get_device() and its internally used kobject_get() only return NULL
if they get passed NULL as argument. zfcp_get_port_by_wwpn() loops over
adapter->port_list so the iteration variable port is always non-NULL.
Struct device is embedded in struct zfcp_port so &port->dev is always
non-NULL. This is the argument to get_device().
However, if we get an fc_rport in terminate_rport_io() for which we cannot
find a match within zfcp_get_port_by_wwpn(), the latter can return NULL.
v2.6.30 commit 70932935b61e ("[SCSI] zfcp: Fix oops when port disappears")
introduced an early return without adding a trace record for this case.
Even if we don't need recovery in this case, for debugging we should still
see that our callback was invoked originally by scsi_transport_fc.
Example trace record formatted with zfcpdbf from s390-tools:
Timestamp : ...
Area : REC
Subarea : 00
Level : 1
Exception : -
CPU ID : ..
Caller : 0x...
Record ID : 1
Tag : sctrpin SCSI terminate rport I/O, no zfcp port
LUN : 0xffffffffffffffff none (invalid)
WWPN : 0x<wwpn> WWPN
D_ID : 0x<n_port_id> N_Port-ID
Adapter status : 0x...
Port status : 0xffffffff unknown (-1)
LUN status : 0x00000000 none (invalid)
Ready count : 0x...
Running count : 0x...
ERP want : 0x03 ZFCP_ERP_ACTION_REOPEN_PORT_FORCED
ERP need : 0xc0 ZFCP_ERP_ACTION_NONE
Signed-off-by: Steffen Maier <ma...@linux.ibm.com>
Fixes: 70932935b61e ("[SCSI] zfcp: Fix oops when port disappears")
Cc: <sta...@vger.kernel.org> #2.6.38+
Reviewed-by: Benjamin Block <bbl...@linux.ibm.com>
---
drivers/s390/scsi/zfcp_erp.c | 20 ++++++++++++++++++++
drivers/s390/scsi/zfcp_ext.h | 3 +++
drivers/s390/scsi/zfcp_scsi.c | 5 +++++
3 files changed, 28 insertions(+)
diff --git a/drivers/s390/scsi/zfcp_erp.c b/drivers/s390/scsi/zfcp_erp.c
index d9cd25b56cfa..3489b1bc9121 100644
--- a/drivers/s390/scsi/zfcp_erp.c
+++ b/drivers/s390/scsi/zfcp_erp.c
@@ -283,6 +283,26 @@ static int zfcp_erp_action_enqueue(int want, struct
zfcp_adapter *adapter,
return retval;
}
+void zfcp_erp_port_forced_no_port_dbf(char *id, struct zfcp_adapter *adapter,
+ u64 port_name, u32 port_id)
+{
+ unsigned long flags;
+ static /* don't waste stack */ struct zfcp_port tmpport;
+
+ write_lock_irqsave(&adapter->erp_lock, flags);
+ /* Stand-in zfcp port with fields just good enough for
+ * zfcp_dbf_rec_trig() and zfcp_dbf_set_common().
+ * Under lock because tmpport is static.
+ */
+ atomic_set(&tmpport.status, -1); /* unknown */
+ tmpport.wwpn = port_name;
+ tmpport.d_id = port_id;
+ zfcp_dbf_rec_trig(id, adapter, &tmpport, NULL,
+ ZFCP_ERP_ACTION_REOPEN_PORT_FORCED,
+ ZFCP_ERP_ACTION_NONE);
+ write_unlock_irqrestore(&adapter->erp_lock, flags);
+}
+
static int _zfcp_erp_adapter_reopen(struct zfcp_adapter *adapter,
int clear_mask, char *id)
{
diff --git a/drivers/s390/scsi/zfcp_ext.h b/drivers/s390/scsi/zfcp_ext.h
index e55f42ce1168..3299bd345076 100644
--- a/drivers/s390/scsi/zfcp_ext.h
+++ b/drivers/s390/scsi/zfcp_ext.h
@@ -55,6 +55,9 @@ extern void zfcp_dbf_scsi_eh(char *tag, struct zfcp_adapter
*adapter,
/* zfcp_erp.c */
extern void zfcp_erp_set_adapter_status(struct zfcp_adapter *, u32);
extern void zfcp_erp_clear_adapter_status(struct zfcp_adapter *, u32);
+extern void zfcp_erp_port_forced_no_port_dbf(char *id,
+ struct zfcp_adapter *adapter,
+ u64 port_name, u32 port_id);
extern void zfcp_erp_adapter_reopen(struct zfcp_adapter *, int, char *);
extern void zfcp_erp_adapter_shutdown(struct zfcp_adapter *, int, char *);
extern void zfcp_erp_set_port_status(struct zfcp_port *, u32);
diff --git a/drivers/s390/scsi/zfcp_scsi.c b/drivers/s390/scsi/zfcp_scsi.c
index 4fdb1665b0e6..478e7ef9ea2f 100644
--- a/drivers/s390/scsi/zfcp_scsi.c
+++ b/drivers/s390/scsi/zfcp_scsi.c
@@ -605,6 +605,11 @@ static void zfcp_scsi_terminate_rport_io(struct fc_rport
*rport)
if (port) {
zfcp_erp_port_forced_reopen(port, 0, "sctrpi1");
put_device(&port->dev);
+ } else {
+ zfcp_erp_port_forced_no_port_dbf(
+ "sctrpin", adapter,
+ rport->port_name /* zfcp_scsi_rport_register */,
+ rport->port_id /* zfcp_scsi_rport_register */);
}
}
--
2.16.3
