From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mx0a-001b2d01.pphosted.com ([148.163.156.1]:39402 "EHLO mx0a-001b2d01.pphosted.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728217AbfHALGh (ORCPT ); Thu, 1 Aug 2019 07:06:37 -0400 Received: from pps.filterd (m0098394.ppops.net [127.0.0.1]) by mx0a-001b2d01.pphosted.com (8.16.0.27/8.16.0.27) with SMTP id x71B31Li068776 for ; Thu, 1 Aug 2019 07:06:36 -0400 Received: from e06smtp05.uk.ibm.com (e06smtp05.uk.ibm.com [195.75.94.101]) by mx0a-001b2d01.pphosted.com with ESMTP id 2u3vnmpae3-1 (version=TLSv1.2 cipher=AES256-GCM-SHA384 bits=256 verify=NOT) for ; Thu, 01 Aug 2019 07:06:36 -0400 Received: from localhost by e06smtp05.uk.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted for from ; Thu, 1 Aug 2019 12:06:34 +0100 From: Stefan Haberland Subject: [PATCH 1/1] s390/dasd: fix endless loop after read unit address configuration Date: Thu, 1 Aug 2019 13:06:30 +0200 In-Reply-To: <20190801110630.82432-1-sth@linux.ibm.com> References: <20190801110630.82432-1-sth@linux.ibm.com> Message-Id: <20190801110630.82432-2-sth@linux.ibm.com> Sender: linux-s390-owner@vger.kernel.org List-ID: To: axboe@kernel.dk Cc: linux-block@vger.kernel.org, linux-s390@vger.kernel.org, hoeppner@linux.ibm.com, heiko.carstens@de.ibm.com, borntraeger@de.ibm.com, gor@linux.ibm.com After getting a storage server event that causes the DASD device driver to update its unit address configuration during a device shutdown there is the possibility of an endless loop in the device driver. In the system log there will be ongoing DASD error messages with RC: -19. The reason is that the loop starting the ruac request only terminates when the retry counter is decreased to 0. But in the sleep_on function there are early exit paths that do not decrease the retry counter. Prevent an endless loop by handling those cases separately. Remove the unnecessary do..while loop since the sleep_on function takes care of retries by itself. Fixes: 8e09f21574ea ("[S390] dasd: add hyper PAV support to DASD device driver, part 1") Cc: stable@vger.kernel.org # 2.6.25+ Signed-off-by: Stefan Haberland Reviewed-by: Jan Hoeppner --- drivers/s390/block/dasd_alias.c | 22 ++++++++++++++++------ 1 file changed, 16 insertions(+), 6 deletions(-) diff --git a/drivers/s390/block/dasd_alias.c b/drivers/s390/block/dasd_alias.c index b9ce93e9df89..99f86612f775 100644 --- a/drivers/s390/block/dasd_alias.c +++ b/drivers/s390/block/dasd_alias.c @@ -383,6 +383,20 @@ suborder_not_supported(struct dasd_ccw_req *cqr) char msg_format; char msg_no; + /* + * intrc values ENODEV, ENOLINK and EPERM + * will be optained from sleep_on to indicate that no + * IO operation can be started + */ + if (cqr->intrc == -ENODEV) + return 1; + + if (cqr->intrc == -ENOLINK) + return 1; + + if (cqr->intrc == -EPERM) + return 1; + sense = dasd_get_sense(&cqr->irb); if (!sense) return 0; @@ -447,12 +461,8 @@ static int read_unit_address_configuration(struct dasd_device *device, lcu->flags &= ~NEED_UAC_UPDATE; spin_unlock_irqrestore(&lcu->lock, flags); - do { - rc = dasd_sleep_on(cqr); - if (rc && suborder_not_supported(cqr)) - return -EOPNOTSUPP; - } while (rc && (cqr->retries > 0)); - if (rc) { + rc = dasd_sleep_on(cqr); + if (rc && !suborder_not_supported(cqr)) { spin_lock_irqsave(&lcu->lock, flags); lcu->flags |= NEED_UAC_UPDATE; spin_unlock_irqrestore(&lcu->lock, flags); -- 2.17.1