s390/dasd: fix hanging safe offline

[ 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>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/s390/block/dasd.c b/drivers/s390/block/dasd.c
index e7a6f12226425ef0f2a0469e72edee33c225dccf..b76a85d14ef0c64b389e9448280af220a130aeb4 100644 (file)
--- 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) {