[SCSI] zfcp: Fix deadlock between zfcp ERP and SCSI

[linux-2.6] / drivers / s390 / scsi / zfcp_erp.c

diff --git a/drivers/s390/scsi/zfcp_erp.c b/drivers/s390/scsi/zfcp_erp.c
index f326bbe49fa75d2d2e73dc88090f199f061451b0..885572300589df157348fd7a97147c1122e7fe81 100644 (file)
--- 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;