[PATCH 02/25] zfcp: fix missing SCSI trace for retry of abort / scsi_eh TMF

[Steffen Maier <maier@linux.ibm.com>]

We already have a SCSI trace for the end of abort and scsi_eh TMF. Due to
zfcp_erp_wait() and fc_block_scsi_eh() time can pass between the
start of our eh callback and an actual send/recv of an abort / TMF request.
In order to see the temporal sequence including any abort / TMF send
retries, add a trace before the above two blocking functions.
This supports problem determination with scsi_eh and parallel zfcp ERP.

No need to explicitly trace the beginning of our eh callback, since we
typically can send an abort / TMF and see its HBA response (in the worst
case, it's a pseudo response on dismiss all of adapter recovery, e.g. due
to an FSF request timeout [fsrth_1] of the abort / TMF). If we cannot send,
we now get a trace record for the first "abrt_wt" or "[lt]r_wait" which
denotes almost the beginning of the callback.

No need to explicitly trace the wakeup after the above two blocking
functions because the next retry loop causes another trace in any case
and that is sufficient.

Example trace records formatted with zfcpdbf from s390-tools:

Timestamp      : ...
Area           : SCSI
Subarea        : 00
Level          : 1
Exception      : -
CPU ID         : ..
Caller         : 0x...
Record ID      : 1
Tag            : abrt_wt        abort, before zfcp_erp_wait()
Request ID     : 0x0000000000000000                     none (invalid)
SCSI ID        : 0x<scsi_id>
SCSI LUN       : 0x<scsi_lun>
SCSI LUN high  : 0x<scsi_lun_high>
SCSI result    : 0x<scsi_result_of_cmd_to_be_aborted>
SCSI retries   : 0x<retries_of_cmd_to_be_aborted>
SCSI allowed   : 0x<allowed_retries_of_cmd_to_be_aborted>
SCSI scribble  : 0x<req_id_of_cmd_to_be_aborted>
SCSI opcode    : <CDB_of_cmd_to_be_aborted>
FCP rsp inf cod: 0x..                                   none (invalid)
FCP rsp IU     : ...                                    none (invalid)

Timestamp      : ...
Area           : SCSI
Subarea        : 00
Level          : 1
Exception      : -
CPU ID         : ..
Caller         : 0x...
Record ID      : 1
Tag            : lr_wait        LUN reset, before zfcp_erp_wait()
Request ID     : 0x0000000000000000                     none (invalid)
SCSI ID        : 0x<scsi_id>
SCSI LUN       : 0x<scsi_lun>
SCSI LUN high  : 0x<scsi_lun_high>
SCSI result    : 0x...                                  unrelated
SCSI retries   : 0x..                                   unrelated
SCSI allowed   : 0x..                                   unrelated
SCSI scribble  : 0x...                                  unrelated
SCSI opcode    : ...                                    unrelated
FCP rsp inf cod: 0x..                                   none (invalid)
FCP rsp IU     : ...                                    none (invalid)

Signed-off-by: Steffen Maier <maier@linux.ibm.com>
Fixes: 63caf367e1c9 ("[SCSI] zfcp: Improve reliability of SCSI eh handlers in zfcp")
Fixes: af4de36d911a ("[SCSI] zfcp: Block scsi_eh thread for rport state BLOCKED")
Cc: <stable@vger.kernel.org> #2.6.38+
Reviewed-by: Benjamin Block <bblock@linux.ibm.com>
---
 drivers/s390/scsi/zfcp_scsi.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/drivers/s390/scsi/zfcp_scsi.c b/drivers/s390/scsi/zfcp_scsi.c
index a62357f5e8b4..4fdb1665b0e6 100644
--- a/drivers/s390/scsi/zfcp_scsi.c
+++ b/drivers/s390/scsi/zfcp_scsi.c
@@ -181,6 +181,7 @@ static int zfcp_scsi_eh_abort_handler(struct scsi_cmnd *scpnt)
 		if (abrt_req)
 			break;
 
+		zfcp_dbf_scsi_abort("abrt_wt", scpnt, NULL);
 		zfcp_erp_wait(adapter);
 		ret = fc_block_scsi_eh(scpnt);
 		if (ret) {
@@ -277,6 +278,7 @@ static int zfcp_task_mgmt_function(struct scsi_cmnd *scpnt, u8 tm_flags)
 		if (fsf_req)
 			break;
 
+		zfcp_dbf_scsi_devreset("wait", scpnt, tm_flags, NULL);
 		zfcp_erp_wait(adapter);
 		ret = fc_block_scsi_eh(scpnt);
 		if (ret) {
-- 
2.16.3