RFC/patch: bflags not applied in case of SCSI_SCAN_TARGET_PRESENT

RFC/patch: bflags not applied in case of SCSI_SCAN_TARGET_PRESENT

[Guido Guenther]

Hi,
we're using a qla2342 together with an EMC Symmetric. SCSI scanning the
EMC reports a peripheral identifier of 3 for lun 0, which leads to
a SCSI_SCAN_PRESENT return code of scsi_probe_and_add_lun, but the
devices blacklist flags are not being honored. This is a problem since
we need SCSI_LARGELUN for successfull scanning on LUNs past 8 in
scsi_scan_target. The attached patch tries to fix this:

a) makes sure we honor the bflags in scsi_probe_and_add_lun, even when
   there's no device supported on this lun (lun 0 is special so it might
   make sense to special case this for lun 0 only)
b) passes them on to the sequential scanning part of scsi_scan_target.

--- linux-2.6.10-rc3.real-orig/drivers/scsi/scsi_scan.c	2004-12-09 18:48:39.000000000 +0100
+++ linux-2.6.10-rc3/drivers/scsi/scsi_scan.c	2004-12-10 12:03:59.000000000 +0100
@@ -717,6 +730,8 @@
 					"scsi scan: peripheral qualifier of 3,"
 					" no device added\n"));
 		res = SCSI_SCAN_TARGET_PRESENT;
+		if (bflagsp)
+			*bflagsp = bflags;
 		goto out_free_result;
 	}
 
@@ -1157,10 +1179,10 @@
 		/*
 		 * There's a target here, but lun 0 is offline so we
 		 * can't use the report_lun scan.  Fall back to a
-		 * sequential lun scan with a bflags of SPARSELUN and
+		 * sequential lun scan with a bflags of at least SPARSELUN and
 		 * a default scsi level of SCSI_2
 		 */
-		scsi_sequential_lun_scan(shost, channel, id, BLIST_SPARSELUN,
+		scsi_sequential_lun_scan(shost, channel, id, BLIST_SPARSELUN | bflags,
 				SCSI_SCAN_TARGET_PRESENT, SCSI_2, rescan);
 	}
 }

Does this look o.k.? Patch is against 2.6.10-rc3. I know little about
scsi scanning, so this might be completely bogus.
Please cc: me on replies since I'm not subscribe to this list.
Cheers,
 -- Guido

[PATCH] REPORT LUN scan even if no storage is available on LUN 0

[Patrick Mansfield]

Patch looks okay, but we should always be trying the report lun scan, and
then failing back to the sequential scan even if there is no storage on
LUN 0.

Can you test this? I don't have hardware readily available that supports
sparse luns and report lun. Patch is against current bk. I built and
ran with regular disks (lun 0 only).

This is a bit hacky, improvements welcomed. Ideally we should create and
then use a scsi_target to scan, rather than having the scsi_device
allocation trigger creation of the scsi_target, and pass a scsi_target to
other scan functions.


Support REPORT LUN scan even if no storage is available on LUN 0.

