scsi: core: Add counters for New Media and Power On/Reset UNIT ATTENTIONs

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 <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Reviewed-by: John Meneghini <[email protected]>
Tested-by: John Meneghini <[email protected]>
Signed-off-by: Martin K. Petersen <[email protected]>

Author: kmakisara

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;
 

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 */
 
+	unsigned int ua_new_media_ctr;	/* Counter for New Media UNIT ATTENTIONs */
+	unsigned int 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 */