Merge SCSI misc branch into isci-for-3.6 tag

13 files changed, 223 insertions, 43 deletions

diff --git a/drivers/s390/scsi/zfcp_aux.c b/drivers/s390/scsi/zfcp_aux.c
index aff8621de806..f6adde44f226 100644
--- a/drivers/s390/scsi/zfcp_aux.c
+++ b/drivers/s390/scsi/zfcp_aux.c
@@ -519,6 +519,7 @@ struct zfcp_port *zfcp_port_enqueue(struct zfcp_adapter *adapter, u64 wwpn,
 
 	rwlock_init(&port->unit_list_lock);
 	INIT_LIST_HEAD(&port->unit_list);
+	atomic_set(&port->units, 0);
 
 	INIT_WORK(&port->gid_pn_work, zfcp_fc_port_did_lookup);
 	INIT_WORK(&port->test_link_work, zfcp_fc_link_test_work);
diff --git a/drivers/s390/scsi/zfcp_ccw.c b/drivers/s390/scsi/zfcp_ccw.c
index e37f04551948..f2dd3a0a39eb 100644
--- a/drivers/s390/scsi/zfcp_ccw.c
+++ b/drivers/s390/scsi/zfcp_ccw.c
@@ -39,19 +39,25 @@ void zfcp_ccw_adapter_put(struct zfcp_adapter *adapter)
 	spin_unlock_irqrestore(&zfcp_ccw_adapter_ref_lock, flags);
 }
 
-static int zfcp_ccw_activate(struct ccw_device *cdev)
-
+/**
+ * zfcp_ccw_activate - activate adapter and wait for it to finish
+ * @cdev: pointer to belonging ccw device
+ * @clear: Status flags to clear.
+ * @tag: s390dbf trace record tag
+ */
+static int zfcp_ccw_activate(struct ccw_device *cdev, int clear, char *tag)
 {
 	struct zfcp_adapter *adapter = zfcp_ccw_adapter_by_cdev(cdev);
 
 	if (!adapter)
 		return 0;
 
+	zfcp_erp_clear_adapter_status(adapter, clear);
 	zfcp_erp_set_adapter_status(adapter, ZFCP_STATUS_COMMON_RUNNING);
 	zfcp_erp_adapter_reopen(adapter, ZFCP_STATUS_COMMON_ERP_FAILED,
-				"ccresu2");
+				tag);
 	zfcp_erp_wait(adapter);
-	flush_work(&adapter->scan_work);
+	flush_work(&adapter->scan_work); /* ok to call even if nothing queued */
 
 	zfcp_ccw_adapter_put(adapter);
 
@@ -164,26 +170,34 @@ static int zfcp_ccw_set_online(struct ccw_device *cdev)
 	BUG_ON(!zfcp_reqlist_isempty(adapter->req_list));
 	adapter->req_no = 0;
 
-	zfcp_ccw_activate(cdev);
+	zfcp_ccw_activate(cdev, 0, "ccsonl1");
+	/* scan for remote ports
+	   either at the end of any successful adapter recovery
+	   or only after the adapter recovery for setting a device online */
+	zfcp_fc_inverse_conditional_port_scan(adapter);
+	flush_work(&adapter->scan_work); /* ok to call even if nothing queued */
 	zfcp_ccw_adapter_put(adapter);
 	return 0;
 }
 
 /**
- * zfcp_ccw_set_offline - set_offline function of zfcp driver
+ * zfcp_ccw_offline_sync - shut down adapter and wait for it to finish
  * @cdev: pointer to belonging ccw device
+ * @set: Status flags to set.
+ * @tag: s390dbf trace record tag
  *
  * This function gets called by the common i/o layer and sets an adapter
  * into state offline.
  */
-static int zfcp_ccw_set_offline(struct ccw_device *cdev)
+static int zfcp_ccw_offline_sync(struct ccw_device *cdev, int set, char *tag)
 {
 	struct zfcp_adapter *adapter = zfcp_ccw_adapter_by_cdev(cdev);
 
 	if (!adapter)
 		return 0;
 
-	zfcp_erp_adapter_shutdown(adapter, 0, "ccsoff1");
+	zfcp_erp_set_adapter_status(adapter, set);
+	zfcp_erp_adapter_shutdown(adapter, 0, tag);
 	zfcp_erp_wait(adapter);
 
 	zfcp_ccw_adapter_put(adapter);
@@ -191,6 +205,18 @@ static int zfcp_ccw_set_offline(struct ccw_device *cdev)
 }
 
