linux-stable/drivers/s390
Steffen Maier a93cd9137f scsi: zfcp: fix scsi_eh host reset with port_forced ERP for non-NPIV FCP devices
commit 242ec14551 upstream.

Suppose more than one non-NPIV FCP device is active on the same channel.
Send I/O to storage and have some of the pending I/O run into a SCSI
command timeout, e.g. due to bit errors on the fibre. Now the error
situation stops. However, we saw FCP requests continue to timeout in the
channel. The abort will be successful, but the subsequent TUR fails.
Scsi_eh starts. The LUN reset fails. The target reset fails.  The host
reset only did an FCP device recovery. However, for non-NPIV FCP devices,
this does not close and reopen ports on the SAN-side if other non-NPIV FCP
device(s) share the same open ports.

In order to resolve the continuing FCP request timeouts, we need to
explicitly close and reopen ports on the SAN-side.

This was missing since the beginning of zfcp in v2.6.0 history commit
ea127f975424 ("[PATCH] s390 (7/7): zfcp host adapter.").

Note: The FSF requests for forced port reopen could run into FSF request
timeouts due to other reasons. This would trigger an internal FCP device
recovery. Pending forced port reopen recoveries would get dismissed. So
some ports might not get fully reopened during this host reset handler.
However, subsequent I/O would trigger the above described escalation and
eventually all ports would be forced reopen to resolve any continuing FCP
request timeouts due to earlier bit errors.

Signed-off-by: Steffen Maier <maier@linux.ibm.com>
Fixes: 1da177e4c3 ("Linux-2.6.12-rc2")
Cc: <stable@vger.kernel.org> #3.0+
Reviewed-by: Jens Remus <jremus@linux.ibm.com>
Reviewed-by: Benjamin Block <bblock@linux.ibm.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-04-03 06:26:24 +02:00
..
block s390/dasd: fix using offset into zero size array error 2019-03-23 20:09:42 +01:00
char s390/smp: fix CPU hotplug deadlock with CPU rescan 2019-01-31 08:14:35 +01:00
cio vfio: ccw: only free cp on final interrupt 2019-04-03 06:26:21 +02:00
crypto s390/zcrypt: fix specification exception on z196 during ap probe 2019-02-20 10:25:48 +01:00
net s390/qeth: cancel close_dev work before removing a card 2019-03-13 14:02:37 -07:00
scsi scsi: zfcp: fix scsi_eh host reset with port_forced ERP for non-NPIV FCP devices 2019-04-03 06:26:24 +02:00
virtio s390/virtio: handle find on invalid queue gracefully 2019-03-23 20:09:58 +01:00
Makefile kbuild: rename built-in.o to built-in.a 2018-03-26 02:01:19 +09:00