From: Hendrik Brueckner <brueckner@redhat.com>
Date: Wed, 12 May 2010 12:20:52 -0400
Subject: [s390] smsgiucv: add missing check for z/VM
Message-id: <20100512122051.GC18564@redhat.com>
Patchwork-id: 25017
O-Subject: [RHEL5.6 PATCH 1/1] [s390x] smsgiucv: missing check for z/VM
Bugzilla: 590737
RH-Acked-by: Pete Zaitcev <zaitcev@redhat.com>

Description
-----------
Loading the smsgiucv module on LPAR causes the driver core
and list debugging code to generate several error messages.

smsgiucv is a driver that relies on IUCV to work properly.
If IUCV and smsgiucv are compiled into the kernel and run
on an LPAR the following scenario happens:  IUCV is
initialized early as a subsystem.  It checks for z/VM and
returns with EPROTONOTSUPPORT.  Later smsgiucv tries to run
driver_register with iucv_bus as bus.  As this bus is not
initialized the errors are reported.

smsg_init has to check for running on z/VM.

Bugzilla
--------
BZ 590737
https://bugzilla.redhat.com/show_bug.cgi?id=590737

Upstream status of the patch
----------------------------
The patch is upstream as of kernel version 2.6.24
http://git.kernel.org/?p=linux/kernel/git/torvalds/linux-2.6.git;a=commitdiff;h=0fc3ddd67a6781238b038165d9dd8c1f9ba81111

Test status
-----------
The patch has been tested and fixes the problem.
The fix has been verified by the IBM test department.


diff --git a/drivers/s390/net/smsgiucv.c b/drivers/s390/net/smsgiucv.c
index 3ccca58..47bb47b 100644
--- a/drivers/s390/net/smsgiucv.c
+++ b/drivers/s390/net/smsgiucv.c
@@ -148,6 +148,10 @@ static int __init smsg_init(void)
 {
 	int rc;
 
+	if (!MACHINE_IS_VM) {
+		rc = -EPROTONOSUPPORT;
+		goto out;
+	}
 	rc = driver_register(&smsg_driver);
 	if (rc != 0)
 		goto out;