 /**
+ * zfcp_ccw_set_offline - set_offline function of zfcp driver
+ * @cdev: pointer to belonging ccw device
+ *
+ * This function gets called by the common i/o layer and sets an adapter
+ * into state offline.
+ */
+static int zfcp_ccw_set_offline(struct ccw_device *cdev)
+{
+	return zfcp_ccw_offline_sync(cdev, 0, "ccsoff1");
+}
+
+/**
  * zfcp_ccw_notify - ccw notify function
  * @cdev: pointer to belonging ccw device
  * @event: indicates if adapter was detached or attached
@@ -207,6 +233,11 @@ static int zfcp_ccw_notify(struct ccw_device *cdev, int event)
 
 	switch (event) {
 	case CIO_GONE:
+		if (atomic_read(&adapter->status) &
+		    ZFCP_STATUS_ADAPTER_SUSPENDED) { /* notification ignore */
+			zfcp_dbf_hba_basic("ccnigo1", adapter);
+			break;
+		}
 		dev_warn(&cdev->dev, "The FCP device has been detached\n");
 		zfcp_erp_adapter_shutdown(adapter, 0, "ccnoti1");
 		break;
@@ -216,6 +247,11 @@ static int zfcp_ccw_notify(struct ccw_device *cdev, int event)
 		zfcp_erp_adapter_shutdown(adapter, 0, "ccnoti2");
 		break;
 	case CIO_OPER:
+		if (atomic_read(&adapter->status) &
+		    ZFCP_STATUS_ADAPTER_SUSPENDED) { /* notification ignore */
+			zfcp_dbf_hba_basic("ccniop1", adapter);
+			break;
+		}
 		dev_info(&cdev->dev, "The FCP device is operational again\n");
 		zfcp_erp_set_adapter_status(adapter,
 					    ZFCP_STATUS_COMMON_RUNNING);
@@ -251,6 +287,28 @@ static void zfcp_ccw_shutdown(struct ccw_device *cdev)
 	zfcp_ccw_adapter_put(adapter);
 }
 
+static int zfcp_ccw_suspend(struct ccw_device *cdev)
+{
+	zfcp_ccw_offline_sync(cdev, ZFCP_STATUS_ADAPTER_SUSPENDED, "ccsusp1");
+	return 0;
+}
+
+static int zfcp_ccw_thaw(struct ccw_device *cdev)
+{
+	/* trace records for thaw and final shutdown during suspend
+	   can only be found in system dump until the end of suspend
+	   but not after resume because it's based on the memory image
+	   right after the very first suspend (freeze) callback */
+	zfcp_ccw_activate(cdev, 0, "ccthaw1");
+	return 0;
+}
+
+static int zfcp_ccw_resume(struct ccw_device *cdev)
+{
+	zfcp_ccw_activate(cdev, ZFCP_STATUS_ADAPTER_SUSPENDED, "ccresu1");
+	return 0;
+}
+
 struct ccw_driver zfcp_ccw_driver = {
 	.driver = {
 		.owner	= THIS_MODULE,
@@ -263,7 +321,7 @@ struct ccw_driver zfcp_ccw_driver = {
 	.set_offline = zfcp_ccw_set_offline,
 	.notify      = zfcp_ccw_notify,
 	.shutdown    = zfcp_ccw_shutdown,
-	.freeze      = zfcp_ccw_set_offline,
-	.thaw	     = zfcp_ccw_activate,
-	.restore     = zfcp_ccw_activate,
+	.freeze      = zfcp_ccw_suspend,
+	.thaw	     = zfcp_ccw_thaw,
+	.restore     = zfcp_ccw_resume,
 };
diff --git a/drivers/s390/scsi/zfcp_cfdc.c b/drivers/s390/scsi/zfcp_cfdc.c
index fbd8b4db6025..49b82e46629e 100644
--- a/drivers/s390/scsi/zfcp_cfdc.c
+++ b/drivers/s390/scsi/zfcp_cfdc.c
@@ -293,7 +293,7 @@ void zfcp_cfdc_adapter_access_changed(struct zfcp_adapter *adapter)
 	}
 	read_unlock_irqrestore(&adapter->port_list_lock, flags);
 