Signed-off-by: Patrick Mansfield <patmans@us.ibm.com>

--- 1.134/drivers/scsi/scsi_scan.c	Sun Oct 24 04:09:48 2004
+++ edited/drivers/scsi/scsi_scan.c	Mon Dec 13 13:23:37 2004
@@ -647,6 +647,9 @@
  *     Call scsi_probe_lun, if a LUN with an attached device is found,
  *     allocate and set it up by calling scsi_add_lun.
  *
+ * Note: LUN 0 is special cased, the sdev is not released if we are
+ *     returning SCSI_SCAN_TARGET_PRESENT.
+ *
  * Return:
  *     SCSI_SCAN_NO_RESPONSE: could not allocate or setup a Scsi_Device
  *     SCSI_SCAN_TARGET_PRESENT: target responded, but no device is
@@ -735,7 +738,12 @@
  out_free_sreq:
 	scsi_release_request(sreq);
  out_free_sdev:
-	if (res == SCSI_SCAN_LUN_PRESENT) {
+	if ((res == SCSI_SCAN_LUN_PRESENT) ||
+	    ((lun == 0) && res == SCSI_SCAN_TARGET_PRESENT)) {
+		/*
+		 * The LUN 0 check is for support of report lun scanning
+		 * when no storage is configured on LUN 0.
+		 */
 		if (sdevp)
 			*sdevp = sdev;
 	} else {
@@ -1076,6 +1084,8 @@
 	down(&shost->scan_mutex);
 	res = scsi_probe_and_add_lun(shost, channel, id, lun, NULL,
 				     &sdev, 1, hostdata);
+	if ((lun == 0) && (res == SCSI_SCAN_TARGET_PRESENT))
+		put_device(&sdev->sdev_gendev);
 	if (res != SCSI_SCAN_LUN_PRESENT)
 		sdev = ERR_PTR(-ENODEV);
 	up(&shost->scan_mutex);
@@ -1134,18 +1144,19 @@
 		/*
 		 * Scan for a specific host/chan/id/lun.
 		 */
-		scsi_probe_and_add_lun(shost, channel, id, lun, NULL, NULL,
-				       rescan, NULL);
-		return;
+		res = scsi_probe_and_add_lun(shost, channel, id, lun, NULL,
+					     &sdev, rescan, NULL);
+		goto completed;
 	}
 
 	/*
 	 * Scan LUN 0, if there is some response, scan further. Ideally, we
 	 * would not configure LUN 0 until all LUNs are scanned.
 	 */
-	res = scsi_probe_and_add_lun(shost, channel, id, 0, &bflags, &sdev,
+	lun = 0;
+	res = scsi_probe_and_add_lun(shost, channel, id, lun, &bflags, &sdev,
 				     rescan, NULL);
-	if (res == SCSI_SCAN_LUN_PRESENT) {
+	if (res != SCSI_SCAN_NO_RESPONSE) {
 		if (scsi_report_lun_scan(sdev, bflags, rescan) != 0)
 			/*
 			 * The REPORT LUN did not scan the target,
@@ -1153,16 +1164,15 @@
 			 */
 			scsi_sequential_lun_scan(shost, channel, id, bflags,
 				       	res, sdev->scsi_level, rescan);
-	} else if (res == SCSI_SCAN_TARGET_PRESENT) {
+	}
+
+ completed:
+	if ((lun == 0) && (res == SCSI_SCAN_TARGET_PRESENT))
 		/*
-		 * There's a target here, but lun 0 is offline so we
-		 * can't use the report_lun scan.  Fall back to a
-		 * sequential lun scan with a bflags of SPARSELUN and
-		 * a default scsi level of SCSI_2
+		 * LUN 0 is handled specially so the sdev can be
+		 * used with the REPORT LUN scan, release it now.
 		 */
-		scsi_sequential_lun_scan(shost, channel, id, BLIST_SPARSELUN,
-				SCSI_SCAN_TARGET_PRESENT, SCSI_2, rescan);
-	}
+		put_device(&sdev->sdev_gendev);
 }
 
 static void scsi_scan_channel(struct Scsi_Host *shost, unsigned int channel,

Re: [PATCH] REPORT LUN scan even if no storage is available on LUN 0

[Guido Guenther]

Sorry it took me so long to test this, first time I'm near this hardware
again.
On Mon, Dec 13, 2004 at 02:22:06PM -0800, Patrick Mansfield wrote:
> Patch looks okay, but we should always be trying the report lun scan, and
> then failing back to the sequential scan even if there is no storage on
> LUN 0.

