From: Hans-Joachim Picht <hpicht@redhat.com>
Date: Tue, 30 Oct 2007 17:12:12 +0100
Subject: [s390] panic with lcs interface as dhcp server
Message-id: 20071030161212.GK6604@redhat.com
O-Subject: [RHEL5.2 PATCH] s390 Kernel panic with lcs interface as dhcp server
Bugzilla: 350861

Problem:
=========

When a dhcp server is started using a lcs interface , the dhcp server crashes and
the  lcs interface goes down and later on leads to a kernel panic.
Lcs detects  (lcs_irq) channel and device failures on the lcs device which
starts lcs_recovery.

Bugzilla
=========

BZ 350861
https://bugzilla.redhat.com/show_bug.cgi?id=350861

Upstream status of the patch:
=============================

Patch has been submitted for upstream integraton:
http://lkml.org/lkml/2007/10/5/188

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

Please ACK.

With best regards,

Hans

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

diff --git a/drivers/s390/net/lcs.c b/drivers/s390/net/lcs.c
index 16ac68c..2c8347b 100644
--- a/drivers/s390/net/lcs.c
+++ b/drivers/s390/net/lcs.c
@@ -1397,11 +1397,13 @@ lcs_irq(struct ccw_device *cdev, unsigned long intparm, struct irb *irb)
 	if (rc || (dstat & DEV_STAT_UNIT_EXCEP)) {
 		PRINT_WARN("check on device %s, dstat=0x%X, cstat=0x%X \n",
 			    cdev->dev.bus_id, dstat, cstat);
-		if (rc) {
-			lcs_schedule_recovery(card);
-			wake_up(&card->wait_q);
-			return;
-		}
+		if (rc)
+			channel->state = CH_STATE_ERROR;
+	}
+	if (channel->state == CH_STATE_ERROR) {
+		lcs_schedule_recovery(card);
+		wake_up(&card->wait_q);
+		return;
 	}
 	/* How far in the ccw chain have we processed? */
 	if ((channel->state != CH_STATE_INIT) &&
@@ -1707,6 +1709,8 @@ lcs_stopcard(struct lcs_card *card)
 
 	if (card->read.state != CH_STATE_STOPPED &&
 	    card->write.state != CH_STATE_STOPPED &&
+	    card->read.state != CH_STATE_ERROR &&
+	    card->write.state != CH_STATE_ERROR &&
 	    card->state == DEV_STATE_UP) {
 		lcs_clear_multicast_list(card);
 		rc = lcs_send_stoplan(card,LCS_INITIATOR_TCPIP);
diff --git a/drivers/s390/net/lcs.h b/drivers/s390/net/lcs.h
index 9314393..383694a 100644
--- a/drivers/s390/net/lcs.h
+++ b/drivers/s390/net/lcs.h
@@ -143,6 +143,7 @@ enum lcs_channel_states {
 	CH_STATE_RUNNING,
 	CH_STATE_SUSPENDED,
 	CH_STATE_CLEARED,
+	CH_STATE_ERROR,
 };
 
 /**