Re: [PATCH v3 2/4] scsi: scsi_error: Add counters for New Media and Power On/Reset UNIT ATTENTIONs

[John Meneghini <jmeneghi@redhat.com>]

Reviewed-by: John Meneghini <jmeneghi@redhat.com>
Tested-by: John Meneghini <jmeneghi@redhat.com>

On 1/20/25 2:49 PM, Kai Mäkisara wrote:
> The purpose of the counters is to enable all ULDs attached to a
> device to find out that a New Media or/and Power On/Reset Unit
> Attentions has/have been set, even if another ULD catches the
> Unit Attention as response to a SCSI command.
> 
> The ULDs can read the counters and see if the values have changed from
> the previous check.
> 
> Signed-off-by: Kai Mäkisara <Kai.Makisara@kolumbus.fi>
> ---
>   drivers/scsi/scsi_error.c  | 12 ++++++++++++
>   include/scsi/scsi_device.h |  3 +++
>   2 files changed, 15 insertions(+)
> 
> diff --git a/drivers/scsi/scsi_error.c b/drivers/scsi/scsi_error.c
> index 10154d78e336..6ef0711c4ec3 100644
> --- a/drivers/scsi/scsi_error.c
> +++ b/drivers/scsi/scsi_error.c
> @@ -547,6 +547,18 @@ enum scsi_disposition scsi_check_sense(struct scsi_cmnd *scmd)
>   
>   	scsi_report_sense(sdev, &sshdr);
>   
> +	if (sshdr.sense_key == UNIT_ATTENTION) {
> +		/*
> +		 * increment the counters for Power on/Reset or New Media so
> +		 * that all ULDs interested in these can see that those have
> +		 * happened, even if someone else gets the sense data.
> +		 */
> +		if (sshdr.asc == 0x28)
> +			scmd->device->ua_new_media_ctr++;
> +		else if (sshdr.asc == 0x29)
> +			scmd->device->ua_por_ctr++;
> +	}
> +
>   	if (scsi_sense_is_deferred(&sshdr))
>   		return NEEDS_RETRY;
>   
> diff --git a/include/scsi/scsi_device.h b/include/scsi/scsi_device.h
> index 9c540f5468eb..f5c0f07a053a 100644
> --- a/include/scsi/scsi_device.h
> +++ b/include/scsi/scsi_device.h
> @@ -247,6 +247,9 @@ struct scsi_device {
>   	unsigned int queue_stopped;	/* request queue is quiesced */
>   	bool offline_already;		/* Device offline message logged */
>   
> +	u16 ua_new_media_ctr;		/* Counter for New Media UNIT ATTENTIONs */
> +	u16 ua_por_ctr;			/* Counter for Power On / Reset UAs */
> +
>   	atomic_t disk_events_disable_depth; /* disable depth for disk events */
>   
>   	DECLARE_BITMAP(supported_events, SDEV_EVT_MAXBITS); /* supported events */