On Tue, Apr 25, 2023 at 04:34:46PM -0700, Bart Van Assche wrote:
> If a command fails, SCSI sense data is essential to determine why it
> failed. Hence make the SCSI sense data available in the ftrace output.
>
> Cc: Christoph Hellwig <hch@xxxxxx>
> Cc: Ming Lei <ming.lei@xxxxxxxxxx>
> Cc: Hannes Reinecke <hare@xxxxxxx>
> Cc: John Garry <john.g.garry@xxxxxxxxxx>
> Cc: Mike Christie <michael.christie@xxxxxxxxxx>
> Signed-off-by: Bart Van Assche <bvanassche@xxxxxxx>
> ---
> include/trace/events/scsi.h | 17 +++++++++++++++--
> 1 file changed, 15 insertions(+), 2 deletions(-)
>
> diff --git a/include/trace/events/scsi.h b/include/trace/events/scsi.h
> index a2c7befd451a..bb5f31504fbb 100644
> --- a/include/trace/events/scsi.h
> +++ b/include/trace/events/scsi.h
> @@ -269,6 +269,7 @@ DECLARE_EVENT_CLASS(scsi_cmd_done_timeout_template,
> __field( unsigned int, prot_sglen )
> __field( unsigned char, prot_op )
> __dynamic_array(unsigned char, cmnd, cmd->cmd_len)
> + __array(unsigned char, sense_data, SCSI_SENSE_BUFFERSIZE)
> ),
>
> TP_fast_assign(
> @@ -285,11 +286,13 @@ DECLARE_EVENT_CLASS(scsi_cmd_done_timeout_template,
> __entry->prot_sglen = scsi_prot_sg_count(cmd);
> __entry->prot_op = scsi_get_prot_op(cmd);
> memcpy(__get_dynamic_array(cmnd), cmd->cmnd, cmd->cmd_len);
> + memcpy(__entry->sense_data, cmd->sense_buffer,
> + SCSI_SENSE_BUFFERSIZE);
> ),
>
> TP_printk("host_no=%u channel=%u id=%u lun=%u data_sgl=%u prot_sgl=%u " \
> "prot_op=%s driver_tag=%d scheduler_tag=%d cmnd=(%s %s raw=%s) " \
> - "result=(driver=%s host=%s message=%s status=%s)",
> + "result=(driver=%s host=%s message=%s status=%s%s%s)",
> __entry->host_no, __entry->channel, __entry->id,
> __entry->lun, __entry->data_sglen, __entry->prot_sglen,
> show_prot_op_name(__entry->prot_op), __entry->driver_tag,
> @@ -299,7 +302,17 @@ DECLARE_EVENT_CLASS(scsi_cmd_done_timeout_template,
> "DRIVER_OK",
> show_hostbyte_name(((__entry->result) >> 16) & 0xff),
> "COMMAND_COMPLETE",
> - show_statusbyte_name(__entry->result & 0xff))
> + show_statusbyte_name(__entry->result & 0xff),
> + __entry->result & 0xff ? " sense_data=" : "",
> + __entry->result & 0xff ?
> + ({
> + unsigned int len = SCSI_SENSE_BUFFERSIZE;
> +
> + while (len && __entry->sense_data[len - 1] == 0)
> + len--;
> + __print_hex(__entry->sense_data, len);
Hello Bart,
Do we really need to dump the whole sense buffer?
Shouldn't simply printing the SK, ASC, ASCQ be sufficient?
Yes, it is a bit annoying that there are two different formats.
But you could do the reverse of:
https://github.com/torvalds/linux/blob/v6.3/drivers/scsi/scsi_common.c#L241
Or, if the tracepoint is after scsi_normalize_sense() has been called,
you could simply use sshdr->sense_key, sshdr->asc and sshdr->ascq.
Kind regards,
Niklas