-	shost_for_each_device(sdev, port->adapter->scsi_host) {
+	shost_for_each_device(sdev, adapter->scsi_host) {
 		zfcp_sdev = sdev_to_zfcp(sdev);
 		status = atomic_read(&zfcp_sdev->status);
 		if ((status & ZFCP_STATUS_COMMON_ACCESS_DENIED) ||
diff --git a/drivers/s390/scsi/zfcp_dbf.c b/drivers/s390/scsi/zfcp_dbf.c
index 3c1d22097ad0..e1a8cc2526e7 100644
--- a/drivers/s390/scsi/zfcp_dbf.c
+++ b/drivers/s390/scsi/zfcp_dbf.c
@@ -191,7 +191,7 @@ void zfcp_dbf_hba_def_err(struct zfcp_adapter *adapter, u64 req_id, u16 scount,
 	length = min((u16)sizeof(struct qdio_buffer),
 		     (u16)ZFCP_DBF_PAY_MAX_REC);
 
-	while ((char *)pl[payload->counter] && payload->counter < scount) {
+	while (payload->counter < scount && (char *)pl[payload->counter]) {
 		memcpy(payload->data, (char *)pl[payload->counter], length);
 		debug_event(dbf->pay, 1, payload, zfcp_dbf_plen(length));
 		payload->counter++;
@@ -200,6 +200,26 @@ void zfcp_dbf_hba_def_err(struct zfcp_adapter *adapter, u64 req_id, u16 scount,
 	spin_unlock_irqrestore(&dbf->pay_lock, flags);
 }
 
+/**
+ * zfcp_dbf_hba_basic - trace event for basic adapter events
+ * @adapter: pointer to struct zfcp_adapter
+ */
+void zfcp_dbf_hba_basic(char *tag, struct zfcp_adapter *adapter)
+{
+	struct zfcp_dbf *dbf = adapter->dbf;
+	struct zfcp_dbf_hba *rec = &dbf->hba_buf;
+	unsigned long flags;
+
+	spin_lock_irqsave(&dbf->hba_lock, flags);
+	memset(rec, 0, sizeof(*rec));
+
+	memcpy(rec->tag, tag, ZFCP_DBF_TAG_LEN);
+	rec->id = ZFCP_DBF_HBA_BASIC;
+
+	debug_event(dbf->hba, 1, rec, sizeof(*rec));
+	spin_unlock_irqrestore(&dbf->hba_lock, flags);
+}
+
 static void zfcp_dbf_set_common(struct zfcp_dbf_rec *rec,
 				struct zfcp_adapter *adapter,
 				struct zfcp_port *port,
diff --git a/drivers/s390/scsi/zfcp_dbf.h b/drivers/s390/scsi/zfcp_dbf.h
index 714f087eb7a9..3ac7a4b30dd9 100644
--- a/drivers/s390/scsi/zfcp_dbf.h
+++ b/drivers/s390/scsi/zfcp_dbf.h
@@ -154,6 +154,7 @@ enum zfcp_dbf_hba_id {
 	ZFCP_DBF_HBA_RES	= 1,
 	ZFCP_DBF_HBA_USS	= 2,
 	ZFCP_DBF_HBA_BIT	= 3,
+	ZFCP_DBF_HBA_BASIC	= 4,
 };
 
