[SCSI] zfcp: support for hardware data router

FICON Express8S supports hardware data router, which requires an
adapted qdio request format.
This part 2/2 exploits the functionality in zfcp.

Signed-off-by: Swen Schillig <swen@vnet.ibm.com>
Signed-off-by: Steffen Maier <maier@linux.vnet.ibm.com>
Signed-off-by: James Bottomley <JBottomley@Parallels.com>

7 files changed, 195 insertions, 60 deletions

diff --git a/drivers/s390/scsi/zfcp_dbf.c b/drivers/s390/scsi/zfcp_dbf.c
index 96d1462e0bf..967e7b70e97 100644
--- a/drivers/s390/scsi/zfcp_dbf.c
+++ b/drivers/s390/scsi/zfcp_dbf.c
@@ -163,6 +163,42 @@ void zfcp_dbf_hba_bit_err(char *tag, struct zfcp_fsf_req *req)
 	spin_unlock_irqrestore(&dbf->hba_lock, flags);
 }
 
+/**
+ * zfcp_dbf_hba_def_err - trace event for deferred error messages
+ * @adapter: pointer to struct zfcp_adapter
+ * @req_id: request id which caused the deferred error message
+ * @scount: number of sbals incl. the signaling sbal
+ * @pl: array of all involved sbals
+ */
+void zfcp_dbf_hba_def_err(struct zfcp_adapter *adapter, u64 req_id, u16 scount,
+			  void **pl)
+{
+	struct zfcp_dbf *dbf = adapter->dbf;
+	struct zfcp_dbf_pay *payload = &dbf->pay_buf;
+	unsigned long flags;
+	u16 length;
+
+	if (!pl)
+		return;
+
+	spin_lock_irqsave(&dbf->pay_lock, flags);
+	memset(payload, 0, sizeof(*payload));
+
+	memcpy(payload->area, "def_err", 7);
+	payload->fsf_req_id = req_id;
+	payload->counter = 0;
+	length = min((u16)sizeof(struct qdio_buffer),
+		     (u16)ZFCP_DBF_PAY_MAX_REC);
+
+	while ((char *)pl[payload->counter] && payload->counter < scount) {
+		memcpy(payload->data, (char *)pl[payload->counter], length);
+		debug_event(dbf->pay, 1, payload, zfcp_dbf_plen(length));
+		payload->counter++;
+	}
+
+	spin_unlock_irqrestore(&dbf->pay_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_def.h b/drivers/s390/scsi/zfcp_def.h
index 527ba48eea5..ed5d921e82c 100644
--- a/drivers/s390/scsi/zfcp_def.h
+++ b/drivers/s390/scsi/zfcp_def.h
@@ -72,6 +72,7 @@ struct zfcp_reqlist;
 #define ZFCP_STATUS_COMMON_NOESC		0x00200000
 
 /* adapter status */
+#define ZFCP_STATUS_ADAPTER_MB_ACT		0x00000001
 #define ZFCP_STATUS_ADAPTER_QDIOUP		0x00000002
 #define ZFCP_STATUS_ADAPTER_SIOSL_ISSUED	0x00000004
 #define ZFCP_STATUS_ADAPTER_XCONFIG_OK		0x00000008
@@ -314,4 +315,10 @@ struct zfcp_fsf_req {
 	void			(*handler)(struct zfcp_fsf_req *);
 };
 
+static inline
+int zfcp_adapter_multi_buffer_active(struct zfcp_adapter *adapter)
+{
+	return atomic_read(&adapter->status) & ZFCP_STATUS_ADAPTER_MB_ACT;
+}
+
 #endif /* ZFCP_DEF_H */
diff --git a/drivers/s390/scsi/zfcp_ext.h b/drivers/s390/scsi/zfcp_ext.h
index 03627cfd81c..2302e1cfb76 100644
--- a/drivers/s390/scsi/zfcp_ext.h
+++ b/drivers/s390/scsi/zfcp_ext.h
@@ -53,6 +53,7 @@ extern void zfcp_dbf_hba_fsf_uss(char *, struct zfcp_fsf_req *);
 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_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 *);
diff --git a/drivers/s390/scsi/zfcp_fsf.c b/drivers/s390/scsi/zfcp_fsf.c
index fa86c6a2857..e9a787e2e6a 100644
--- a/drivers/s390/scsi/zfcp_fsf.c
+++ b/drivers/s390/scsi/zfcp_fsf.c
@@ -936,39 +936,47 @@ static int zfcp_fsf_setup_ct_els_sbals(struct zfcp_fsf_req *req,
 				       struct scatterlist *sg_resp)
 {
 	struct zfcp_adapter *adapter = req->adapter;
+	struct zfcp_qdio *qdio = adapter->qdio;
+	struct fsf_qtcb *qtcb = req->qtcb;
 	u32 feat = adapter->adapter_features;
-	int bytes;
 