> Can you test this? I don't have hardware readily available that supports
> sparse luns and report lun. Patch is against current bk. I built and
> ran with regular disks (lun 0 only).
Doesn't work here. I doen't see any devices in /proc/scsi/scsi now.
 -- Guido

> 
> This is a bit hacky, improvements welcomed. Ideally we should create and
> then use a scsi_target to scan, rather than having the scsi_device
> allocation trigger creation of the scsi_target, and pass a scsi_target to
> other scan functions.
> 
> 
> Support REPORT LUN scan even if no storage is available on LUN 0.
> 
> Signed-off-by: Patrick Mansfield <patmans@us.ibm.com>
> 
> --- 1.134/drivers/scsi/scsi_scan.c	Sun Oct 24 04:09:48 2004
> +++ edited/drivers/scsi/scsi_scan.c	Mon Dec 13 13:23:37 2004
> @@ -647,6 +647,9 @@
>   *     Call scsi_probe_lun, if a LUN with an attached device is found,
>   *     allocate and set it up by calling scsi_add_lun.
>   *
> + * Note: LUN 0 is special cased, the sdev is not released if we are
> + *     returning SCSI_SCAN_TARGET_PRESENT.
> + *
>   * Return:
>   *     SCSI_SCAN_NO_RESPONSE: could not allocate or setup a Scsi_Device
>   *     SCSI_SCAN_TARGET_PRESENT: target responded, but no device is
> @@ -735,7 +738,12 @@
>   out_free_sreq:
>  	scsi_release_request(sreq);
>   out_free_sdev:
> -	if (res == SCSI_SCAN_LUN_PRESENT) {
> +	if ((res == SCSI_SCAN_LUN_PRESENT) ||
> +	    ((lun == 0) && res == SCSI_SCAN_TARGET_PRESENT)) {
> +		/*
> +		 * The LUN 0 check is for support of report lun scanning
> +		 * when no storage is configured on LUN 0.
> +		 */
>  		if (sdevp)
>  			*sdevp = sdev;
>  	} else {
> @@ -1076,6 +1084,8 @@
>  	down(&shost->scan_mutex);
>  	res = scsi_probe_and_add_lun(shost, channel, id, lun, NULL,
>  				     &sdev, 1, hostdata);
> +	if ((lun == 0) && (res == SCSI_SCAN_TARGET_PRESENT))
> +		put_device(&sdev->sdev_gendev);
>  	if (res != SCSI_SCAN_LUN_PRESENT)
>  		sdev = ERR_PTR(-ENODEV);
>  	up(&shost->scan_mutex);
> @@ -1134,18 +1144,19 @@
>  		/*
>  		 * Scan for a specific host/chan/id/lun.
>  		 */
> -		scsi_probe_and_add_lun(shost, channel, id, lun, NULL, NULL,
> -				       rescan, NULL);
> -		return;
> +		res = scsi_probe_and_add_lun(shost, channel, id, lun, NULL,
> +					     &sdev, rescan, NULL);
> +		goto completed;
>  	}
>  
>  	/*
>  	 * Scan LUN 0, if there is some response, scan further. Ideally, we
>  	 * would not configure LUN 0 until all LUNs are scanned.
>  	 */
> -	res = scsi_probe_and_add_lun(shost, channel, id, 0, &bflags, &sdev,
> +	lun = 0;
> +	res = scsi_probe_and_add_lun(shost, channel, id, lun, &bflags, &sdev,
>  				     rescan, NULL);
> -	if (res == SCSI_SCAN_LUN_PRESENT) {
> +	if (res != SCSI_SCAN_NO_RESPONSE) {
>  		if (scsi_report_lun_scan(sdev, bflags, rescan) != 0)
>  			/*
>  			 * The REPORT LUN did not scan the target,
> @@ -1153,16 +1164,15 @@
>  			 */
>  			scsi_sequential_lun_scan(shost, channel, id, bflags,
>  				       	res, sdev->scsi_level, rescan);
> -	} else if (res == SCSI_SCAN_TARGET_PRESENT) {
> +	}
> +
> + completed:
> +	if ((lun == 0) && (res == SCSI_SCAN_TARGET_PRESENT))
>  		/*
> -		 * There's a target here, but lun 0 is offline so we
> -		 * can't use the report_lun scan.  Fall back to a
> -		 * sequential lun scan with a bflags of SPARSELUN and
> -		 * a default scsi level of SCSI_2
> +		 * LUN 0 is handled specially so the sdev can be
> +		 * used with the REPORT LUN scan, release it now.
>  		 */
> -		scsi_sequential_lun_scan(shost, channel, id, BLIST_SPARSELUN,
> -				SCSI_SCAN_TARGET_PRESENT, SCSI_2, rescan);
> -	}
> +		put_device(&sdev->sdev_gendev);
>  }
>  
>  static void scsi_scan_channel(struct Scsi_Host *shost, unsigned int channel,

