[SCSI] zfcp: Use status_read_buf_num provided by FCP channel

The FCP channel provides the number of status read buffers to issue.
Use the provided number instead of the hardcoded number in zfcp.
Reviewed-by: Swen Schillig <swen@vnet.ibm.com>
Signed-off-by: Christof Schmitt <christof.schmitt@de.ibm.com>
Signed-off-by: James Bottomley <James.Bottomley@suse.de>

drivers/s390/scsi/zfcp_aux.c

@@ -425,7 +425,8 @@ int zfcp_status_read_refill(struct zfcp_adapter *adapter)
 {
 	while (atomic_read(&adapter->stat_miss) > 0)
 		if (zfcp_fsf_status_read(adapter->qdio)) {
-			if (atomic_read(&adapter->stat_miss) >= 16) {
+			if (atomic_read(&adapter->stat_miss) >=
+			    adapter->stat_read_buf_num) {
 				zfcp_erp_adapter_reopen(adapter, 0, "axsref1",
 							NULL);
 				return 1;

drivers/s390/scsi/zfcp_def.h

@@ -164,6 +164,7 @@ struct zfcp_adapter {
 						      stack abort/command
 						      completion races */
 	atomic_t		stat_miss;	   /* # missing status reads*/
+	unsigned int		stat_read_buf_num;
 	struct work_struct	stat_work;
 	atomic_t		status;	           /* status of this adapter */
 	struct list_head	erp_ready_head;	   /* error recovery for this

drivers/s390/scsi/zfcp_erp.c

@@ -714,7 +714,7 @@ static int zfcp_erp_adapter_strategy_open_fsf(struct zfcp_erp_action *act)
 	if (zfcp_erp_adapter_strategy_open_fsf_xport(act) == ZFCP_ERP_FAILED)
 		return ZFCP_ERP_FAILED;
 
-	atomic_set(&act->adapter->stat_miss, 16);
+	atomic_set(&act->adapter->stat_miss, act->adapter->stat_read_buf_num);
 	if (zfcp_status_read_refill(act->adapter))
 		return ZFCP_ERP_FAILED;
 

drivers/s390/scsi/zfcp_fsf.c

@@ -496,6 +496,7 @@ static int zfcp_fsf_exchange_config_evaluate(struct zfcp_fsf_req *req)
 
 	adapter->hydra_version = bottom->adapter_type;
 	adapter->timer_ticks = bottom->timer_interval;
+	adapter->stat_read_buf_num = max(bottom->status_read_buf_num, (u16)16);
 
 	if (fc_host_permanent_port_name(shost) == -1)
 		fc_host_permanent_port_name(shost) = fc_host_port_name(shost);

drivers/s390/scsi/zfcp_fsf.h

@@ -366,7 +366,7 @@ struct fsf_qtcb_bottom_config {
 	u32 adapter_type;
 	u8 res0;
 	u8 peer_d_id[3];
-	u8 res1[2];
+	u16 status_read_buf_num;
 	u16 timer_interval;
 	u8 res2[9];
 	u8 s_id[3];