Hi all,
I have encountered a really nice aliasing error in the SCSI stack.
(I only hope Luben is not reading this, it'll be just the thing he'd
want to hear :-)
Some device allow for a max lun number larger than 16k.
Eg qla2xxx has this:
#define MAX_FIBRE_LUNS 0xFFFF
If we encounter a SCSI-2 device with has
BLIST_SPARSELUN | BLIST_LARGELUN
set we'll end up doing a sequential scan of all 64k luns.
However, according to SAM the top two bits are reserved for hierarchical
addressing. So if we're using a lun _number_ larger than 16k we'll
infact are using the flat addressing model of the LUN with mask 0xC000.
So essentially a device at LUN 0x0 will be aliased to LUN 0xC000 et al
and hence will be seen detected several times from SCSI ML.
The easy way out here is to _not_ scan past 16k; this will 'fix' this
issue. Affected drivers are qla2xxx and lpfc.
However, I feel in the long run we should at least detect hierarchical
luns and issue a warning there. Just think of hierarchical LUNs being
returned from REPORT_LUNS ...
Signed-off-by: Hannes Reinecke <hare@xxxxxxx>
Cheers,
Hannes
--
Dr. Hannes Reinecke hare@xxxxxxx
SuSE Linux Products GmbH S390 & zSeries
Maxfeldstraße 5 +49 911 74053 688
90409 Nürnberg http://www.suse.de
diff --git a/drivers/scsi/lpfc/lpfc_attr.c b/drivers/scsi/lpfc/lpfc_attr.c
index b62a72d..af4dd6f 100644
--- a/drivers/scsi/lpfc/lpfc_attr.c
+++ b/drivers/scsi/lpfc/lpfc_attr.c
@@ -696,10 +696,10 @@ LPFC_ATTR(discovery_threads, 32, 1, 64,
/*
# lpfc_max_luns: maximum number of LUNs per target driver will support
-# Value range is [1,32768]. Default value is 256.
+# Value range is [1,16384]. Default value is 256.
# NOTE: The SCSI layer will scan each target for this many luns
*/
-LPFC_ATTR_R(max_luns, 256, 1, 32768,
+LPFC_ATTR_R(max_luns, 256, 1, 16384,
"Maximum number of LUNs per target driver will support");
/*
diff --git a/drivers/scsi/qla2xxx/qla_def.h b/drivers/scsi/qla2xxx/qla_def.h
index 139ea0e..3183ad7 100644
--- a/drivers/scsi/qla2xxx/qla_def.h
+++ b/drivers/scsi/qla2xxx/qla_def.h
@@ -119,7 +119,7 @@ #define WRT_REG_WORD_PIO(addr, data) (ou
*/
#define WWN_SIZE 8 /* Size of WWPN, WWN & WWNN */
#define MAX_FIBRE_DEVICES 512
-#define MAX_FIBRE_LUNS 0xFFFF
+#define MAX_FIBRE_LUNS 0x3FFF
#define MAX_RSCN_COUNT 32
#define MAX_HOST_COUNT 16