 /**
diff --git a/drivers/s390/scsi/zfcp_def.h b/drivers/s390/scsi/zfcp_def.h
index 2955e1a3deaf..1305955cbf59 100644
--- a/drivers/s390/scsi/zfcp_def.h
+++ b/drivers/s390/scsi/zfcp_def.h
@@ -77,6 +77,7 @@ struct zfcp_reqlist;
 #define ZFCP_STATUS_ADAPTER_SIOSL_ISSUED	0x00000004
 #define ZFCP_STATUS_ADAPTER_XCONFIG_OK		0x00000008
 #define ZFCP_STATUS_ADAPTER_HOST_CON_INIT	0x00000010
+#define ZFCP_STATUS_ADAPTER_SUSPENDED		0x00000040
 #define ZFCP_STATUS_ADAPTER_ERP_PENDING		0x00000100
 #define ZFCP_STATUS_ADAPTER_LINK_UNPLUGGED	0x00000200
 #define ZFCP_STATUS_ADAPTER_DATA_DIV_ENABLED	0x00000400
@@ -204,6 +205,7 @@ struct zfcp_port {
 	struct zfcp_adapter    *adapter;       /* adapter used to access port */
 	struct list_head	unit_list;	/* head of logical unit list */
 	rwlock_t		unit_list_lock; /* unit list lock */
+	atomic_t		units;	       /* zfcp_unit count */
 	atomic_t	       status;	       /* status of this remote port */
 	u64		       wwnn;	       /* WWNN if known */
 	u64		       wwpn;	       /* WWPN */
diff --git a/drivers/s390/scsi/zfcp_erp.c b/drivers/s390/scsi/zfcp_erp.c
index 92d3df6ac8ba..4133ab6e20f1 100644
--- a/drivers/s390/scsi/zfcp_erp.c
+++ b/drivers/s390/scsi/zfcp_erp.c
@@ -1230,7 +1230,7 @@ static void zfcp_erp_action_cleanup(struct zfcp_erp_action *act, int result)
 	case ZFCP_ERP_ACTION_REOPEN_ADAPTER:
 		if (result == ZFCP_ERP_SUCCEEDED) {
 			register_service_level(&adapter->service_level);
-			queue_work(adapter->work_queue, &adapter->scan_work);
+			zfcp_fc_conditional_port_scan(adapter);
 			queue_work(adapter->work_queue, &adapter->ns_up_work);
 		} else
 			unregister_service_level(&adapter->service_level);
diff --git a/drivers/s390/scsi/zfcp_ext.h b/drivers/s390/scsi/zfcp_ext.h
index 36f422770ff5..1d3dd3f7d699 100644
--- a/drivers/s390/scsi/zfcp_ext.h
+++ b/drivers/s390/scsi/zfcp_ext.h
@@ -54,6 +54,7 @@ extern void zfcp_dbf_hba_fsf_res(char *, struct zfcp_fsf_req *);
 extern void zfcp_dbf_hba_bit_err(char *, struct zfcp_fsf_req *);
 extern void zfcp_dbf_hba_berr(struct zfcp_dbf *, struct zfcp_fsf_req *);
 extern void zfcp_dbf_hba_def_err(struct zfcp_adapter *, u64, u16, void **);
+extern void zfcp_dbf_hba_basic(char *, struct zfcp_adapter *);
 extern void zfcp_dbf_san_req(char *, struct zfcp_fsf_req *, u32);
 extern void zfcp_dbf_san_res(char *, struct zfcp_fsf_req *);
 extern void zfcp_dbf_san_in_els(char *, struct zfcp_fsf_req *);
@@ -98,6 +99,8 @@ extern void zfcp_fc_gs_destroy(struct zfcp_adapter *);
 extern int zfcp_fc_exec_bsg_job(struct fc_bsg_job *);
 extern int zfcp_fc_timeout_bsg_job(struct fc_bsg_job *);
 extern void zfcp_fc_sym_name_update(struct work_struct *);
+extern void zfcp_fc_conditional_port_scan(struct zfcp_adapter *);
+extern void zfcp_fc_inverse_conditional_port_scan(struct zfcp_adapter *);
 
 /* zfcp_fsf.c */
 extern struct kmem_cache *zfcp_fsf_qtcb_cache;
@@ -158,6 +161,7 @@ extern void zfcp_scsi_dif_sense_error(struct scsi_cmnd *, int);
 extern struct attribute_group zfcp_sysfs_unit_attrs;
 extern struct attribute_group zfcp_sysfs_adapter_attrs;
 extern struct attribute_group zfcp_sysfs_port_attrs;
+extern struct mutex zfcp_sysfs_port_units_mutex;
 extern struct device_attribute *zfcp_sysfs_sdev_attrs[];
 extern struct device_attribute *zfcp_sysfs_shost_attrs[];
 
diff --git a/drivers/s390/scsi/zfcp_fc.c b/drivers/s390/scsi/zfcp_fc.c
index 88688a80b2c1..ff598cd68b2d 100644
--- a/drivers/s390/scsi/zfcp_fc.c
+++ b/drivers/s390/scsi/zfcp_fc.c
@@ -26,6 +26,27 @@ static u32 zfcp_fc_rscn_range_mask[] = {
 	[ELS_ADDR_FMT_FAB]		= 0x000000,
 };
 
+static bool no_auto_port_rescan;
+module_param_named(no_auto_port_rescan, no_auto_port_rescan, bool, 0600);
+MODULE_PARM_DESC(no_auto_port_rescan,
+		 "no automatic port_rescan (default off)");
+
+void zfcp_fc_conditional_port_scan(struct zfcp_adapter *adapter)
+{
+	if (no_auto_port_rescan)
+		return;
+
+	queue_work(adapter->work_queue, &adapter->scan_work);
+}
+
+void zfcp_fc_inverse_conditional_port_scan(struct zfcp_adapter *adapter)
+{
+	if (!no_auto_port_rescan)
+		return;
+
+	queue_work(adapter->work_queue, &adapter->scan_work);
+}
+
 /**
  * zfcp_fc_post_event - post event to userspace via fc_transport
  * @work: work struct with enqueued events
@@ -206,7 +227,7 @@ static void zfcp_fc_incoming_rscn(struct zfcp_fsf_req *fsf_req)
 		zfcp_fc_enqueue_event(fsf_req->adapter, FCH_EVT_RSCN,
 				      *(u32 *)page);
 	}
-	queue_work(fsf_req->adapter->work_queue, &fsf_req->adapter->scan_work);
+	zfcp_fc_conditional_port_scan(fsf_req->adapter);
 }
 
