RE: [PATCH v2 00/11] VFIO: misc cleanups

["Duan, Zhenzhong" <zhenzhong.duan@intel.com>]

Hi All,

When I looked into more functions passing 'Error **',
I see many are in "int testfunc(..., Error **errp)" format. I was a bit confused.

The qapi/error.h suggests:

* - Whenever practical, also return a value that indicates success /
 *   failure.  This can make the error checking more concise, and can
 *   avoid useless error object creation and destruction.  Note that
 *   we still have many functions returning void.  We recommend
 *   • bool-valued functions return true on success / false on failure,
 *   • pointer-valued functions return non-null / null pointer, and
 *   • integer-valued functions return non-negative / negative.

There are some functions like:

int testfunc(..., Error **errp)
{
    If (succeed) {
        return 0;
    } else {
        return -EINVAL;
    }
}

Does testfunc() follow 'integer-valued functions' as above or it should be changed to 'bool-valued functions'?

Is there a clear rule in which case to change 'int testfunc(... Error **errp)' to ' bool testfunc(... Error **errp)'?

Thanks
Zhenzhong

>-----Original Message-----
>From: Duan, Zhenzhong <zhenzhong.duan@intel.com>
><zhenzhong.duan@intel.com>
>Subject: [PATCH v2 00/11] VFIO: misc cleanups
>
>Hi
>
>This is a cleanup series to change functions in hw/vfio/ to return bool
>when the error is passed through errp parameter, also some cleanup
>with g_autofree.
>
>See discussion at https://lists.gnu.org/archive/html/qemu-devel/2024-
>04/msg04782.html
>
>This series processed below files:
>hw/vfio/container.c
>hw/vfio/iommufd.c
>hw/vfio/cpr.c
>backends/iommufd.c
>
>So above files are clean now, there are still other files need processing
>in hw/vfio.
>
>Test done on x86 platform:
>vfio device hotplug/unplug with different backend
>reboot
>
>Thanks
>Zhenzhong
>
>Changelog:
>v2:
>- split out g_autofree code as a patch (Cédric)
>- add processing for more files
>
>Zhenzhong Duan (11):
>  vfio/pci: Use g_autofree in vfio_realize
>  vfio/pci: Use g_autofree in iommufd_cdev_get_info_iova_range()
>  vfio: Make VFIOIOMMUClass::attach_device() and its wrapper return bool
>  vfio: Make VFIOIOMMUClass::setup() return bool
>  vfio: Make VFIOIOMMUClass::add_window() and its wrapper return bool
>  vfio/container: Make vfio_connect_container() return bool
>  vfio/container: Make vfio_set_iommu() return bool
>  vfio/container: Make vfio_get_device() return bool
>  vfio/iommufd: Make iommufd_cdev_*() return bool
>  vfio/cpr: Make vfio_cpr_register_container() return bool
>  backends/iommufd: Make iommufd_backend_*() return bool
>
> include/hw/vfio/vfio-common.h         |   6 +-
> include/hw/vfio/vfio-container-base.h |  18 ++---
> include/sysemu/iommufd.h              |   6 +-
> backends/iommufd.c                    |  29 +++----
> hw/vfio/ap.c                          |   6 +-
> hw/vfio/ccw.c                         |   6 +-
> hw/vfio/common.c                      |   6 +-
> hw/vfio/container-base.c              |   8 +-
> hw/vfio/container.c                   |  81 +++++++++----------
> hw/vfio/cpr.c                         |   4 +-
> hw/vfio/iommufd.c                     | 109 +++++++++++---------------
> hw/vfio/pci.c                         |  12 ++-
> hw/vfio/platform.c                    |   7 +-
> hw/vfio/spapr.c                       |  28 +++----
> backends/trace-events                 |   4 +-
> 15 files changed, 147 insertions(+), 183 deletions(-)
>
>--
>2.34.1