[PATCH 3.16 064/366] scsi: zfcp: fix missing REC trigger trace on terminate_rport_io for ERP_FAILED

Ben Hutchings
2018-11-11T20:14:35Z

From: Steffen Maier <maier@linux.ibm.com>

commit d70aab55924b44f213fec2b900b095430b33eec6 upstream.

For problem determination we always want to see when we were invoked on the
terminate_rport_io callback whether we perform something or not.

Temporal event sequence of interest with a long fast_io_fail_tmo of 27 sec:

loose remote port

t workqueue
[s] zfcp_q_<dev> IRQ zfcperp<dev>

=== ================== =================== ============================

0 recv RSCN
q p.test_link_work
block rport
start fast_io_fail_tmo
send ADISC ELS
4 recv ADISC fail
block zfcp_port
port forced reopen
send open port
12 recv open port fail
q p.gid_pn_work
zfcp_erp_wakeup
(zfcp_erp_wait would return)
GID_PN fail

Before this point, we got a SCSI trace with tag "sctrpi1" on fast_io_fail,
e.g. with the typical 5 sec setting.

port.status |= ERP_FAILED

If fast_io_fail_tmo triggers after this point, we missed a SCSI trace.

workqueue
fc_dl_<host>
==================
27 fc_timeout_fail_rport_io
fc_terminate_rport_io
zfcp_scsi_terminate_rport_io
zfcp_erp_port_forced_reopen
_zfcp_erp_port_forced_reopen
if (port.status & ERP_FAILED)
return;

Therefore, write a trace before above early return.

Example trace record formatted with zfcpdbf from s390-tools:

Timestamp : ...
Area : REC
Subarea : 00
Level : 1
Exception : -
CPU ID : ..
Caller : 0x...
Record ID : 1 ZFCP_DBF_REC_TRIG
Tag : sctrpi1 SCSI terminate rport I/O
LUN : 0xffffffffffffffff none (invalid)
WWPN : 0x<wwpn>
D_ID : 0x<n_port_id>
Adapter status : 0x...
Port status : 0x...
LUN status : 0x00000000 none (invalid)
Ready count : 0x...
Running count : 0x...
ERP want : 0x03 ZFCP_ERP_ACTION_REOPEN_PORT_FORCED
ERP need : 0xe0 ZFCP_ERP_ACTION_FAILED

Signed-off-by: Steffen Maier <maier@linux.ibm.com>
Reviewed-by: Benjamin Block <bblock@linux.ibm.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
---
drivers/s390/scsi/zfcp_erp.c | 13 +++++++++++--
1 file changed, 11 insertions(+), 2 deletions(-)

--- a/drivers/s390/scsi/zfcp_erp.c
+++ b/drivers/s390/scsi/zfcp_erp.c
@@ -41,9 +41,13 @@ enum zfcp_erp_steps {
* @ZFCP_ERP_ACTION_REOPEN_PORT_FORCED: Forced port recovery.
* @ZFCP_ERP_ACTION_REOPEN_ADAPTER: Adapter recovery.
* @ZFCP_ERP_ACTION_NONE: Eyecatcher pseudo flag to bitwise or-combine with
- * either of the other enum values.
+ * either of the first four enum values.
* Used to indicate that an ERP action could not be
* set up despite a detected need for some recovery.
+ * @ZFCP_ERP_ACTION_FAILED: Eyecatcher pseudo flag to bitwise or-combine with
+ * either of the first four enum values.
+ * Used to indicate that ERP not needed because
+ * the object has ZFCP_STATUS_COMMON_ERP_FAILED.
*/
enum zfcp_erp_act_type {
ZFCP_ERP_ACTION_REOPEN_LUN = 1,
@@ -51,6 +55,7 @@ enum zfcp_erp_act_type {
ZFCP_ERP_ACTION_REOPEN_PORT_FORCED = 3,
ZFCP_ERP_ACTION_REOPEN_ADAPTER = 4,
ZFCP_ERP_ACTION_NONE = 0xc0,
+ ZFCP_ERP_ACTION_FAILED = 0xe0,
};

enum zfcp_erp_act_state {
@@ -378,8 +383,12 @@ static void _zfcp_erp_port_forced_reopen
zfcp_erp_port_block(port, clear);
zfcp_scsi_schedule_rport_block(port);

- if (atomic_read(&port->status) & ZFCP_STATUS_COMMON_ERP_FAILED)
+ if (atomic_read(&port->status) & ZFCP_STATUS_COMMON_ERP_FAILED) {
+ zfcp_dbf_rec_trig(id, port->adapter, port, NULL,
+ ZFCP_ERP_ACTION_REOPEN_PORT_FORCED,
+ ZFCP_ERP_ACTION_FAILED);
return;
+ }

zfcp_erp_action_enqueue(ZFCP_ERP_ACTION_REOPEN_PORT_FORCED,
port->adapter, port, NULL, id, 0);