 static void zfcp_fc_incoming_wwpn(struct zfcp_fsf_req *req, u64 wwpn)
diff --git a/drivers/s390/scsi/zfcp_fsf.c b/drivers/s390/scsi/zfcp_fsf.c
index e1c1efc2c5a0..c96320d79fbc 100644
--- a/drivers/s390/scsi/zfcp_fsf.c
+++ b/drivers/s390/scsi/zfcp_fsf.c
@@ -219,7 +219,7 @@ static void zfcp_fsf_status_read_handler(struct zfcp_fsf_req *req)
 		return;
 	}
 
-	zfcp_dbf_hba_fsf_uss("fssrh_2", req);
+	zfcp_dbf_hba_fsf_uss("fssrh_4", req);
 
 	switch (sr_buf->status_type) {
 	case FSF_STATUS_READ_PORT_CLOSED:
@@ -257,7 +257,7 @@ static void zfcp_fsf_status_read_handler(struct zfcp_fsf_req *req)
 		if (sr_buf->status_subtype & FSF_STATUS_READ_SUB_ACT_UPDATED)
 			zfcp_cfdc_adapter_access_changed(adapter);
 		if (sr_buf->status_subtype & FSF_STATUS_READ_SUB_INCOMING_ELS)
-			queue_work(adapter->work_queue, &adapter->scan_work);
+			zfcp_fc_conditional_port_scan(adapter);
 		break;
 	case FSF_STATUS_READ_CFDC_UPDATED:
 		zfcp_cfdc_adapter_access_changed(adapter);
@@ -437,6 +437,34 @@ void zfcp_fsf_req_dismiss_all(struct zfcp_adapter *adapter)
 	}
 }
 
+#define ZFCP_FSF_PORTSPEED_1GBIT	(1 <<  0)
+#define ZFCP_FSF_PORTSPEED_2GBIT	(1 <<  1)
+#define ZFCP_FSF_PORTSPEED_4GBIT	(1 <<  2)
+#define ZFCP_FSF_PORTSPEED_10GBIT	(1 <<  3)
+#define ZFCP_FSF_PORTSPEED_8GBIT	(1 <<  4)
+#define ZFCP_FSF_PORTSPEED_16GBIT	(1 <<  5)
+#define ZFCP_FSF_PORTSPEED_NOT_NEGOTIATED (1 << 15)
+
+static u32 zfcp_fsf_convert_portspeed(u32 fsf_speed)
+{
+	u32 fdmi_speed = 0;
+	if (fsf_speed & ZFCP_FSF_PORTSPEED_1GBIT)
+		fdmi_speed |= FC_PORTSPEED_1GBIT;
+	if (fsf_speed & ZFCP_FSF_PORTSPEED_2GBIT)
+		fdmi_speed |= FC_PORTSPEED_2GBIT;
+	if (fsf_speed & ZFCP_FSF_PORTSPEED_4GBIT)
+		fdmi_speed |= FC_PORTSPEED_4GBIT;
+	if (fsf_speed & ZFCP_FSF_PORTSPEED_10GBIT)
+		fdmi_speed |= FC_PORTSPEED_10GBIT;
+	if (fsf_speed & ZFCP_FSF_PORTSPEED_8GBIT)
+		fdmi_speed |= FC_PORTSPEED_8GBIT;
+	if (fsf_speed & ZFCP_FSF_PORTSPEED_16GBIT)
+		fdmi_speed |= FC_PORTSPEED_16GBIT;
+	if (fsf_speed & ZFCP_FSF_PORTSPEED_NOT_NEGOTIATED)
+		fdmi_speed |= FC_PORTSPEED_NOT_NEGOTIATED;
+	return fdmi_speed;
+}
+
 static int zfcp_fsf_exchange_config_evaluate(struct zfcp_fsf_req *req)
 {
 	struct fsf_qtcb_bottom_config *bottom = &req->qtcb->bottom.config;
@@ -456,7 +484,8 @@ static int zfcp_fsf_exchange_config_evaluate(struct zfcp_fsf_req *req)
 	fc_host_port_name(shost) = nsp->fl_wwpn;
 	fc_host_node_name(shost) = nsp->fl_wwnn;
 	fc_host_port_id(shost) = ntoh24(bottom->s_id);
-	fc_host_speed(shost) = bottom->fc_link_speed;
+	fc_host_speed(shost) =
+		zfcp_fsf_convert_portspeed(bottom->fc_link_speed);
 	fc_host_supported_classes(shost) = FC_COS_CLASS2 | FC_COS_CLASS3;
 
