Merge tag 'for-gkh' of git://git.kernel.org/pub/scm/linux/kernel/git/…

…rdma/rdma

Doug writes:
  "RDMA fixes:

   Final for-rc pull request for 4.19

   We only have one bug to submit this time around.  It fixes a DMA
   unmap issue where we unmapped the DMA address from the IOMMU before
   we did from the card, resulting in a DMAR error with IOMMU enabled,
   or possible crash without."

* tag 'for-gkh' of git://git.kernel.org/pub/scm/linux/kernel/git/rdma/rdma:
  IB/mlx5: Unmap DMA addr from HCA before IOMMU

drivers/infiniband/hw/mlx5/mr.c

@@ -544,6 +544,9 @@ void mlx5_mr_cache_free(struct mlx5_ib_dev *dev, struct mlx5_ib_mr *mr)
 	int shrink = 0;
 	int c;
 
+	if (!mr->allocated_from_cache)
+		return;
+
 	c = order2idx(dev, mr->order);
 	if (c < 0 || c >= MAX_MR_CACHE_ENTRIES) {
 		mlx5_ib_warn(dev, "order %d, cache index %d\n", mr->order, c);
@@ -1647,18 +1650,19 @@ static void dereg_mr(struct mlx5_ib_dev *dev, struct mlx5_ib_mr *mr)
 		umem = NULL;
 	}
 #endif
-
 	clean_mr(dev, mr);
 
+	/*
+	 * We should unregister the DMA address from the HCA before
+	 * remove the DMA mapping.
+	 */
+	mlx5_mr_cache_free(dev, mr);
 	if (umem) {
 		ib_umem_release(umem);
 		atomic_sub(npages, &dev->mdev->priv.reg_pages);
 	}
-
 	if (!mr->allocated_from_cache)
 		kfree(mr);
-	else
-		mlx5_mr_cache_free(dev, mr);
 }
 
 int mlx5_ib_dereg_mr(struct ib_mr *ibmr)