diff --git a/drivers/infiniband/hw/mlx5/mr.c b/drivers/infiniband/hw/mlx5/mr.c
index 231b043e2806..000937fe53ec 100644
--- a/drivers/infiniband/hw/mlx5/mr.c
+++ b/drivers/infiniband/hw/mlx5/mr.c
@@ -1813,7 +1813,6 @@ mlx5_ib_sg_to_klms(struct mlx5_ib_mr *mr,
 
 	mr->ibmr.iova = sg_dma_address(sg) + sg_offset;
 	mr->ibmr.length = 0;
-	mr->ndescs = sg_nents;
 
 	for_each_sg(sgl, sg, sg_nents, i) {
 		if (unlikely(i >= mr->max_descs))
@@ -1825,6 +1824,7 @@ mlx5_ib_sg_to_klms(struct mlx5_ib_mr *mr,
 
 		sg_offset = 0;
 	}
+	mr->ndescs = i;
 
 	if (sg_offset_p)
 		*sg_offset_p = sg_offset;