From: Jan Glauber <jglauber@redhat.com>
Subject: [RHEL5.1 PATCH] prevent dasd from flooding the console
Date: Tue, 05 Jun 2007 11:49:39 +0000
Bugzilla: 229590
Message-Id: <1181044179.5323.10.camel@localhost.localdomain>
Changelog: [dasd] prevent dasd from flooding the console


BZ 229590

In case of a cable pull the console is flooded with retry messages by
the dasd driver and the system is not responding anymore. The problem
is the handling of failed termination requests. In case a request timed
out and termination did not work a message was printed every 100ms.

Now we use a 5s delay per retry and generate a more precise message.

Patch is tested by IBM and upstream.

Please ack,
Jan

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

---

diff -Naurp linux-2.6.18.s390x/drivers/s390/block/dasd.c linux-2.6.18.s390x-new/drivers/s390/block/dasd.c
--- linux-2.6.18.s390x/drivers/s390/block/dasd.c	2006-09-20 05:42:06.000000000 +0200
+++ linux-2.6.18.s390x-new/drivers/s390/block/dasd.c	2007-02-09 17:44:53.000000000 +0100
@@ -1263,15 +1263,21 @@ __dasd_check_expire(struct dasd_device *
 	if (list_empty(&device->ccw_queue))
 		return;
 	cqr = list_entry(device->ccw_queue.next, struct dasd_ccw_req, list);
-	if (cqr->status == DASD_CQR_IN_IO && cqr->expires != 0) {
-		if (time_after_eq(jiffies, cqr->expires + cqr->starttime)) {
+	if ((cqr->status == DASD_CQR_IN_IO && cqr->expires != 0) &&
+	    (time_after_eq(jiffies, cqr->expires + cqr->starttime))) {
+		if (device->discipline->term_IO(cqr) != 0) {
+			/* Hmpf, try again in 5 sec */
+			dasd_set_timer(device, 5*HZ);
+			DEV_MESSAGE(KERN_ERR, device,
+				    "internal error - timeout (%is) expired "
+				    "for cqr %p, termination failed, "
+				    "retrying in 5s",
+				    (cqr->expires/HZ), cqr);
+		} else {
 			DEV_MESSAGE(KERN_ERR, device,
 				    "internal error - timeout (%is) expired "
 				    "for cqr %p (%i retries left)",
 				    (cqr->expires/HZ), cqr, cqr->retries);
-			if (device->discipline->term_IO(cqr) != 0)
-				/* Hmpf, try again in 1/10 sec */
-				dasd_set_timer(device, 10);
 		}
 	}
 }