mlx4: Handle memory region deregistration failure

Memory region deregistration can fail when memory windows
are bound to it. We handle such failures by propagating them
to the user, or by printing a serious warning.

Signed-off-by: Haggai Eran <[email protected]>
Signed-off-by: Shani Michaeli <[email protected]>
(Ported from Mellanox OFED 2.4)

Signed-off-by: Mukesh Kacker <[email protected]>

Author: Shani Michaeli

drivers/infiniband/core/uverbs_main.c

@@ -199,6 +199,7 @@ static int ib_uverbs_cleanup_ucontext(struct ib_uverbs_file *file,
 				      struct ib_ucontext *context)
 {
 	struct ib_uobject *uobj, *tmp;
+	int err;
 
 	if (!context)
 		return 0;
@@ -273,7 +274,11 @@ static int ib_uverbs_cleanup_ucontext(struct ib_uverbs_file *file,
 		struct ib_mr *mr = uobj->object;
 
 		idr_remove_uobj(&ib_uverbs_mr_idr, uobj);
-		ib_dereg_mr(mr);
+		err = ib_dereg_mr(mr);
+		if (err) {
+			pr_info("user_verbs: couldn't deregister an MR during cleanup.\n");
+			pr_info("user_verbs: the system may have become unstable.\n");
+		}
 		kfree(uobj);
 	}
 

drivers/net/ethernet/mellanox/mlx4/en_main.c

@@ -200,7 +200,7 @@ static void mlx4_en_event(struct mlx4_dev *dev, void *endev_ptr,
 static void mlx4_en_remove(struct mlx4_dev *dev, void *endev_ptr)
 {
 	struct mlx4_en_dev *mdev = endev_ptr;
-	int i;
+	int i, ret;
 
 	mutex_lock(&mdev->state_lock);
 	mdev->device_up = false;
@@ -215,7 +215,9 @@ static void mlx4_en_remove(struct mlx4_dev *dev, void *endev_ptr)
 
 	flush_workqueue(mdev->workqueue);
 	destroy_workqueue(mdev->workqueue);
-	(void) mlx4_mr_free(dev, &mdev->mr);
+	ret = mlx4_mr_free(dev, &mdev->mr);
+	if (ret)
+		mlx4_err(mdev, "Error deregistering MR. The system may have become unstable.");
 	iounmap(mdev->uar_map);
 	mlx4_uar_free(dev, &mdev->priv_uar);
 	mlx4_pd_free(dev, mdev->priv_pdn);
@@ -315,7 +317,8 @@ static void *mlx4_en_add(struct mlx4_dev *dev)
 	return mdev;
 
 err_mr:
-	(void) mlx4_mr_free(dev, &mdev->mr);
+	if (mlx4_mr_free(dev, &mdev->mr))
+		mlx4_err(mdev, "Error deregistering MR. The system may have become unstable.");
 err_map:
 	if (mdev->uar_map)
 		iounmap(mdev->uar_map);

drivers/net/ethernet/mellanox/mlx4/mr.c

@@ -1050,7 +1050,7 @@ int mlx4_fmr_alloc(struct mlx4_dev *dev, u32 pd, u32 access, int max_pages,
 		   int max_maps, u8 page_shift, struct mlx4_fmr *fmr)
 {
 	struct mlx4_priv *priv = mlx4_priv(dev);
-	int err = -ENOMEM;
+	int err = -ENOMEM, ret;
 
 	if (max_maps > dev->caps.max_fmr_maps)
 		return -EINVAL;
@@ -1084,7 +1084,9 @@ int mlx4_fmr_alloc(struct mlx4_dev *dev, u32 pd, u32 access, int max_pages,
 	return 0;
 
 err_free:
-	(void) mlx4_mr_free(dev, &fmr->mr);
+	ret = mlx4_mr_free(dev, &fmr->mr);
+	if (ret)
+		mlx4_err(dev, "Error deregistering MR. The system may have become unstable.");
 	return err;
 }
 EXPORT_SYMBOL_GPL(mlx4_fmr_alloc);