Re: [PATCH] REPORT LUN scan even if no storage is available on LUN 0

[Patrick Mansfield]

On Mon, Jan 10, 2005 at 05:42:00PM +0100, Guido Guenther wrote:
> Sorry it took me so long to test this, first time I'm near this hardware
> again.
> On Mon, Dec 13, 2004 at 02:22:06PM -0800, Patrick Mansfield wrote:
> > Patch looks okay, but we should always be trying the report lun scan, and
> > then failing back to the sequential scan even if there is no storage on
> > LUN 0.
> 
> > Can you test this? I don't have hardware readily available that supports
> > sparse luns and report lun. Patch is against current bk. I built and
> > ran with regular disks (lun 0 only).
> Doesn't work here. I doen't see any devices in /proc/scsi/scsi now.
>  -- Guido

So it worked some without the patch (I think you only saw some of the LUNs
before)?

What is output during the scan?

Can you turn on some scsi logging, and send that?

If you have root on scsi, you should shutdown syslogd (though this should
not generate lots of logging for small amounts of IO it generates some,
and if you screw up you'll be able to disable the logging), and then 
capture the console/serial output.

If root on ide, just leave syslog on and get /var/log/messages output.

Turn on per-command and scan logging (0x2400 | 0x01c0):

	sysctl -w dev.scsi.logging_level=0x25c0

Set back off afterwards with:

	sysctl -w dev.scsi.logging_level=0

-- Patrick Mansfield

Re: [PATCH] REPORT LUN scan even if no storage is available on LUN 0

[Guido Guenther]

On Tue, Jan 11, 2005 at 10:15:00AM -0800, Patrick Mansfield wrote:
> On Mon, Jan 10, 2005 at 05:42:00PM +0100, Guido Guenther wrote:
> > Sorry it took me so long to test this, first time I'm near this hardware
> > again.
> > On Mon, Dec 13, 2004 at 02:22:06PM -0800, Patrick Mansfield wrote:
> > > Patch looks okay, but we should always be trying the report lun scan, and
> > > then failing back to the sequential scan even if there is no storage on
> > > LUN 0.
> > 
> > > Can you test this? I don't have hardware readily available that supports
> > > sparse luns and report lun. Patch is against current bk. I built and
> > > ran with regular disks (lun 0 only).
> > Doesn't work here. I doen't see any devices in /proc/scsi/scsi now.
> >  -- Guido
> 
> So it worked some without the patch (I think you only saw some of the LUNs
> before)?
No. Without any patches we had all the available devices in
/proc/scsi/scsi but none was marked as "claimed by the OS" (all were
marked with a star, but could then be "added" via "scsi
add-single-device ... > /proc/scsi/scsi"). 
This was the actual problem I tried to solve with the patch. Now I don't
see any devices at all in /proc/scsi/scsi.

> What is output during the scan?
qla2300 0000:06:01.0: Found an ISP2312, irq 11, iobase 0xf8806000
qla2300 0000:06:01.0: Configuring PCI space...    
qla2300 0000:06:01.0: Configure NVRAM parameters...
qla2300 0000:06:01.0: Verifying loaded RISC code...                     
qla2300 0000:06:01.0: Waiting for LIP to complete...                            
qla2300 0000:06:01.0: LOOP UP detected (1 Gbps).
qla2300 0000:06:01.0: Topology - (F_Port), Host Loop address 0xffff 
scsi0 : qla2xxx
 QLogic Fibre Channel HBA Driver: 8.00.00b15-k
  QLogic QLA2342 -
qla2300 0000:06:01.0: Found an ISP2312, irq 11, iobase 0xf8806000
  ISP2312: PCI-X (100 MHz) @ 0000:06:01.0 hdma-, host#=0, fw=3.02.30 IPX

