From: Jan Glauber <jglauber@redhat.com>
Date: Sat, 12 Jan 2008 15:20:32 +0100
Subject: [s390] zfcp: error messages when LUN 0 is present
Message-id: 1200147632.6182.49.camel@localhost.localdomain
O-Subject: Re: [RHEL5 U2 PATCH 3/14] s390 - zfcp: Error messages when LUN 0 is present
Bugzilla: 354811

Description
============

When the FCP LUN 0 is present, the kernel messages can
contain lots of messages like "scsi: host 0 channel 0
id 1 lun2 has a LUN larger than allowed by the host
adapter".

The FC transport class triggers a scan for units. This
triggers a REPORT LUNS command. When the units should
be added to zfcp, this fails with the above message.
With the current design of zfcp, this scan should
never happen, since the units are managed by zfcp.

The problem is fixed by introducig a flag that prevents the
scan from the FC transport class.

Bugzilla
=========

BZ 354811
https://bugzilla.redhat.com/show_bug.cgi?id=354811

Upstream status of the patch:
=============================
Problem fixed upstream in
http://git.kernel.org/?p=linux/kernel/git/jejb/scsi-misc-2.6.git;a=commit;h=cb7ec97c94520c78a52eff201cade337319d07e8

Test status:
============
Kernel with patch was built and successfully tested

Here is the new version of the patch. The changes are:
- moved the extern to a header file
- using an int for the flag instead of unsigned long

The patch was also reviewed by Christof Schmitt.

Please apply,
Jan

jglauber@redhat.com
jang@de.ibm.com

Acked-by: Pete Zaitcev <zaitcev@redhat.com>

diff --git a/drivers/s390/scsi/zfcp_aux.c b/drivers/s390/scsi/zfcp_aux.c
index 4b167de..d4d802c 100644
--- a/drivers/s390/scsi/zfcp_aux.c
+++ b/drivers/s390/scsi/zfcp_aux.c
@@ -320,6 +320,8 @@ zfcp_module_init(void)
 	zfcp_transport_template = fc_attach_transport(&zfcp_transport_functions);
 	if (!zfcp_transport_template)
 		return -ENODEV;
+	/* disable transport scan */
+	set_fc_internal_target_scan(zfcp_transport_template);
 
 	retval = misc_register(&zfcp_cfdc_misc);
 	if (retval != 0) {
diff --git a/drivers/s390/scsi/zfcp_ext.h b/drivers/s390/scsi/zfcp_ext.h
index f6ba8dc..6a559d5 100644
--- a/drivers/s390/scsi/zfcp_ext.h
+++ b/drivers/s390/scsi/zfcp_ext.h
@@ -193,4 +193,6 @@ extern struct zfcp_fsf_req *zfcp_reqlist_ismember(struct zfcp_adapter *,
 						  unsigned long);
 extern int zfcp_reqlist_isempty(struct zfcp_adapter *);
 
+extern void set_fc_internal_target_scan(struct scsi_transport_template *t);
+
 #endif	/* ZFCP_EXT_H */
diff --git a/drivers/scsi/scsi_transport_fc.c b/drivers/scsi/scsi_transport_fc.c
index cf8cdd6..d0962c6 100644
--- a/drivers/scsi/scsi_transport_fc.c
+++ b/drivers/scsi/scsi_transport_fc.c
@@ -279,10 +279,19 @@ struct fc_internal {
 	struct transport_container rport_attr_cont;
 	struct class_device_attribute private_rport_attrs[FC_RPORT_NUM_ATTRS];
 	struct class_device_attribute *rport_attrs[FC_RPORT_NUM_ATTRS + 1];
+
+	/* needed for kabi workaround for zfcp driver */
+	int disable_target_scan;
 };
 
 #define to_fc_internal(tmpl)	container_of(tmpl, struct fc_internal, t)
 
+void set_fc_internal_target_scan(struct scsi_transport_template *t)
+{
+	to_fc_internal(t)->disable_target_scan = 1;
+}
+EXPORT_SYMBOL_GPL(set_fc_internal_target_scan);
+
 static int fc_target_setup(struct transport_container *tc, struct device *dev,
 			   struct class_device *cdev)
 {
@@ -2422,10 +2431,12 @@ fc_scsi_scan_rport(void *data)
 {
 	struct fc_rport *rport = (struct fc_rport *)data;
 	struct Scsi_Host *shost = rport_to_shost(rport);
+	struct fc_internal *i = to_fc_internal(shost->transportt);
 	unsigned long flags;
 
 	if ((rport->port_state == FC_PORTSTATE_ONLINE) &&
-	    (rport->roles & FC_RPORT_ROLE_FCP_TARGET)) {
+	    (rport->roles & FC_RPORT_ROLE_FCP_TARGET) &&
+	    !(i->disable_target_scan)) {
 		scsi_scan_target(&rport->dev, rport->channel,
 			rport->scsi_target_id, SCAN_WILD_CARD, 1);
 	}