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) {