2 / sc 0x81) DNR

[  227.767945] nvme0: Activate Firmware(0x10), Invalid Field in Command (sct 0x0 / sc 0x2) DNR

Alan Adamson (1):
  nvme: Add verbose error logging

 drivers/nvme/host/Kconfig  |   8 ++
 drivers/nvme/host/Makefile |   2 +-
 drivers/nvme/host/core.c   |  41 ++++++++
 drivers/nvme/host/errors.c | 206 +++++++++++++++++++++++++++++++++++++
 drivers/nvme/host/nvme.h   |  20 ++++
 include/linux/nvme.h       |   1 +
 6 files changed, 277 insertions(+), 1 deletion(-)
 create mode 100644 drivers/nvme/host/errors.c

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2.27.0