[PATCH 3.16 060/366] scsi: zfcp: fix missing SCSI trace for result of eh_host_reset_handler

Ben Hutchings
2018-11-11T20:12:55Z

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

commit df30781699f53e4fd4c494c6f7dd16e3d5c21d30 upstream.

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")
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>
[bwh: Backported to 3.16: Drop assignment to zfcp_dbf_scsi::scsi_lun_64_hi
which doesn't exist here]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
---
--- a/drivers/s390/scsi/zfcp_dbf.c
+++ b/drivers/s390/scsi/zfcp_dbf.c
@@ -624,6 +624,45 @@ void zfcp_dbf_scsi(char *tag, int level,
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->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;
--- a/drivers/s390/scsi/zfcp_ext.h
+++ b/drivers/s390/scsi/zfcp_ext.h
@@ -52,6 +52,8 @@ extern void zfcp_dbf_san_res(char *, str
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);
--- a/drivers/s390/scsi/zfcp_scsi.c
+++ b/drivers/s390/scsi/zfcp_scsi.c
@@ -343,15 +343,16 @@ static int zfcp_scsi_eh_host_reset_handl
{
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;