-	if (!(feat & FSF_FEATURE_ELS_CT_CHAINED_SBALS)) {
-		if (!zfcp_qdio_sg_one_sbale(sg_req) ||
-		    !zfcp_qdio_sg_one_sbale(sg_resp))
-			return -EOPNOTSUPP;
+	if (zfcp_adapter_multi_buffer_active(adapter)) {
+		if (zfcp_qdio_sbals_from_sg(qdio, &req->qdio_req, sg_req))
+			return -EIO;
+		if (zfcp_qdio_sbals_from_sg(qdio, &req->qdio_req, sg_resp))
+			return -EIO;
 
-		zfcp_fsf_setup_ct_els_unchained(adapter->qdio, &req->qdio_req,
-						sg_req, sg_resp);
+		zfcp_qdio_set_data_div(qdio, &req->qdio_req,
+					zfcp_qdio_sbale_count(sg_req));
+		zfcp_qdio_set_sbale_last(qdio, &req->qdio_req);
+		zfcp_qdio_set_scount(qdio, &req->qdio_req);
 		return 0;
 	}
 
 	/* use single, unchained SBAL if it can hold the request */
 	if (zfcp_qdio_sg_one_sbale(sg_req) && zfcp_qdio_sg_one_sbale(sg_resp)) {
-		zfcp_fsf_setup_ct_els_unchained(adapter->qdio, &req->qdio_req,
+		zfcp_fsf_setup_ct_els_unchained(qdio, &req->qdio_req,
 						sg_req, sg_resp);
 		return 0;
 	}
 
-	bytes = zfcp_qdio_sbals_from_sg(adapter->qdio, &req->qdio_req, sg_req);
-	if (bytes <= 0)
+	if (!(feat & FSF_FEATURE_ELS_CT_CHAINED_SBALS))
+		return -EOPNOTSUPP;
+
+	if (zfcp_qdio_sbals_from_sg(qdio, &req->qdio_req, sg_req))
 		return -EIO;
-	zfcp_qdio_set_sbale_last(adapter->qdio, &req->qdio_req);
-	req->qtcb->bottom.support.req_buf_length = bytes;
-	zfcp_qdio_skip_to_last_sbale(&req->qdio_req);
 
-	bytes = zfcp_qdio_sbals_from_sg(adapter->qdio, &req->qdio_req,
-					sg_resp);
-	req->qtcb->bottom.support.resp_buf_length = bytes;
-	if (bytes <= 0)
+	qtcb->bottom.support.req_buf_length = zfcp_qdio_real_bytes(sg_req);
+
+	zfcp_qdio_set_sbale_last(qdio, &req->qdio_req);
+	zfcp_qdio_skip_to_last_sbale(qdio, &req->qdio_req);
+
+	if (zfcp_qdio_sbals_from_sg(qdio, &req->qdio_req, sg_resp))
 		return -EIO;
-	zfcp_qdio_set_sbale_last(adapter->qdio, &req->qdio_req);
+
+	qtcb->bottom.support.resp_buf_length = zfcp_qdio_real_bytes(sg_resp);
+
+	zfcp_qdio_set_sbale_last(qdio, &req->qdio_req);
 
 	return 0;
 }
@@ -1119,7 +1127,8 @@ int zfcp_fsf_send_els(struct zfcp_adapter *adapter, u32 d_id,
 
 	req->status |= ZFCP_STATUS_FSFREQ_CLEANUP;
 
-	zfcp_qdio_sbal_limit(qdio, &req->qdio_req, 2);
+	if (!zfcp_adapter_multi_buffer_active(adapter))
+		zfcp_qdio_sbal_limit(qdio, &req->qdio_req, 2);
 
 	ret = zfcp_fsf_setup_ct_els(req, els->req, els->resp, timeout);
 
