Some SCSI tape medium changers that need the BLIST_SINGLELUN flag have
the medium changer at one LUN and the tape drive at a different LUN.
The inquiry string of the tape drive may be different from that of the
medium changer. In order for single_lun to be effective, every
scsi_device under a given scsi_target must have it set. This means that
there needs to be a blacklist entry for BOTH the medium changer AND the
tape drive, which is impractical because some medium changers may be
paired with a variety of different tape drive models. It makes more
sense to put the single_lun flag in scsi_target instead of scsi_device,
which causes every device at a given target ID to inherit the single_lun
flag from one LUN. This makes it possible to blacklist just the medium
changer and not the tape drive.
Signed-off-by: Tony Battersby <tonyb@xxxxxxxxxxxxxxx>
---
diff -urpN linux-2.6.24-rc2-vanilla/drivers/scsi/scsi_lib.c linux-2.6.24-rc2/drivers/scsi/scsi_lib.c
--- linux-2.6.24-rc2-vanilla/drivers/scsi/scsi_lib.c 2007-11-09 16:48:57.000000000 -0500
+++ linux-2.6.24-rc2/drivers/scsi/scsi_lib.c 2007-11-09 16:54:27.000000000 -0500
@@ -524,7 +524,7 @@ static void scsi_run_queue(struct reques
struct Scsi_Host *shost = sdev->host;
unsigned long flags;
- if (sdev->single_lun)
+ if (scsi_target(sdev)->single_lun)
scsi_single_lun_run(sdev);
spin_lock_irqsave(shost->host_lock, flags);
@@ -1557,7 +1557,7 @@ static void scsi_request_fn(struct reque
if (!scsi_host_queue_ready(q, shost, sdev))
goto not_ready;
- if (sdev->single_lun) {
+ if (scsi_target(sdev)->single_lun) {
if (scsi_target(sdev)->starget_sdev_user &&
scsi_target(sdev)->starget_sdev_user != sdev)
goto not_ready;
diff -urpN linux-2.6.24-rc2-vanilla/drivers/scsi/scsi_scan.c linux-2.6.24-rc2/drivers/scsi/scsi_scan.c
--- linux-2.6.24-rc2-vanilla/drivers/scsi/scsi_scan.c 2007-11-09 16:48:57.000000000 -0500
+++ linux-2.6.24-rc2/drivers/scsi/scsi_scan.c 2007-11-09 16:55:59.000000000 -0500
@@ -863,7 +863,7 @@ static int scsi_add_lun(struct scsi_devi
sdev->no_start_on_add = 1;
if (*bflags & BLIST_SINGLELUN)
- sdev->single_lun = 1;
+ scsi_target(sdev)->single_lun = 1;
sdev->use_10_for_rw = 1;
diff -urpN linux-2.6.24-rc2-vanilla/include/scsi/scsi_device.h linux-2.6.24-rc2/include/scsi/scsi_device.h
--- linux-2.6.24-rc2-vanilla/include/scsi/scsi_device.h 2007-11-09 16:49:05.000000000 -0500
+++ linux-2.6.24-rc2/include/scsi/scsi_device.h 2007-11-09 16:53:43.000000000 -0500
@@ -122,9 +122,6 @@ struct scsi_device {
unsigned tagged_supported:1; /* Supports SCSI-II tagged queuing */
unsigned simple_tags:1; /* simple queue tag messages are enabled */
unsigned ordered_tags:1;/* ordered queue tag messages are enabled */
- unsigned single_lun:1; /* Indicates we should only allow I/O to
- * one of the luns for the device at a
- * time. */
unsigned was_reset:1; /* There was a bus reset on the bus for
* this device */
unsigned expecting_cc_ua:1; /* Expecting a CHECK_CONDITION/UNIT_ATTN
@@ -202,6 +199,9 @@ struct scsi_target {
unsigned int id; /* target id ... replace
* scsi_device.id eventually */
unsigned int create:1; /* signal that it needs to be added */
+ unsigned int single_lun:1; /* Indicates we should only
+ * allow I/O to one of the luns
+ * for the device at a time. */
unsigned int pdt_1f_for_no_lun; /* PDT = 0x1f */
/* means no lun present */
-
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