qla2300 0000:06:01.1: Found an ISP2312, irq 10, iobase 0xf8854000
qla2300 0000:06:01.1: Configuring PCI space...                                  
qla2300 0000:06:01.1: Configure NVRAM parameters...
qla2300 0000:06:01.1: Verifying loaded RISC code...                 
qla2300 0000:06:01.1: Waiting for LIP to complete...                           
qla2300 0000:06:01.1: LOOP UP detected (1 Gbps).
qla2300 0000:06:01.1: Topology - (F_Port), Host Loop address 0xffff
scsi1 : qla2xxx
 QLogic Fibre Channel HBA Driver: 8.00.00b15-k
  QLogic QLA2342 -
  ISP2312: PCI-X (100 MHz) @ 0000:06:01.1 hdma-, host#=1, fw=3.02.30 IPX

> Can you turn on some scsi logging, and send that?
Sure. I tried scsi_logging_level=... on the kernel command line but it
didn't show anything, did I miss something obvious?
/proc/sys/dev/scsi/logging_level was still zero afterwards.
Cheers,
 -- Guido
> 
> If you have root on scsi, you should shutdown syslogd (though this should
> not generate lots of logging for small amounts of IO it generates some,
> and if you screw up you'll be able to disable the logging), and then 
> capture the console/serial output.
> 
> If root on ide, just leave syslog on and get /var/log/messages output.
> 
> Turn on per-command and scan logging (0x2400 | 0x01c0):
> 
> 	sysctl -w dev.scsi.logging_level=0x25c0
> 
> Set back off afterwards with:
> 
> 	sysctl -w dev.scsi.logging_level=0
> 
> -- Patrick Mansfield

Re: [PATCH] REPORT LUN scan even if no storage is available on LUN 0

[Patrick Mansfield]

On Thu, Jan 13, 2005 at 01:40:32PM +0100, Guido Guenther wrote:

> > Can you turn on some scsi logging, and send that?
> Sure. I tried scsi_logging_level=... on the kernel command line but it
> didn't show anything, did I miss something obvious?
> /proc/sys/dev/scsi/logging_level was still zero afterwards.

It is a sysctl variable, so you can set it after you are booted, per my
other email (and still below), and man sysctl.

If you are building the qlogic driver into the kernel you can still rescan
the LUNs via:

	echo "- - -" > /sys/class/scsi_host/hostN/scan

> > If you have root on scsi, you should shutdown syslogd (though this should
> > not generate lots of logging for small amounts of IO it generates some,
> > and if you screw up you'll be able to disable the logging), and then 
> > capture the console/serial output.
> > 
> > If root on ide, just leave syslog on and get /var/log/messages output.
> > 
> > Turn on per-command and scan logging (0x2400 | 0x01c0):
> > 
> > 	sysctl -w dev.scsi.logging_level=0x25c0
> > 
> > Set back off afterwards with:
> > 
> > 	sysctl -w dev.scsi.logging_level=0
> > 
> > -- Patrick Mansfield

Re: [PATCH] REPORT LUN scan even if no storage is available on LUN 0

[Guido Guenther]

On Thu, Jan 13, 2005 at 04:01:15PM -0800, Patrick Mansfield wrote:
> On Thu, Jan 13, 2005 at 01:40:32PM +0100, Guido Guenther wrote:
> 
> > > Can you turn on some scsi logging, and send that?
> > Sure. I tried scsi_logging_level=... on the kernel command line but it
> > didn't show anything, did I miss something obvious?
> > /proc/sys/dev/scsi/logging_level was still zero afterwards.
> 
> It is a sysctl variable, so you can set it after you are booted, per my
> other email (and still below), and man sysctl.
Yes I saw that, I was just wondering why scsi_logging_level doesn't work
also it's a module option in scsi.c.

