Received-SPF: pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) client-ip=209.132.180.67;
From:   Sasha Levin <Alexander.Levin@microsoft.com>
To:     "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
        "stable@vger.kernel.org" <stable@vger.kernel.org>
CC:     Stefan Haberland <sth@linux.vnet.ibm.com>,
        Martin Schwidefsky <schwidefsky@de.ibm.com>,
        Sasha Levin <Alexander.Levin@microsoft.com>
Subject: [PATCH AUTOSEL for 4.4 151/167] s390/dasd: fix hanging safe offline
Thread-Topic: [PATCH AUTOSEL for 4.4 151/167] s390/dasd: fix hanging safe
 offline
Thread-Index: AQHTv5yGDn6mHYfLTkS4WDc/5ttdmw==
Date:   Mon, 19 Mar 2018 16:08:32 +0000
Message-ID: <20180319160513.16384-151-alexander.levin@microsoft.com>
References: <20180319160513.16384-1-alexander.levin@microsoft.com>
In-Reply-To: <20180319160513.16384-1-alexander.levin@microsoft.com>
Accept-Language: en-US
Content-Language: en-US
received-spf: None (protection.outlook.com: microsoft.com does not designate
 permitted sender hosts)
spamdiagnosticoutput: 1:99
spamdiagnosticmetadata: NSPM
Content-Type: text/plain; charset="iso-8859-1"
Content-Transfer-Encoding: quoted-printable
MIME-Version: 1.0
X-MS-Exchange-CrossTenant-Network-Message-Id: e4096644-4de3-4af1-b0a9-08d58db40dd2
X-MS-Exchange-CrossTenant-originalarrivaltime: 19 Mar 2018 16:08:32.0418
 (UTC)
X-MS-Exchange-CrossTenant-fromentityheader: Hosted
X-MS-Exchange-CrossTenant-id: 72f988bf-86f1-41af-91ab-2d7cd011db47
X-MS-Exchange-Transport-CrossTenantHeadersStamped: DM5PR2101MB0984
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk
List-ID: <linux-kernel.vger.kernel.org>
X-Mailing-List: linux-kernel@vger.kernel.org

From: Stefan Haberland <sth@linux.vnet.ibm.com>

[ Upstream commit e8ac01555d9e464249e8bb122337d6d6e5589ccc ]

The safe offline processing may hang forever because it waits for I/O
which can not be started because of the offline flag that prevents new
I/O from being started.

Allow I/O to be started during safe offline processing because in this
special case we take care that the queues are empty before throwing away
the device.

Signed-off-by: Stefan Haberland <sth@linux.vnet.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Signed-off-by: Sasha Levin <alexander.levin@microsoft.com>
---
 drivers/s390/block/dasd.c | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/drivers/s390/block/dasd.c b/drivers/s390/block/dasd.c
index e7a6f1222642..b76a85d14ef0 100644
--- a/drivers/s390/block/dasd.c
+++ b/drivers/s390/block/dasd.c
@@ -1881,8 +1881,12 @@ static int __dasd_device_is_unusable(struct dasd_dev=
ice *device,
 {
 	int mask =3D ~(DASD_STOPPED_DC_WAIT | DASD_UNRESUMED_PM);
=20
-	if (test_bit(DASD_FLAG_OFFLINE, &device->flags)) {
-		/* dasd is being set offline. */
+	if (test_bit(DASD_FLAG_OFFLINE, &device->flags) &&
+	    !test_bit(DASD_FLAG_SAFE_OFFLINE_RUNNING, &device->flags)) {
+		/*
+		 * dasd is being set offline
+		 * but it is no safe offline where we have to allow I/O
+		 */
 		return 1;
 	}
 	if (device->stopped) {
--=20
2.14.1