diff --git a/drivers/infiniband/hw/mthca/mthca_uar.c b/drivers/infiniband/hw/mthca/mthca_uar.c
index 8e9219842be4..8b728486410d 100644
--- a/drivers/infiniband/hw/mthca/mthca_uar.c
+++ b/drivers/infiniband/hw/mthca/mthca_uar.c
@@ -60,7 +60,7 @@ int mthca_init_uar_table(struct mthca_dev *dev)
 	ret = mthca_alloc_init(&dev->uar_table.alloc,
 			       dev->limits.num_uars,
 			       dev->limits.num_uars - 1,
-			       dev->limits.reserved_uars);
+			       dev->limits.reserved_uars + 1);
 	if (ret)
 		return ret;