> If you are building the qlogic driver into the kernel you can still rescan
> the LUNs via:
> 
> 	echo "- - -" > /sys/class/scsi_host/hostN/scan
O.k. Thanks.
 -- Guido

> > > If you have root on scsi, you should shutdown syslogd (though this should
> > > not generate lots of logging for small amounts of IO it generates some,
> > > and if you screw up you'll be able to disable the logging), and then 
> > > capture the console/serial output.
> > > 
> > > If root on ide, just leave syslog on and get /var/log/messages output.
> > > 
> > > Turn on per-command and scan logging (0x2400 | 0x01c0):
> > > 
> > > 	sysctl -w dev.scsi.logging_level=0x25c0
> > > 
> > > Set back off afterwards with:
> > > 
> > > 	sysctl -w dev.scsi.logging_level=0
> > > 
> > > -- Patrick Mansfield

Re: [PATCH] REPORT LUN scan even if no storage is available on LUN 0

[Patrick Mansfield]

On Fri, Jan 14, 2005 at 10:32:00AM +0100, Guido Guenther wrote:
> On Thu, Jan 13, 2005 at 04:01:15PM -0800, Patrick Mansfield wrote:
> > On Thu, Jan 13, 2005 at 01:40:32PM +0100, Guido Guenther wrote:
> > 
> > > > Can you turn on some scsi logging, and send that?
> > > Sure. I tried scsi_logging_level=... on the kernel command line but it
> > > didn't show anything, did I miss something obvious?
> > > /proc/sys/dev/scsi/logging_level was still zero afterwards.
> > 
> > It is a sysctl variable, so you can set it after you are booted, per my
> > other email (and still below), and man sysctl.
> Yes I saw that, I was just wondering why scsi_logging_level doesn't work
> also it's a module option in scsi.c.

In-kernel module params have to be prefixed by the module name, like:

	scsi_mod.scsi_logging_level=0x2400

AFAIR if the param name is unknown, the kernel outputs a warning.

Note that most (all?) of the other scsi params have the "scsi_" removed,
though the variable name does not, like max_scsi_luns is set via max_luns.

-- Patrick Mansfield

Re: [PATCH] REPORT LUN scan even if no storage is available on LUN 0

[Patrick Mansfield]

On Thu, Jan 13, 2005 at 01:40:32PM +0100, Guido Guenther wrote:

> No. Without any patches we had all the available devices in
> /proc/scsi/scsi but none was marked as "claimed by the OS" (all were
> marked with a star, but could then be "added" via "scsi
> add-single-device ... > /proc/scsi/scsi"). 

Oh ...  the "*" is used in the /proc/scsi/qla2xxx/N files, not
/proc/scsi/scsi.

Is /proc/scsi/qla2xxx/N not showing any LUNs?

If so, that is a different problem.

-- Patrick Mansfield

Re: [PATCH] REPORT LUN scan even if no storage is available on LUN 0

[Guido Guenther]

[-- Attachment #1: Type: text/plain, Size: 2136 bytes --]

On Thu, Jan 13, 2005 at 04:21:34PM -0800, Patrick Mansfield wrote:
> On Thu, Jan 13, 2005 at 01:40:32PM +0100, Guido Guenther wrote:
> 
> > No. Without any patches we had all the available devices in
> > /proc/scsi/scsi but none was marked as "claimed by the OS" (all were
> > marked with a star, but could then be "added" via "scsi
> > add-single-device ... > /proc/scsi/scsi"). 
> 
> Oh ...  the "*" is used in the /proc/scsi/qla2xxx/N files, not
> /proc/scsi/scsi.
You're absolutely right. The above should read:

Without any patches we had all the available devices in
/proc/scsi/qla2xxx/N but none was marked as "claimed by the OS" (all
were marked with a star, but could then be "added" via "scsi
add-single-device ... > /proc/scsi/scsi"). 

Sorry for the confusion. 

