diff --git a/drivers/scsi/libsas/sas_event.c b/drivers/scsi/libsas/sas_event.c
index dbfacee..16639bb 100644
--- a/drivers/scsi/libsas/sas_event.c
+++ b/drivers/scsi/libsas/sas_event.c
@@ -51,15 +51,11 @@ static void sas_queue_event(int event, unsigned long *pending,
 	}
 }
 
-int sas_drain_work(struct sas_ha_struct *ha)
+
+void __sas_drain_work(struct sas_ha_struct *ha)
 {
 	struct workqueue_struct *wq = ha->core.shost->work_q;
 	struct work_struct *w, *_w;
-	int err;
-
-	err = mutex_lock_interruptible(&ha->drain_mutex);
-	if (err)
-		return err;
 
 	set_bit(SAS_HA_DRAINING, &ha->state);
 	/* flush submitters */
@@ -75,6 +71,17 @@ int sas_drain_work(struct sas_ha_struct *ha)
 		sas_queue_work(ha, w);
 	}
 	spin_unlock_irq(&ha->state_lock);
+}
+
+int sas_drain_work(struct sas_ha_struct *ha)
+{
+	int err;
+
+	err = mutex_lock_interruptible(&ha->drain_mutex);
+	if (err)
+		return err;
+	if (test_bit(SAS_HA_REGISTERED, &ha->state))
+		__sas_drain_work(ha);
 	mutex_unlock(&ha->drain_mutex);
 
 	return 0;
diff --git a/drivers/scsi/libsas/sas_init.c b/drivers/scsi/libsas/sas_init.c
index dc93e118..09c14ca 100644
--- a/drivers/scsi/libsas/sas_init.c
+++ b/drivers/scsi/libsas/sas_init.c
@@ -160,18 +160,22 @@ Undo_phys:
 
 int sas_unregister_ha(struct sas_ha_struct *sas_ha)
 {
-	unsigned long flags;
-
 	/* Set the state to unregistered to avoid further unchained
-	 * events to be queued
+	 * events to be queued, and flush any in-progress drainers
 	 */
-	spin_lock_irqsave(&sas_ha->state_lock, flags);
+	mutex_lock(&sas_ha->drain_mutex);
+	spin_lock_irq(&sas_ha->state_lock);
 	clear_bit(SAS_HA_REGISTERED, &sas_ha->state);
-	spin_unlock_irqrestore(&sas_ha->state_lock, flags);
-	sas_drain_work(sas_ha);
+	spin_unlock_irq(&sas_ha->state_lock);
+	__sas_drain_work(sas_ha);
+	mutex_unlock(&sas_ha->drain_mutex);
 
 	sas_unregister_ports(sas_ha);
-	sas_drain_work(sas_ha);
+
+	/* flush unregistration work */
+	mutex_lock(&sas_ha->drain_mutex);
+	__sas_drain_work(sas_ha);
+	mutex_unlock(&sas_ha->drain_mutex);
 
 	if (sas_ha->lldd_max_execute_num > 1) {
 		sas_shutdown_queue(sas_ha);
diff --git a/drivers/scsi/libsas/sas_internal.h b/drivers/scsi/libsas/sas_internal.h
index 4157f6e..7818c46 100644
--- a/drivers/scsi/libsas/sas_internal.h
+++ b/drivers/scsi/libsas/sas_internal.h
@@ -70,6 +70,7 @@ int  sas_init_events(struct sas_ha_struct *sas_ha);
 void sas_shutdown_queue(struct sas_ha_struct *sas_ha);
 void sas_disable_revalidation(struct sas_ha_struct *ha);
 void sas_enable_revalidation(struct sas_ha_struct *ha);
+void __sas_drain_work(struct sas_ha_struct *ha);
 
 void sas_deform_port(struct asd_sas_phy *phy, int gone);