[PATCH AUTOSEL for 4.4 151/167] s390/dasd: fix hanging safe offline

Sasha Levin
2018-03-19T16:11:27Z

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_device *device,
{
int mask = ~(DASD_STOPPED_DC_WAIT | DASD_UNRESUMED_PM);

- 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) {
--
2.14.1