@@ -2162,7 +2171,7 @@ int zfcp_fsf_fcp_cmnd(struct scsi_cmnd *scsi_cmnd)
 	struct zfcp_fsf_req *req;
 	struct fcp_cmnd *fcp_cmnd;
 	u8 sbtype = SBAL_SFLAGS0_TYPE_READ;
-	int real_bytes, retval = -EIO, dix_bytes = 0;
+	int retval = -EIO;
 	struct scsi_device *sdev = scsi_cmnd->device;
 	struct zfcp_scsi_dev *zfcp_sdev = sdev_to_zfcp(sdev);
 	struct zfcp_adapter *adapter = zfcp_sdev->port->adapter;
@@ -2216,18 +2225,22 @@ int zfcp_fsf_fcp_cmnd(struct scsi_cmnd *scsi_cmnd)
 	if (scsi_prot_sg_count(scsi_cmnd)) {
 		zfcp_qdio_set_data_div(qdio, &req->qdio_req,
 				       scsi_prot_sg_count(scsi_cmnd));
-		dix_bytes = zfcp_qdio_sbals_from_sg(qdio, &req->qdio_req,
+		retval = zfcp_qdio_sbals_from_sg(qdio, &req->qdio_req,
+						 scsi_prot_sglist(scsi_cmnd));
+		if (retval)
+			goto failed_scsi_cmnd;
+		io->prot_data_length = zfcp_qdio_real_bytes(
 						scsi_prot_sglist(scsi_cmnd));
-		io->prot_data_length = dix_bytes;
 	}
 
-	real_bytes = zfcp_qdio_sbals_from_sg(qdio, &req->qdio_req,
-					     scsi_sglist(scsi_cmnd));
-
-	if (unlikely(real_bytes < 0) || unlikely(dix_bytes < 0))
+	retval = zfcp_qdio_sbals_from_sg(qdio, &req->qdio_req,
+					 scsi_sglist(scsi_cmnd));
+	if (unlikely(retval))
 		goto failed_scsi_cmnd;
 
 	zfcp_qdio_set_sbale_last(adapter->qdio, &req->qdio_req);
+	if (zfcp_adapter_multi_buffer_active(adapter))
+		zfcp_qdio_set_scount(qdio, &req->qdio_req);
 
 	retval = zfcp_fsf_req_send(req);
 	if (unlikely(retval))
@@ -2329,7 +2342,7 @@ struct zfcp_fsf_req *zfcp_fsf_control_file(struct zfcp_adapter *adapter,
 	struct zfcp_qdio *qdio = adapter->qdio;
 	struct zfcp_fsf_req *req = NULL;
 	struct fsf_qtcb_bottom_support *bottom;
-	int retval = -EIO, bytes;
+	int retval = -EIO;
 	u8 direction;
 
 	if (!(adapter->adapter_features & FSF_FEATURE_CFDC))
@@ -2362,13 +2375,17 @@ struct zfcp_fsf_req *zfcp_fsf_control_file(struct zfcp_adapter *adapter,
 	bottom->operation_subtype = FSF_CFDC_OPERATION_SUBTYPE;
 	bottom->option = fsf_cfdc->option;
 
-	bytes = zfcp_qdio_sbals_from_sg(qdio, &req->qdio_req, fsf_cfdc->sg);
+	retval = zfcp_qdio_sbals_from_sg(qdio, &req->qdio_req, fsf_cfdc->sg);
 
-	if (bytes != ZFCP_CFDC_MAX_SIZE) {
+	if (retval ||
+		(zfcp_qdio_real_bytes(fsf_cfdc->sg) != ZFCP_CFDC_MAX_SIZE)) {
 		zfcp_fsf_req_free(req);
+		retval = -EIO;
 		goto out;
 	}
-	zfcp_qdio_set_sbale_last(adapter->qdio, &req->qdio_req);
+	zfcp_qdio_set_sbale_last(qdio, &req->qdio_req);
+	if (zfcp_adapter_multi_buffer_active(adapter))
+		zfcp_qdio_set_scount(qdio, &req->qdio_req);
 
 	zfcp_fsf_start_timer(req, ZFCP_FSF_REQUEST_TIMEOUT);
 	retval = zfcp_fsf_req_send(req);
diff --git a/drivers/s390/scsi/zfcp_qdio.c b/drivers/s390/scsi/zfcp_qdio.c
index d9c40ea73ee..df9e69f5474 100644
--- a/drivers/s390/scsi/zfcp_qdio.c
+++ b/drivers/s390/scsi/zfcp_qdio.c
@@ -15,6 +15,10 @@
 
 #define QBUFF_PER_PAGE		(PAGE_SIZE / sizeof(struct qdio_buffer))
 
