Reenabled linux-xen and xen-image build

[people/pmueller/ipfire-2.x.git] / src / patches / suse-2.6.27.25 / patches.arch / s390-12-12-zfcp_wka_wait_refcount.patch

From: Gerald Schaefer <geraldsc@de.ibm.com>
Subject: zfcp: deadlock between scheduled task, ERP and scan_work
References: bnc#487755,LTC#52845 

Symptom:     I/O stalls due to a pending ERP action.
Problem:     Under certain timing constraints a deadlock can prevent
             the ERP to finish. The ERP is trying to force the wka
             port offline waiting for the scheduled work to finish.
             The scheduled work is waiting for the refcount to 
             turn zero and another task is waiting for the ERP to 
             finish before descrementing the refcounter. ->deadlock
Solution:    Don't wait for the refcount to turn zero. If required
             the wka port offline function is called again later.

Acked-by: John Jolly <jjolly@suse.de>

---
 drivers/s390/scsi/zfcp_fc.c |    3 ---
 1 file changed, 3 deletions(-)

Index: linux-sles11/drivers/s390/scsi/zfcp_fc.c
===================================================================
--- linux-sles11.orig/drivers/s390/scsi/zfcp_fc.c
+++ linux-sles11/drivers/s390/scsi/zfcp_fc.c
@@ -75,9 +75,6 @@ static void zfcp_wka_port_offline(struct
 	struct zfcp_wka_port *wka_port =
 			container_of(dw, struct zfcp_wka_port, work);
 
-	wait_event(wka_port->completion_wq,
-			atomic_read(&wka_port->refcount) == 0);
-
 	mutex_lock(&wka_port->mutex);
 	if ((atomic_read(&wka_port->refcount) != 0) ||
 	    (wka_port->status != ZFCP_WKA_PORT_ONLINE))