This is the target that has all the devices:
# echo "0 0 -" > /sys/class/scsi_host/host0/scan
scsi_scan_host_selected: <0:0:0:4294967295>
scsi scan: INQUIRY to host 0 channel 0 id 0 lun 0
scsi <0:0:0:0> send                  scsi0 : destination target 0, lun 0
        command = Inquiry 00 00 00 24 00
scsi <0:0:0:0> done SUCCESS        0 scsi0 : destination target 0, lun 0
        command = Inquiry 00 00 00 24 00
scsi scan: 1st INQUIRY successful with code 0x0
scsi <0:0:0:0> send                  scsi0 : destination target 0, lun 0
        command = Inquiry 00 00 00 95 00
scsi <0:0:0:0> done SUCCESS        0 scsi0 : destination target 0, lun 0
        command = Inquiry 00 00 00 95 00
scsi scan: 2nd INQUIRY successful with code 0x0
scsi scan: peripheral qualifier of 3, no device added
scsi scan: Sequential scan of host 0 channel 0 id 0

While this is an empty one:
# echo "0 1 -" > /sys/class/scsi_host/host0/scan
scsi_scan_host_selected: <0:0:1:4294967295>
scsi scan: INQUIRY to host 0 channel 0 id 1 lun 0
scsi <0:0:1:0> send                  scsi0 : destination target 1, lun 0
        command = Inquiry 00 00 00 24 00
scsi <0:0:1:0> done SUCCESS    10000 scsi0 : destination target 1, lun 0
        command = Inquiry 00 00 00 24 00
scsi scan: 1st INQUIRY failed with code 0x10000

Cheers,
 -- Guido

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Re: [PATCH] REPORT LUN scan even if no storage is available on LUN 0

[Patrick Mansfield]

On Fri, Jan 14, 2005 at 02:26:23PM +0100, Guido Guenther wrote:
> On Thu, Jan 13, 2005 at 04:21:34PM -0800, Patrick Mansfield wrote:

> This is the target that has all the devices:
> # echo "0 0 -" > /sys/class/scsi_host/host0/scan
> scsi_scan_host_selected: <0:0:0:4294967295>
> scsi scan: INQUIRY to host 0 channel 0 id 0 lun 0
> scsi <0:0:0:0> send                  scsi0 : destination target 0, lun 0
>         command = Inquiry 00 00 00 24 00
> scsi <0:0:0:0> done SUCCESS        0 scsi0 : destination target 0, lun 0
>         command = Inquiry 00 00 00 24 00
> scsi scan: 1st INQUIRY successful with code 0x0
> scsi <0:0:0:0> send                  scsi0 : destination target 0, lun 0
>         command = Inquiry 00 00 00 95 00
> scsi <0:0:0:0> done SUCCESS        0 scsi0 : destination target 0, lun 0
>         command = Inquiry 00 00 00 95 00
> scsi scan: 2nd INQUIRY successful with code 0x0
> scsi scan: peripheral qualifier of 3, no device added
> scsi scan: Sequential scan of host 0 channel 0 id 0
> 
> While this is an empty one:
> # echo "0 1 -" > /sys/class/scsi_host/host0/scan
> scsi_scan_host_selected: <0:0:1:4294967295>
> scsi scan: INQUIRY to host 0 channel 0 id 1 lun 0
> scsi <0:0:1:0> send                  scsi0 : destination target 1, lun 0
>         command = Inquiry 00 00 00 24 00
> scsi <0:0:1:0> done SUCCESS    10000 scsi0 : destination target 1, lun 0
>         command = Inquiry 00 00 00 24 00
> scsi scan: 1st INQUIRY failed with code 0x10000

Your device must be reporting as SCSI-2, that makes sense, since you
needed other bflags set. The logging should really dump the scsi_level.
You need to add an entry to the devinfo list to force a REPORT LUNs scan.

I don't know why it is not already in scsi_devinfo.c, AFAIR REPORT LUNs
has always worked with EMC, and should be in its devinfo flag (and
probably the only devinfo flag, since sparse, largelun and forcelun are
meaningless for a REPORT LUN scan).

module params can be used, but /proc/scsi/device_info is easiest. Make
sure I have the correct vendor:model, this should work:

	echo "EMC:SYMMETRIX:0x20000" > /proc/scsi/device_info

BLIST_REPORTLUN2 is 0x20000.

-- Patrick Mansfield