+static bool enable_multibuffer;
+module_param_named(datarouter, enable_multibuffer, bool, 0400);
+MODULE_PARM_DESC(datarouter, "Enable hardware data router support");
+
 static int zfcp_qdio_buffers_enqueue(struct qdio_buffer **sbal)
 {
 	int pos;
@@ -37,8 +41,11 @@ static void zfcp_qdio_handler_error(struct zfcp_qdio *qdio, char *id,
 
 	dev_warn(&adapter->ccw_device->dev, "A QDIO problem occurred\n");
 
-	if (qdio_err & QDIO_ERROR_SLSB_STATE)
+	if (qdio_err & QDIO_ERROR_SLSB_STATE) {
 		zfcp_qdio_siosl(adapter);
+		zfcp_erp_adapter_shutdown(adapter, 0, id);
+		return;
+	}
 	zfcp_erp_adapter_reopen(adapter,
 				ZFCP_STATUS_ADAPTER_LINK_UNPLUGGED |
 				ZFCP_STATUS_COMMON_ERP_FAILED, id);
@@ -93,9 +100,27 @@ static void zfcp_qdio_int_resp(struct ccw_device *cdev, unsigned int qdio_err,
 			       unsigned long parm)
 {
 	struct zfcp_qdio *qdio = (struct zfcp_qdio *) parm;
-	int sbal_idx, sbal_no;
+	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)) {
+			sbale = qdio->res_q[idx]->element;
+			req_id = (u64) sbale->addr;
+			scount = sbale->scount + 1; /* incl. signaling SBAL */
+
+			for (sbal_no = 0; sbal_no < scount; sbal_no++) {
+				sbal_idx = (idx + sbal_no) %
+					QDIO_MAX_BUFFERS_PER_Q;
+				pl[sbal_no] = qdio->res_q[sbal_idx];
+			}
+			zfcp_dbf_hba_def_err(adapter, req_id, scount, pl);
+		}
 		zfcp_qdio_handler_error(qdio, "qdires1", qdio_err);
 		return;
 	}
@@ -155,7 +180,7 @@ zfcp_qdio_sbal_chain(struct zfcp_qdio *qdio, struct zfcp_qdio_req *q_req)
 static struct qdio_buffer_element *
 zfcp_qdio_sbale_next(struct zfcp_qdio *qdio, struct zfcp_qdio_req *q_req)
 {
-	if (q_req->sbale_curr == ZFCP_QDIO_LAST_SBALE_PER_SBAL)
+	if (q_req->sbale_curr == qdio->max_sbale_per_sbal - 1)
 		return zfcp_qdio_sbal_chain(qdio, q_req);
 	q_req->sbale_curr++;
 	return zfcp_qdio_sbale_curr(qdio, q_req);
@@ -167,13 +192,12 @@ zfcp_qdio_sbale_next(struct zfcp_qdio *qdio, struct zfcp_qdio_req *q_req)
  * @q_req: pointer to struct zfcp_qdio_req
  * @sg: scatter-gather list
  * @max_sbals: upper bound for number of SBALs to be used
- * Returns: number of bytes, or error (negativ)
+ * Returns: zero or -EINVAL on error
  */
 int zfcp_qdio_sbals_from_sg(struct zfcp_qdio *qdio, struct zfcp_qdio_req *q_req,
 			    struct scatterlist *sg)
 {
 	struct qdio_buffer_element *sbale;
-	int bytes = 0;
 
 	/* set storage-block type for this request */
 	sbale = zfcp_qdio_sbale_req(qdio, q_req);
@@ -187,14 +211,10 @@ int zfcp_qdio_sbals_from_sg(struct zfcp_qdio *qdio, struct zfcp_qdio_req *q_req,
 					     q_req->sbal_number);
 			return -EINVAL;
 		}
-
 		sbale->addr = sg_virt(sg);
 		sbale->length = sg->length;
-
-		bytes += sg->length;
 	}
-
-	return bytes;
+	return 0;
 }
 
 static int zfcp_qdio_sbal_check(struct zfcp_qdio *qdio)
@@ -283,6 +303,8 @@ static void zfcp_qdio_setup_init_data(struct qdio_initialize *id,
 	memcpy(id->adapter_name, dev_name(&id->cdev->dev), 8);
 	ASCEBC(id->adapter_name, 8);
 	id->qib_rflags = QIB_RFLAGS_ENABLE_DATA_DIV;
+	if (enable_multibuffer)
+		id->qdr_ac |= QDR_AC_MULTI_BUFFER_ENABLE;
 	id->no_input_qs = 1;
 	id->no_output_qs = 1;
 	id->input_handler = zfcp_qdio_int_resp;
@@ -378,6 +400,17 @@ int zfcp_qdio_open(struct zfcp_qdio *qdio)
 		atomic_set_mask(ZFCP_STATUS_ADAPTER_DATA_DIV_ENABLED,
 				&qdio->adapter->status);
 