 	adapter->hydra_version = bottom->adapter_type;
@@ -580,7 +609,8 @@ static void zfcp_fsf_exchange_port_evaluate(struct zfcp_fsf_req *req)
 	} else
 		fc_host_permanent_port_name(shost) = fc_host_port_name(shost);
 	fc_host_maxframe_size(shost) = bottom->maximum_frame_size;
-	fc_host_supported_speeds(shost) = bottom->supported_speed;
+	fc_host_supported_speeds(shost) =
+		zfcp_fsf_convert_portspeed(bottom->supported_speed);
 	memcpy(fc_host_supported_fc4s(shost), bottom->supported_fc4_types,
 	       FC_FC4_LIST_SIZE);
 	memcpy(fc_host_active_fc4s(shost), bottom->active_fc4_types,
@@ -771,12 +801,14 @@ out:
 static void zfcp_fsf_abort_fcp_command_handler(struct zfcp_fsf_req *req)
 {
 	struct scsi_device *sdev = req->data;
-	struct zfcp_scsi_dev *zfcp_sdev = sdev_to_zfcp(sdev);
+	struct zfcp_scsi_dev *zfcp_sdev;
 	union fsf_status_qual *fsq = &req->qtcb->header.fsf_status_qual;
 
 	if (req->status & ZFCP_STATUS_FSFREQ_ERROR)
 		return;
 
+	zfcp_sdev = sdev_to_zfcp(sdev);
+
 	switch (req->qtcb->header.fsf_status) {
 	case FSF_PORT_HANDLE_NOT_VALID:
 		if (fsq->word[0] == fsq->word[1]) {
@@ -885,7 +917,7 @@ static void zfcp_fsf_send_ct_handler(struct zfcp_fsf_req *req)
 
 	switch (header->fsf_status) {
         case FSF_GOOD:
-		zfcp_dbf_san_res("fsscth1", req);
+		zfcp_dbf_san_res("fsscth2", req);
 		ct->status = 0;
 		break;
         case FSF_SERVICE_CLASS_NOT_SUPPORTED:
@@ -1739,13 +1771,15 @@ static void zfcp_fsf_open_lun_handler(struct zfcp_fsf_req *req)
 {
 	struct zfcp_adapter *adapter = req->adapter;
 	struct scsi_device *sdev = req->data;
-	struct zfcp_scsi_dev *zfcp_sdev = sdev_to_zfcp(sdev);
+	struct zfcp_scsi_dev *zfcp_sdev;
 	struct fsf_qtcb_header *header = &req->qtcb->header;
 	struct fsf_qtcb_bottom_support *bottom = &req->qtcb->bottom.support;
 
 	if (req->status & ZFCP_STATUS_FSFREQ_ERROR)
 		return;
 
+	zfcp_sdev = sdev_to_zfcp(sdev);
+
 	atomic_clear_mask(ZFCP_STATUS_COMMON_ACCESS_DENIED |
 			  ZFCP_STATUS_COMMON_ACCESS_BOXED |
 			  ZFCP_STATUS_LUN_SHARED |
@@ -1856,11 +1890,13 @@ out:
 static void zfcp_fsf_close_lun_handler(struct zfcp_fsf_req *req)
 {
 	struct scsi_device *sdev = req->data;
-	struct zfcp_scsi_dev *zfcp_sdev = sdev_to_zfcp(sdev);
+	struct zfcp_scsi_dev *zfcp_sdev;
 
 	if (req->status & ZFCP_STATUS_FSFREQ_ERROR)
 		return;
 
