4 files changed, 72 insertions, 4 deletions

diff --git a/drivers/s390/scsi/zfcp_aux.c b/drivers/s390/scsi/zfcp_aux.c
index ec3f664f6c80..49d5fc729bef 100644
--- a/drivers/s390/scsi/zfcp_aux.c
+++ b/drivers/s390/scsi/zfcp_aux.c
@@ -913,6 +913,8 @@ zfcp_unit_enqueue(struct zfcp_port *port, fcp_lun_t fcp_lun)
 	unit->sysfs_device.release = zfcp_sysfs_unit_release;
 	dev_set_drvdata(&unit->sysfs_device, unit);
 
+	init_waitqueue_head(&unit->scsi_scan_wq);
+
 	/* mark unit unusable as long as sysfs registration is not complete */
 	atomic_set_mask(ZFCP_STATUS_COMMON_REMOVE, &unit->status);
 
diff --git a/drivers/s390/scsi/zfcp_def.h b/drivers/s390/scsi/zfcp_def.h
index 32933ed54b8a..07b0957b82f3 100644
--- a/drivers/s390/scsi/zfcp_def.h
+++ b/drivers/s390/scsi/zfcp_def.h
@@ -637,6 +637,7 @@ do { \
 #define ZFCP_STATUS_UNIT_SHARED			0x00000004
 #define ZFCP_STATUS_UNIT_READONLY		0x00000008
 #define ZFCP_STATUS_UNIT_REGISTERED		0x00000010
+#define ZFCP_STATUS_UNIT_SCSI_WORK_PENDING	0x00000020
 
 /* FSF request status (this does not have a common part) */
 #define ZFCP_STATUS_FSFREQ_NOT_INIT		0x00000000
@@ -980,6 +981,10 @@ struct zfcp_unit {
         struct scsi_device     *device;        /* scsi device struct pointer */
 	struct zfcp_erp_action erp_action;     /* pending error recovery */
         atomic_t               erp_counter;
+	wait_queue_head_t      scsi_scan_wq;   /* can be used to wait until
+						  all scsi_scan_target
+						  requests have been
+						  completed. */
 };
 
 /* FSF request */
diff --git a/drivers/s390/scsi/zfcp_erp.c b/drivers/s390/scsi/zfcp_erp.c
index f326bbe49fa7..885572300589 100644
--- a/drivers/s390/scsi/zfcp_erp.c
+++ b/drivers/s390/scsi/zfcp_erp.c
@@ -1591,6 +1591,62 @@ zfcp_erp_strategy_check_adapter(struct zfcp_adapter *adapter, int result)
 	return result;
 }
 
+struct zfcp_erp_add_work {
+	struct zfcp_unit  *unit;
+	struct work_struct work;
+};
+
+/**
+ * zfcp_erp_scsi_scan
+ * @data: pointer to a struct zfcp_erp_add_work
+ *
+ * Registers a logical unit with the SCSI stack.
+ */
+static void zfcp_erp_scsi_scan(struct work_struct *work)
+{
+	struct zfcp_erp_add_work *p =
+		container_of(work, struct zfcp_erp_add_work, work);
+	struct zfcp_unit *unit = p->unit;
+	struct fc_rport *rport = unit->port->rport;
+	scsi_scan_target(&rport->dev, 0, rport->scsi_target_id,
+			 unit->scsi_lun, 0);
+	atomic_clear_mask(ZFCP_STATUS_UNIT_SCSI_WORK_PENDING, &unit->status);
+	wake_up(&unit->scsi_scan_wq);
+	zfcp_unit_put(unit);
+	kfree(p);
+}
+
+/**
+ * zfcp_erp_schedule_work
+ * @unit: pointer to unit which should be registered with SCSI stack
+ *
+ * Schedules work which registers a unit with the SCSI stack
+ */
+static void
+zfcp_erp_schedule_work(struct zfcp_unit *unit)
+{
+	struct zfcp_erp_add_work *p;
+
+	p = kmalloc(sizeof(*p), GFP_KERNEL);
+	if (!p) {
+		ZFCP_LOG_NORMAL("error: Out of resources. Could not register "
+				"the FCP-LUN 0x%Lx connected to "
+				"the port with WWPN 0x%Lx connected to "
+				"the adapter %s with the SCSI stack.\n",
+				unit->fcp_lun,
+				unit->port->wwpn,
+				zfcp_get_busid_by_unit(unit));
+		return;
+	}
+
+	zfcp_unit_get(unit);
+	memset(p, 0, sizeof(*p));
+	atomic_set_mask(ZFCP_STATUS_UNIT_SCSI_WORK_PENDING, &unit->status);
+	INIT_WORK(&p->work, zfcp_erp_scsi_scan);
+	p->unit = unit;
+	schedule_work(&p->work);
+}
+
 /*
  * function:	
  *
@@ -3092,9 +3148,9 @@ zfcp_erp_action_cleanup(int action, struct zfcp_adapter *adapter,
 		    && port->rport) {
 			atomic_set_mask(ZFCP_STATUS_UNIT_REGISTERED,
 					&unit->status);
- 			scsi_scan_target(&port->rport->dev, 0,
-					 port->rport->scsi_target_id,
-					 unit->scsi_lun, 0);
+			if (atomic_test_mask(ZFCP_STATUS_UNIT_SCSI_WORK_PENDING,
+					     &unit->status) == 0)
+				zfcp_erp_schedule_work(unit);
 		}
 		zfcp_unit_put(unit);
 		break;
@@ -3121,7 +3177,7 @@ zfcp_erp_action_cleanup(int action, struct zfcp_adapter *adapter,
 						zfcp_get_busid_by_port(port),
 						port->wwpn);
 			else {
-				scsi_flush_work(adapter->scsi_host);
+				scsi_target_unblock(&port->rport->dev);
 				port->rport->maxframe_size = port->maxframe_size;
 				port->rport->supported_classes =
 					port->supported_classes;
diff --git a/drivers/s390/scsi/zfcp_scsi.c b/drivers/s390/scsi/zfcp_scsi.c
index 99db02062c3b..e742b3de16ac 100644
--- a/drivers/s390/scsi/zfcp_scsi.c
+++ b/drivers/s390/scsi/zfcp_scsi.c
@@ -22,6 +22,7 @@
 #define ZFCP_LOG_AREA			ZFCP_LOG_AREA_SCSI
 
 #include "zfcp_ext.h"
+#include <asm/atomic.h>
 
 static void zfcp_scsi_slave_destroy(struct scsi_device *sdp);
 static int zfcp_scsi_slave_alloc(struct scsi_device *sdp);
@@ -179,6 +180,10 @@ static void zfcp_scsi_slave_destroy(struct scsi_device *sdpnt)
 	struct zfcp_unit *unit = (struct zfcp_unit *) sdpnt->hostdata;
 
 	if (unit) {
+		zfcp_erp_wait(unit->port->adapter);
+		wait_event(unit->scsi_scan_wq,
+			   atomic_test_mask(ZFCP_STATUS_UNIT_SCSI_WORK_PENDING,
+					    &unit->status) == 0);
 		atomic_clear_mask(ZFCP_STATUS_UNIT_REGISTERED, &unit->status);
 		sdpnt->hostdata = NULL;
 		unit->device = NULL;