+	if (ssqd.qdioac2 & CHSC_AC2_MULTI_BUFFER_ENABLED) {
+		atomic_set_mask(ZFCP_STATUS_ADAPTER_MB_ACT, &adapter->status);
+		qdio->max_sbale_per_sbal = QDIO_MAX_ELEMENTS_PER_BUFFER;
+	} else {
+		atomic_clear_mask(ZFCP_STATUS_ADAPTER_MB_ACT, &adapter->status);
+		qdio->max_sbale_per_sbal = QDIO_MAX_ELEMENTS_PER_BUFFER - 1;
+	}
+
+	qdio->max_sbale_per_req =
+		ZFCP_QDIO_MAX_SBALS_PER_REQ * qdio->max_sbale_per_sbal
+		- 2;
 	if (qdio_activate(cdev))
 		goto failed_qdio;
 
@@ -397,6 +430,11 @@ int zfcp_qdio_open(struct zfcp_qdio *qdio)
 	atomic_set(&qdio->req_q_free, QDIO_MAX_BUFFERS_PER_Q);
 	atomic_set_mask(ZFCP_STATUS_ADAPTER_QDIOUP, &qdio->adapter->status);
 
+	if (adapter->scsi_host) {
+		adapter->scsi_host->sg_tablesize = qdio->max_sbale_per_req;
+		adapter->scsi_host->max_sectors = qdio->max_sbale_per_req * 8;
+	}
+
 	return 0;
 
 failed_qdio:
diff --git a/drivers/s390/scsi/zfcp_qdio.h b/drivers/s390/scsi/zfcp_qdio.h
index 54e22ace012..8ac7f5342d2 100644
--- a/drivers/s390/scsi/zfcp_qdio.h
+++ b/drivers/s390/scsi/zfcp_qdio.h
@@ -13,20 +13,9 @@
 
 #define ZFCP_QDIO_SBALE_LEN	PAGE_SIZE
 
-/* DMQ bug workaround: don't use last SBALE */
-#define ZFCP_QDIO_MAX_SBALES_PER_SBAL	(QDIO_MAX_ELEMENTS_PER_BUFFER - 1)
-
-/* index of last SBALE (with respect to DMQ bug workaround) */
-#define ZFCP_QDIO_LAST_SBALE_PER_SBAL	(ZFCP_QDIO_MAX_SBALES_PER_SBAL - 1)
-
 /* Max SBALS for chaining */
 #define ZFCP_QDIO_MAX_SBALS_PER_REQ	36
 
-/* max. number of (data buffer) SBALEs in largest SBAL chain
- * request ID + QTCB in SBALE 0 + 1 of first SBAL in chain   */
-#define ZFCP_QDIO_MAX_SBALES_PER_REQ     \
-	(ZFCP_QDIO_MAX_SBALS_PER_REQ * ZFCP_QDIO_MAX_SBALES_PER_SBAL - 2)
-
 /**
  * struct zfcp_qdio - basic qdio data structure
  * @res_q: response queue
@@ -53,6 +42,8 @@ struct zfcp_qdio {
 	atomic_t		req_q_full;
 	wait_queue_head_t	req_q_wq;
 	struct zfcp_adapter	*adapter;
+	u16			max_sbale_per_sbal;
+	u16			max_sbale_per_req;
 };
 
 /**
@@ -155,7 +146,7 @@ void zfcp_qdio_fill_next(struct zfcp_qdio *qdio, struct zfcp_qdio_req *q_req,
 {
 	struct qdio_buffer_element *sbale;
 