+	zfcp_sdev = sdev_to_zfcp(sdev);
+
 	switch (req->qtcb->header.fsf_status) {
 	case FSF_PORT_HANDLE_NOT_VALID:
 		zfcp_erp_adapter_reopen(zfcp_sdev->port->adapter, 0, "fscuh_1");
@@ -1950,7 +1986,7 @@ static void zfcp_fsf_req_trace(struct zfcp_fsf_req *req, struct scsi_cmnd *scsi)
 {
 	struct fsf_qual_latency_info *lat_in;
 	struct latency_cont *lat = NULL;
-	struct zfcp_scsi_dev *zfcp_sdev = sdev_to_zfcp(scsi->device);
+	struct zfcp_scsi_dev *zfcp_sdev;
 	struct zfcp_blk_drv_data blktrc;
 	int ticks = req->adapter->timer_ticks;
 
@@ -1965,6 +2001,7 @@ static void zfcp_fsf_req_trace(struct zfcp_fsf_req *req, struct scsi_cmnd *scsi)
 
 	if (req->adapter->adapter_features & FSF_FEATURE_MEASUREMENT_DATA &&
 	    !(req->status & ZFCP_STATUS_FSFREQ_ERROR)) {
+		zfcp_sdev = sdev_to_zfcp(scsi->device);
 		blktrc.flags |= ZFCP_BLK_LAT_VALID;
 		blktrc.channel_lat = lat_in->channel_lat * ticks;
 		blktrc.fabric_lat = lat_in->fabric_lat * ticks;
@@ -2002,12 +2039,14 @@ static void zfcp_fsf_fcp_handler_common(struct zfcp_fsf_req *req)
 {
 	struct scsi_cmnd *scmnd = req->data;
 	struct scsi_device *sdev = scmnd->device;
-	struct zfcp_scsi_dev *zfcp_sdev = sdev_to_zfcp(sdev);
+	struct zfcp_scsi_dev *zfcp_sdev;
 	struct fsf_qtcb_header *header = &req->qtcb->header;
 
 	if (unlikely(req->status & ZFCP_STATUS_FSFREQ_ERROR))
 		return;
 
+	zfcp_sdev = sdev_to_zfcp(sdev);
+
 	switch (header->fsf_status) {
 	case FSF_HANDLE_MISMATCH:
 	case FSF_PORT_HANDLE_NOT_VALID:
diff --git a/drivers/s390/scsi/zfcp_qdio.c b/drivers/s390/scsi/zfcp_qdio.c
index b9fffc8d94a7..50b5615848f6 100644
--- a/drivers/s390/scsi/zfcp_qdio.c
+++ b/drivers/s390/scsi/zfcp_qdio.c
@@ -102,18 +102,22 @@ static void zfcp_qdio_int_resp(struct ccw_device *cdev, unsigned int qdio_err,
 {
 	struct zfcp_qdio *qdio = (struct zfcp_qdio *) parm;
 	struct zfcp_adapter *adapter = qdio->adapter;
-	struct qdio_buffer_element *sbale;
 	int sbal_no, sbal_idx;
-	void *pl[ZFCP_QDIO_MAX_SBALS_PER_REQ + 1];
-	u64 req_id;
-	u8 scount;
 
 	if (unlikely(qdio_err)) {
-		memset(pl, 0, ZFCP_QDIO_MAX_SBALS_PER_REQ * sizeof(void *));
 		if (zfcp_adapter_multi_buffer_active(adapter)) {
+			void *pl[ZFCP_QDIO_MAX_SBALS_PER_REQ + 1];
+			struct qdio_buffer_element *sbale;
+			u64 req_id;
+			u8 scount;
+
+			memset(pl, 0,
+			       ZFCP_QDIO_MAX_SBALS_PER_REQ * sizeof(void *));
 			sbale = qdio->res_q[idx]->element;
 			req_id = (u64) sbale->addr;
-			scount = sbale->scount + 1; /* incl. signaling SBAL */
+			scount = min(sbale->scount + 1,
+				     ZFCP_QDIO_MAX_SBALS_PER_REQ + 1);
+				     /* incl. signaling SBAL */
 
 			for (sbal_no = 0; sbal_no < scount; sbal_no++) {
 				sbal_idx = (idx + sbal_no) %
diff --git a/drivers/s390/scsi/zfcp_sysfs.c b/drivers/s390/scsi/zfcp_sysfs.c
index c66af27b230b..1e0eb089dfba 100644
--- a/drivers/s390/scsi/zfcp_sysfs.c
+++ b/drivers/s390/scsi/zfcp_sysfs.c
@@ -227,6 +227,8 @@ static ssize_t zfcp_sysfs_port_rescan_store(struct device *dev,
 static ZFCP_DEV_ATTR(adapter, port_rescan, S_IWUSR, NULL,
 		     zfcp_sysfs_port_rescan_store);
 
