net/mlx5: Fix mlx5_get_uars_page to return error code

Change mlx5_get_uars_page to return ERR_PTR in case of
allocation failure. Change all callers accordingly to
check the IS_ERR(ptr) instead of NULL.

Fixes: 59211bd3b6 ("net/mlx5: Split the load/unload flow into hardware and software flows")
Signed-off-by: Eran Ben Elisha <eranbe@mellanox.com>
Signed-off-by: Eugenia Emantayev <eugenia@mellanox.com>
Signed-off-by: Saeed Mahameed <saeedm@mellanox.com>

drivers/infiniband/hw/mlx5/main.c

@@ -4160,7 +4160,7 @@ static void *mlx5_ib_add(struct mlx5_core_dev *mdev)
 		goto err_cnt;
 
 	dev->mdev->priv.uar = mlx5_get_uars_page(dev->mdev);
-	if (!dev->mdev->priv.uar)
+	if (IS_ERR(dev->mdev->priv.uar))
 		goto err_cong;
 
 	err = mlx5_alloc_bfreg(dev->mdev, &dev->bfreg, false, false);

drivers/net/ethernet/mellanox/mlx5/core/main.c

@@ -1135,8 +1135,9 @@ static int mlx5_load_one(struct mlx5_core_dev *dev, struct mlx5_priv *priv,
 	}
 
 	dev->priv.uar = mlx5_get_uars_page(dev);
-	if (!dev->priv.uar) {
+	if (IS_ERR(dev->priv.uar)) {
 		dev_err(&pdev->dev, "Failed allocating uar, aborting\n");
+		err = PTR_ERR(dev->priv.uar);
 		goto err_disable_msix;
 	}
 

drivers/net/ethernet/mellanox/mlx5/core/uar.c

@@ -168,18 +168,16 @@ struct mlx5_uars_page *mlx5_get_uars_page(struct mlx5_core_dev *mdev)
 	struct mlx5_uars_page *ret;
 
 	mutex_lock(&mdev->priv.bfregs.reg_head.lock);
-	if (list_empty(&mdev->priv.bfregs.reg_head.list)) {
-		ret = alloc_uars_page(mdev, false);
-		if (IS_ERR(ret)) {
-			ret = NULL;
-			goto out;
-		}
-		list_add(&ret->list, &mdev->priv.bfregs.reg_head.list);
-	} else {
+	if (!list_empty(&mdev->priv.bfregs.reg_head.list)) {
 		ret = list_first_entry(&mdev->priv.bfregs.reg_head.list,
 				       struct mlx5_uars_page, list);
 		kref_get(&ret->ref_count);
+		goto out;
 	}
+	ret = alloc_uars_page(mdev, false);
+	if (IS_ERR(ret))
+		goto out;
+	list_add(&ret->list, &mdev->priv.bfregs.reg_head.list);
 out:
 	mutex_unlock(&mdev->priv.bfregs.reg_head.lock);