Re: [Qemu-devel] [PATCH v2 1/6] pci: Clean up error checking in pci_add_capability()

["Michael S. Tsirkin" <mst@redhat.com>]

On Fri, Jun 02, 2017 at 03:54:37PM +0800, Mao Zhongyi wrote:
> On success, pci_add_capability2() returns a positive value. On
> failure, it sets an error and return a negative value.
> 
> pci_add_capability() laboriously checks this behavior. No other
> caller does. Drop the checks from pci_add_capability().
> 
> Cc: mst@redhat.com
> Cc: marcel@redhat.com
> Cc: armbru@redhat.com
> Signed-off-by: Mao Zhongyi <maozy.fnst@cn.fujitsu.com>
> Reviewed-by: Marcel Apfelbaum <marcel@redhat.com>
> ---
>  hw/pci/pci.c | 6 +-----
>  1 file changed, 1 insertion(+), 5 deletions(-)
> 
> diff --git a/hw/pci/pci.c b/hw/pci/pci.c
> index 98ccc27..53566b8 100644
> --- a/hw/pci/pci.c
> +++ b/hw/pci/pci.c
> @@ -2270,12 +2270,8 @@ int pci_add_capability(PCIDevice *pdev, uint8_t cap_id,
>      Error *local_err = NULL;
>  
>      ret = pci_add_capability2(pdev, cap_id, offset, size, &local_err);
> -    if (local_err) {
> -        assert(ret < 0);
> +    if (ret < 0) {
>          error_report_err(local_err);
> -    } else {
> -        /* success implies a positive offset in config space */
> -        assert(ret > 0);
>      }
>      return ret;
>  }


I don't see why this is a good idea. You drop a bunch of
asserts, so naturally code is slightly tighter. We could gain
the same by building with NDEBUG but we don't, we rather
have more safety.

> -- 
> 2.9.3
> 
> 
>