+DEFINE_MUTEX(zfcp_sysfs_port_units_mutex);
+
 static ssize_t zfcp_sysfs_port_remove_store(struct device *dev,
 					    struct device_attribute *attr,
 					    const char *buf, size_t count)
@@ -249,6 +251,16 @@ static ssize_t zfcp_sysfs_port_remove_store(struct device *dev,
 	else
 		retval = 0;
 
+	mutex_lock(&zfcp_sysfs_port_units_mutex);
+	if (atomic_read(&port->units) > 0) {
+		retval = -EBUSY;
+		mutex_unlock(&zfcp_sysfs_port_units_mutex);
+		goto out;
+	}
+	/* port is about to be removed, so no more unit_add */
+	atomic_set(&port->units, -1);
+	mutex_unlock(&zfcp_sysfs_port_units_mutex);
+
 	write_lock_irq(&adapter->port_list_lock);
 	list_del(&port->list);
 	write_unlock_irq(&adapter->port_list_lock);
@@ -289,12 +301,14 @@ static ssize_t zfcp_sysfs_unit_add_store(struct device *dev,
 {
 	struct zfcp_port *port = container_of(dev, struct zfcp_port, dev);
 	u64 fcp_lun;
+	int retval;
 
 	if (strict_strtoull(buf, 0, (unsigned long long *) &fcp_lun))
 		return -EINVAL;
 
-	if (zfcp_unit_add(port, fcp_lun))
-		return -EINVAL;
+	retval = zfcp_unit_add(port, fcp_lun);
+	if (retval)
+		return retval;
 
 	return count;
 }
diff --git a/drivers/s390/scsi/zfcp_unit.c b/drivers/s390/scsi/zfcp_unit.c
index 3f2bff0d3aa2..1cd2b99ab256 100644
--- a/drivers/s390/scsi/zfcp_unit.c
+++ b/drivers/s390/scsi/zfcp_unit.c
@@ -104,7 +104,7 @@ static void zfcp_unit_release(struct device *dev)
 {
 	struct zfcp_unit *unit = container_of(dev, struct zfcp_unit, dev);
 
-	put_device(&unit->port->dev);
+	atomic_dec(&unit->port->units);
 	kfree(unit);
 }
 
@@ -119,16 +119,27 @@ static void zfcp_unit_release(struct device *dev)
 int zfcp_unit_add(struct zfcp_port *port, u64 fcp_lun)
 {
 	struct zfcp_unit *unit;
+	int retval = 0;
+
+	mutex_lock(&zfcp_sysfs_port_units_mutex);
+	if (atomic_read(&port->units) == -1) {
+		/* port is already gone */
+		retval = -ENODEV;
+		goto out;
+	}
 
 	unit = zfcp_unit_find(port, fcp_lun);
 	if (unit) {
 		put_device(&unit->dev);
-		return -EEXIST;
+		retval = -EEXIST;
+		goto out;
 	}
 
 	unit = kzalloc(sizeof(struct zfcp_unit), GFP_KERNEL);
-	if (!unit)
-		return -ENOMEM;
+	if (!unit) {
+		retval = -ENOMEM;
+		goto out;
+	}
 
 	unit->port = port;
 	unit->fcp_lun = fcp_lun;
@@ -139,28 +150,33 @@ int zfcp_unit_add(struct zfcp_port *port, u64 fcp_lun)
 	if (dev_set_name(&unit->dev, "0x%016llx",
 			 (unsigned long long) fcp_lun)) {
 		kfree(unit);
-		return -ENOMEM;
+		retval = -ENOMEM;
+		goto out;
 	}
 
-	get_device(&port->dev);
-
 	if (device_register(&unit->dev)) {
 		put_device(&unit->dev);
-		return -ENOMEM;
+		retval = -ENOMEM;
+		goto out;
 	}
 
 	if (sysfs_create_group(&unit->dev.kobj, &zfcp_sysfs_unit_attrs)) {
 		device_unregister(&unit->dev);
-		return -EINVAL;
+		retval = -EINVAL;
+		goto out;
 	}
 
+	atomic_inc(&port->units); /* under zfcp_sysfs_port_units_mutex ! */
+
 	write_lock_irq(&port->unit_list_lock);
 	list_add_tail(&unit->list, &port->unit_list);
 	write_unlock_irq(&port->unit_list_lock);
 
 	zfcp_unit_scsi_scan(unit);
 
-	return 0;
+out:
+	mutex_unlock(&zfcp_sysfs_port_units_mutex);
+	return retval;
 }
 
 /**