This is a somewhat imperfect means to try and bring FreeBSD forward in

its ability to automatically scan and attach luns for modern storage
which has luns in the 0..1000 range, not 0..7.

The correct thing would be to do REPORT LUNS for devices whose LUN0
version shows a version >= SCSI3, but lacking that we should be able
to search higher than LUN 7 if we're >= SCSI3 with no ill effects.

This change keeps all of the QUIRK_HILUNS quirks, obeys the QUIRK_NOLUNS,
and introduces a QUIRK_NOHILUNS which will keep searches above LUN 7
happening for devices that report >= SCSI3 compliance. I doubt the latter
will be needed, but you never know.

This allowed me to randomly scan and attach  > 500 disks at a time in
a situation where quirking for QUIRK_HILUNS wasn't practical (the
vendor id and product id changes of the virtualization changes
constantly).

Reviewed by:	ken@freebsd.org, scottl@freebsd.org, gibbs@freebsd.org
MFC after:	2 weeks

1 files changed, 13 insertions, 3 deletions

diff --git a/sys/cam/cam_xpt.c b/sys/cam/cam_xpt.c
index 84c8f2a..29b836d 100644
--- a/sys/cam/cam_xpt.c
+++ b/sys/cam/cam_xpt.c
@@ -199,10 +199,20 @@ struct xpt_quirk_entry {
 #define	CAM_QUIRK_NOLUNS	0x01
 #define	CAM_QUIRK_NOSERIAL	0x02
 #define	CAM_QUIRK_HILUNS	0x04
+#define	CAM_QUIRK_NOHILUNS	0x08
 	u_int mintags;
 	u_int maxtags;
 };
 #define	CAM_SCSI2_MAXLUN	8
+/*
+ * If we're not quirked to search <= the first 8 luns
+ * and we are either quirked to search above lun 8,
+ * or we're > SCSI-2, we can look for luns above lun 8.
+ */
+#define	CAN_SRCH_HI(dv)					\
+  (((dv->quirk->quirks & CAM_QUIRK_NOHILUNS) == 0) 	\
+  && ((dv->quirk->quirks & CAM_QUIRK_HILUNS)		\
+  || SID_ANSI_REV(&dv->inq_data) > SCSI_REV_2))
 
 typedef enum {
 	XPT_FLAG_OPEN		= 0x01
@@ -5294,7 +5304,7 @@ xpt_scan_bus(struct cam_periph *periph, union ccb *request_ccb)
 			s = splcam();
 			device = TAILQ_FIRST(&target->ed_entries);
 			if (device != NULL) {
-				phl = device->quirk->quirks & CAM_QUIRK_HILUNS;
+				phl = CAN_SRCH_HI(device);
 				if (device->lun_id == 0)
 					device = TAILQ_NEXT(device, links);
 			}
@@ -5310,8 +5320,8 @@ xpt_scan_bus(struct cam_periph *periph, union ccb *request_ccb)
 
 			if ((device->quirk->quirks & CAM_QUIRK_NOLUNS) == 0) {
 				/* Try the next lun */
-				if (lun_id < (CAM_SCSI2_MAXLUN-1) ||
-				    (device->quirk->quirks & CAM_QUIRK_HILUNS))
+				if (lun_id < (CAM_SCSI2_MAXLUN-1)
+				  || CAN_SRCH_HI(device))
 					lun_id++;
 			}
 		}