Re: [PATCH] vfio: check vfio_register_iommu_driver() return value

From: Alex Williamson
Date: Tue Jun 21 2022 - 13:32:34 EST


On Tue, 21 Jun 2022 02:21:12 -0400
Bo Liu <liubo03@xxxxxxxxxx> wrote:

> As vfio_register_iommu_driver() can fail, we should check the return value.
>
> Signed-off-by: Bo Liu <liubo03@xxxxxxxxxx>
> ---
> drivers/vfio/vfio.c | 8 +++++++-
> 1 file changed, 7 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/vfio/vfio.c b/drivers/vfio/vfio.c
> index 61e71c1154be..7d4b6dfafd27 100644
> --- a/drivers/vfio/vfio.c
> +++ b/drivers/vfio/vfio.c
> @@ -2159,10 +2159,16 @@ static int __init vfio_init(void)
> pr_info(DRIVER_DESC " version: " DRIVER_VERSION "\n");

If we're going to acknowledge that the below can fail, then we should
move the pr_info so that we only advertise that vfio has loaded after
all potential failure points.

>
> #ifdef CONFIG_VFIO_NOIOMMU
> - vfio_register_iommu_driver(&vfio_noiommu_ops);
> + ret = vfio_register_iommu_driver(&vfio_noiommu_ops);
> + if (ret)
> + goto err_driver_register;
> #endif

We could move this #endif above the ret test so that the goto exists
outside of the #ifdef, then we don't need to wrap the goto target in
#ifdefs below. Thanks,

Alex

> return 0;
>
> +#ifdef CONFIG_VFIO_NOIOMMU
> +err_driver_register:
> + unregister_chrdev_region(vfio.group_devt, MINORMASK + 1);
> +#endif
> err_alloc_chrdev:
> class_destroy(vfio.class);
> vfio.class = NULL;