From: Jan Glauber <jglauber@redhat.com>
Subject: [RHEL5.1 PATCH] qdio: system hang with zfcp in case of adapter 	problems
Date: Fri, 15 Jun 2007 13:17:55 +0000
Bugzilla: 241298
Message-Id: <1181913475.5508.43.camel@localhost.localdomain>
Changelog: [s390] qdio: system hang with zfcp in case of adapter problems


BZ 241298

If the qdio-QEBSM-support is active and setting of qdio-buffers
fails with an error in the ccq value, none of the qdio
buffers might be set, which causes an endless loop in the qdio-code.

Solution: Stop trying to set qdio-buffers, if an attempt returns 
with 0 as the number of processed buffers.

Patch is upstream and tested by IBM.

Please ack,
Jan

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

Index: linux-rhel5/drivers/s390/cio/qdio.c
===================================================================
--- linux-rhel5.orig/drivers/s390/cio/qdio.c	2007-05-08 17:39:55.000000000 +0200
+++ linux-rhel5/drivers/s390/cio/qdio.c	2007-05-08 17:40:00.000000000 +0200
@@ -3354,10 +3354,15 @@ qdio_do_qdio_fill_input(struct qdio_q *q
 			unsigned int count, struct qdio_buffer *buffers)
 {
 	struct qdio_irq *irq = (struct qdio_irq *) q->irq_ptr;
+	int tmp = 0;
+
 	qidx &= (QDIO_MAX_BUFFERS_PER_Q - 1);
 	if (irq->is_qebsm) {
-		while (count)
-			set_slsb(q, &qidx, SLSB_CU_INPUT_EMPTY, &count);
+		while (count) {
+			tmp = set_slsb(q, &qidx, SLSB_CU_INPUT_EMPTY, &count);
+			if (!tmp)
+				return;
+		}
 		return;
 	}
 	for (;;) {
@@ -3373,11 +3378,15 @@ qdio_do_qdio_fill_output(struct qdio_q *
 			 unsigned int count, struct qdio_buffer *buffers)
 {
 	struct qdio_irq *irq = (struct qdio_irq *) q->irq_ptr;
+	int tmp = 0;
 
 	qidx &= (QDIO_MAX_BUFFERS_PER_Q - 1);
 	if (irq->is_qebsm) {
-		while (count)
-			set_slsb(q, &qidx, SLSB_CU_OUTPUT_PRIMED, &count);
+		while (count) {
+			tmp = set_slsb(q, &qidx, SLSB_CU_OUTPUT_PRIMED, &count);
+			if (!tmp)
+				return;
+		}
 		return;
 	}