RDMA/mlx4: Use bitmap_alloc() when applicable

Use 'bitmap_alloc()' to simplify code, improve the semantic and avoid some
open-coded arithmetic in allocator arguments.

Also change the corresponding 'kfree()' into 'bitmap_free()' to keep
consistency.

Link: https://lore.kernel.org/r/4c93b4e02f5d784ddfd3efd4af9e673b9117d641.1637869328.git.christophe.jaillet@wanadoo.frSigned-off-by: Christophe JAILLET <christophe.jaillet@wanadoo.fr>
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>

drivers/infiniband/hw/mlx4/main.c

@@ -2772,10 +2772,8 @@ static void *mlx4_ib_add(struct mlx4_dev *dev)
 		if (err)
 			goto err_counter;
 
-		ibdev->ib_uc_qpns_bitmap =
-			kmalloc_array(BITS_TO_LONGS(ibdev->steer_qpn_count),
-				      sizeof(long),
-				      GFP_KERNEL);
+		ibdev->ib_uc_qpns_bitmap = bitmap_alloc(ibdev->steer_qpn_count,
+							GFP_KERNEL);
 		if (!ibdev->ib_uc_qpns_bitmap)
 			goto err_steer_qp_release;
 
@@ -2863,7 +2861,7 @@ static void *mlx4_ib_add(struct mlx4_dev *dev)
 	mlx4_ib_diag_cleanup(ibdev);
 
 err_steer_free_bitmap:
-	kfree(ibdev->ib_uc_qpns_bitmap);
+	bitmap_free(ibdev->ib_uc_qpns_bitmap);
 
 err_steer_qp_release:
 	mlx4_qp_release_range(dev, ibdev->steer_qpn_base,
@@ -2976,7 +2974,7 @@ static void mlx4_ib_remove(struct mlx4_dev *dev, void *ibdev_ptr)
 
 	mlx4_qp_release_range(dev, ibdev->steer_qpn_base,
 			      ibdev->steer_qpn_count);
-	kfree(ibdev->ib_uc_qpns_bitmap);
+	bitmap_free(ibdev->ib_uc_qpns_bitmap);
 
 	iounmap(ibdev->uar_map);
 	for (p = 0; p < ibdev->num_ports; ++p)