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;