-	BUG_ON(q_req->sbale_curr == ZFCP_QDIO_LAST_SBALE_PER_SBAL);
+	BUG_ON(q_req->sbale_curr == qdio->max_sbale_per_sbal - 1);
 	q_req->sbale_curr++;
 	sbale = zfcp_qdio_sbale_curr(qdio, q_req);
 	sbale->addr = data;
@@ -195,9 +186,10 @@ int zfcp_qdio_sg_one_sbale(struct scatterlist *sg)
  * @q_req: The current zfcp_qdio_req
  */
 static inline
-void zfcp_qdio_skip_to_last_sbale(struct zfcp_qdio_req *q_req)
+void zfcp_qdio_skip_to_last_sbale(struct zfcp_qdio *qdio,
+				  struct zfcp_qdio_req *q_req)
 {
-	q_req->sbale_curr = ZFCP_QDIO_LAST_SBALE_PER_SBAL;
+	q_req->sbale_curr = qdio->max_sbale_per_sbal - 1;
 }
 
 /**
@@ -228,8 +220,52 @@ void zfcp_qdio_set_data_div(struct zfcp_qdio *qdio,
 {
 	struct qdio_buffer_element *sbale;
 
-	sbale = &qdio->req_q[q_req->sbal_first]->element[0];
+	sbale = qdio->req_q[q_req->sbal_first]->element;
 	sbale->length = count;
 }
 
+/**
+ * zfcp_qdio_sbale_count - count sbale used
+ * @sg: pointer to struct scatterlist
+ */
+static inline
+unsigned int zfcp_qdio_sbale_count(struct scatterlist *sg)
+{
+	unsigned int count = 0;
+
+	for (; sg; sg = sg_next(sg))
+		count++;
+
+	return count;
+}
+
+/**
+ * zfcp_qdio_real_bytes - count bytes used
+ * @sg: pointer to struct scatterlist
+ */
+static inline
+unsigned int zfcp_qdio_real_bytes(struct scatterlist *sg)
+{
+	unsigned int real_bytes = 0;
+
+	for (; sg; sg = sg_next(sg))
+		real_bytes += sg->length;
+
+	return real_bytes;
+}
+
+/**
+ * zfcp_qdio_set_scount - set SBAL count value
+ * @qdio: pointer to struct zfcp_qdio
+ * @q_req: The current zfcp_qdio_req
+ */
+static inline
+void zfcp_qdio_set_scount(struct zfcp_qdio *qdio, struct zfcp_qdio_req *q_req)
+{
+	struct qdio_buffer_element *sbale;
+
+	sbale = qdio->req_q[q_req->sbal_first]->element;
+	sbale->scount = q_req->sbal_number - 1;
+}
+
 #endif /* ZFCP_QDIO_H */
diff --git a/drivers/s390/scsi/zfcp_scsi.c b/drivers/s390/scsi/zfcp_scsi.c
index 96c31a70445..09126a9d62f 100644
--- a/drivers/s390/scsi/zfcp_scsi.c
+++ b/drivers/s390/scsi/zfcp_scsi.c
@@ -306,8 +306,8 @@ static struct scsi_host_template zfcp_scsi_host_template = {
 	.proc_name		 = "zfcp",
 	.can_queue		 = 4096,
 	.this_id		 = -1,
-	.sg_tablesize		 = ZFCP_QDIO_MAX_SBALES_PER_REQ,
-	.max_sectors		 = (ZFCP_QDIO_MAX_SBALES_PER_REQ * 8),
+	.sg_tablesize		 = 1, /* adjusted later */
+	.max_sectors		 = 8, /* adjusted later */
 	.dma_boundary		 = ZFCP_QDIO_SBALE_LEN - 1,
 	.cmd_per_lun		 = 1,
 	.use_clustering		 = 1,
@@ -665,9 +665,9 @@ void zfcp_scsi_set_prot(struct zfcp_adapter *adapter)
 	    adapter->adapter_features & FSF_FEATURE_DIX_PROT_TCPIP) {
 		mask |= SHOST_DIX_TYPE1_PROTECTION;
 		scsi_host_set_guard(shost, SHOST_DIX_GUARD_IP);
-		shost->sg_prot_tablesize = ZFCP_QDIO_MAX_SBALES_PER_REQ / 2;
-		shost->sg_tablesize = ZFCP_QDIO_MAX_SBALES_PER_REQ / 2;
-		shost->max_sectors = ZFCP_QDIO_MAX_SBALES_PER_REQ * 8 / 2;
+		shost->sg_prot_tablesize = adapter->qdio->max_sbale_per_req / 2;
+		shost->sg_tablesize = adapter->qdio->max_sbale_per_req / 2;
+		shost->max_sectors = shost->sg_tablesize * 8;
 	}
 
 	scsi_host_set_prot(shost, mask);