diff --git a/drivers/s390/scsi/zfcp_fsf.c b/drivers/s390/scsi/zfcp_fsf.c
index 3376305609f9d02aabf86fd5c4e54c3c3267de82..878b8f86ddc7bd013308e54968e44585f19c3b80 100644
--- a/drivers/s390/scsi/zfcp_fsf.c
+++ b/drivers/s390/scsi/zfcp_fsf.c
@@ -644,38 +644,38 @@ static void zfcp_fsf_exchange_port_data_handler(struct zfcp_fsf_req *req)
 	}
 }
 
-static int zfcp_fsf_sbal_check(struct zfcp_adapter *adapter)
+static int zfcp_fsf_sbal_available(struct zfcp_adapter *adapter)
 {
-	struct zfcp_qdio_queue *req_q = &adapter->req_q;
-
-	spin_lock_bh(&adapter->req_q_lock);
-	if (atomic_read(&req_q->count))
+	if (atomic_read(&adapter->req_q.count) > 0)
 		return 1;
-	spin_unlock_bh(&adapter->req_q_lock);
+	atomic_inc(&adapter->qdio_outb_full);
 	return 0;
 }
 
-static int zfcp_fsf_sbal_available(struct zfcp_adapter *adapter)
-{
-	unsigned int count = atomic_read(&adapter->req_q.count);
-	if (!count)
-		atomic_inc(&adapter->qdio_outb_full);
-	return count > 0;
-}
-
 static int zfcp_fsf_req_sbal_get(struct zfcp_adapter *adapter)
+	__releases(&adapter->req_q_lock)
+	__acquires(&adapter->req_q_lock)
 {
+	struct zfcp_qdio_queue *req_q = &adapter->req_q;
 	long ret;
 
+	if (atomic_read(&req_q->count) <= -REQUEST_LIST_SIZE)
+		return -EIO;
+	if (atomic_read(&req_q->count) > 0)
+		return 0;
+
+	atomic_dec(&req_q->count);
 	spin_unlock_bh(&adapter->req_q_lock);
 	ret = wait_event_interruptible_timeout(adapter->request_wq,
-					zfcp_fsf_sbal_check(adapter), 5 * HZ);
+					atomic_read(&req_q->count) >= 0,
+					5 * HZ);
+	spin_lock_bh(&adapter->req_q_lock);
+	atomic_inc(&req_q->count);
+
 	if (ret > 0)
 		return 0;
 	if (!ret)
 		atomic_inc(&adapter->qdio_outb_full);
-
-	spin_lock_bh(&adapter->req_q_lock);
 	return -EIO;
 }