For problem determination we need to see whether and why we were successful or not. This allows deduction of scsi_eh escalation.
Example trace record formatted with zfcpdbf from s390-tools:
Timestamp : ... Area : SCSI Subarea : 00 Level : 1 Exception : - CPU ID : .. Caller : 0x... Record ID : 1 Tag : schrh_r SCSI host reset handler result Request ID : 0x0000000000000000 none (invalid) SCSI ID : 0xffffffff none (invalid) SCSI LUN : 0xffffffff none (invalid) SCSI LUN high : 0xffffffff none (invalid) SCSI result : 0x00002002 field re-used for midlayer value: SUCCESS or in other cases: 0x2009 == FAST_IO_FAIL SCSI retries : 0xff none (invalid) SCSI allowed : 0xff none (invalid) SCSI scribble : 0xffffffffffffffff none (invalid) SCSI opcode : ffffffff ffffffff ffffffff ffffffff none (invalid) FCP rsp inf cod: 0xff none (invalid) FCP rsp IU : 00000000 00000000 00000000 00000000 none (invalid) 00000000 00000000
v2.6.35 commit a1dbfddd02d2 ("[SCSI] zfcp: Pass return code from fc_block_scsi_eh to scsi eh") introduced the first return with something other than the previously hardcoded single SUCCESS return path.
Signed-off-by: Steffen Maier maier@linux.ibm.com Fixes: a1dbfddd02d2 ("[SCSI] zfcp: Pass return code from fc_block_scsi_eh to scsi eh") Cc: stable@vger.kernel.org #2.6.38+ Reviewed-by: Jens Remus jremus@linux.ibm.com Reviewed-by: Benjamin Block bblock@linux.ibm.com --- drivers/s390/scsi/zfcp_dbf.c | 40 ++++++++++++++++++++++++++++++++++++++++ drivers/s390/scsi/zfcp_ext.h | 2 ++ drivers/s390/scsi/zfcp_scsi.c | 11 ++++++----- 3 files changed, 48 insertions(+), 5 deletions(-)
diff --git a/drivers/s390/scsi/zfcp_dbf.c b/drivers/s390/scsi/zfcp_dbf.c index a8b831000b2d..1e5ea5e4992b 100644 --- a/drivers/s390/scsi/zfcp_dbf.c +++ b/drivers/s390/scsi/zfcp_dbf.c @@ -643,6 +643,46 @@ void zfcp_dbf_scsi(char *tag, int level, struct scsi_cmnd *sc, spin_unlock_irqrestore(&dbf->scsi_lock, flags); }
+/** + * zfcp_dbf_scsi_eh() - Trace event for special cases of scsi_eh callbacks. + * @tag: Identifier for event. + * @adapter: Pointer to zfcp adapter as context for this event. + * @scsi_id: SCSI ID/target to indicate scope of task management function (TMF). + * @ret: Return value of calling function. + * + * This SCSI trace variant does not depend on any of: + * scsi_cmnd, zfcp_fsf_req, scsi_device. + */ +void zfcp_dbf_scsi_eh(char *tag, struct zfcp_adapter *adapter, + unsigned int scsi_id, int ret) +{ + struct zfcp_dbf *dbf = adapter->dbf; + struct zfcp_dbf_scsi *rec = &dbf->scsi_buf; + unsigned long flags; + static int const level = 1; + + if (unlikely(!debug_level_enabled(adapter->dbf->scsi, level))) + return; + + spin_lock_irqsave(&dbf->scsi_lock, flags); + memset(rec, 0, sizeof(*rec)); + + memcpy(rec->tag, tag, ZFCP_DBF_TAG_LEN); + rec->id = ZFCP_DBF_SCSI_CMND; + rec->scsi_result = ret; /* re-use field, int is 4 bytes and fits */ + rec->scsi_retries = ~0; + rec->scsi_allowed = ~0; + rec->fcp_rsp_info = ~0; + rec->scsi_id = scsi_id; + rec->scsi_lun = (u32)ZFCP_DBF_INVALID_LUN; + rec->scsi_lun_64_hi = (u32)(ZFCP_DBF_INVALID_LUN >> 32); + rec->host_scribble = ~0; + memset(rec->scsi_opcode, 0xff, ZFCP_DBF_SCSI_OPCODE); + + debug_event(dbf->scsi, level, rec, sizeof(*rec)); + spin_unlock_irqrestore(&dbf->scsi_lock, flags); +} + static debug_info_t *zfcp_dbf_reg(const char *name, int size, int rec_size) { struct debug_info *d; diff --git a/drivers/s390/scsi/zfcp_ext.h b/drivers/s390/scsi/zfcp_ext.h index bf8ea4df2bb8..e55f42ce1168 100644 --- a/drivers/s390/scsi/zfcp_ext.h +++ b/drivers/s390/scsi/zfcp_ext.h @@ -49,6 +49,8 @@ extern void zfcp_dbf_san_res(char *, struct zfcp_fsf_req *); extern void zfcp_dbf_san_in_els(char *, struct zfcp_fsf_req *); extern void zfcp_dbf_scsi(char *, int, struct scsi_cmnd *, struct zfcp_fsf_req *); +extern void zfcp_dbf_scsi_eh(char *tag, struct zfcp_adapter *adapter, + unsigned int scsi_id, int ret);
/* zfcp_erp.c */ extern void zfcp_erp_set_adapter_status(struct zfcp_adapter *, u32); diff --git a/drivers/s390/scsi/zfcp_scsi.c b/drivers/s390/scsi/zfcp_scsi.c index 4d2ba5682493..a62357f5e8b4 100644 --- a/drivers/s390/scsi/zfcp_scsi.c +++ b/drivers/s390/scsi/zfcp_scsi.c @@ -323,15 +323,16 @@ static int zfcp_scsi_eh_host_reset_handler(struct scsi_cmnd *scpnt) { struct zfcp_scsi_dev *zfcp_sdev = sdev_to_zfcp(scpnt->device); struct zfcp_adapter *adapter = zfcp_sdev->port->adapter; - int ret; + int ret = SUCCESS, fc_ret;
zfcp_erp_adapter_reopen(adapter, 0, "schrh_1"); zfcp_erp_wait(adapter); - ret = fc_block_scsi_eh(scpnt); - if (ret) - return ret; + fc_ret = fc_block_scsi_eh(scpnt); + if (fc_ret) + ret = fc_ret;
- return SUCCESS; + zfcp_dbf_scsi_eh("schrh_r", adapter, ~0, ret); + return ret; }
struct scsi_transport_template *zfcp_scsi_transport_template;