Re: [PATCH v3 02/12] domain_driver: extract DetachXXXDeviceConfig related functions and use them

On Wed, Nov 10, 2021 at 10:24:21PM +0800, Luke Yue wrote: > libxl / lxc / qemu drivers share some common codes in their > DomainDetachDeviceConfig functions, so extract them to > domain_driver and > reuse them. > I would argue that these specific functions are actually dealing just with the domain definition which is done mostly in domain_conf.c, so I would pick that place.

> At the same time, this will enable test driver to test these > functions > with virshtest in the future. > > Signed-off-by: Luke Yue <lukedyue(a)gmail.com&gt; > --- > Not pretty sure whether this is a proper way to make these > functions > reusable, maybe there is a more elegant choice. The patch does a good job in deduplicating some of the code and except the file placement I think the overall approach is fine. However unfortunately the functions are just copy-paste from various places and they could be cleaned up to look the same.  For example... > --- > src/hypervisor/domain_driver.c | 266 > +++++++++++++++++++++++++++++++++ > src/hypervisor/domain_driver.h |  41 +++++ > src/libvirt_private.syms       |  14 ++ > src/libxl/libxl_driver.c       |  41 +---- > src/lxc/lxc_driver.c           |  37 +---- > src/qemu/qemu_driver.c         | 123 +++------------ > 6 files changed, 356 insertions(+), 166 deletions(-) > > diff --git a/src/hypervisor/domain_driver.c > b/src/hypervisor/domain_driver.c > index 31737b0f4a..01ecb4e30e 100644 > --- a/src/hypervisor/domain_driver.c > +++ b/src/hypervisor/domain_driver.c > @@ -644,3 +644,269 @@ > virDomainDriverGetIOThreadsConfig(virDomainDef *targetDef, > >     return ret; > } > + > + > +int > +virDomainDriverDetachDiskDeviceConfig(virDomainDef *vmdef, > +                                      virDomainDeviceDef *dev) > +{ > +    virDomainDiskDef *disk; > +    virDomainDiskDef *det_disk; > + > +    disk = dev->data.disk; > +    if (!(det_disk = virDomainDiskRemoveByName(vmdef, disk->dst))) > { > +        virReportError(VIR_ERR_DEVICE_MISSING, _("no target device > %s"), > +                       disk->dst); > +        return -1; > +    } > +    virDomainDiskDefFree(det_disk); > + > +    return 0; This function uses temporary variables for everything and adds an error message (which could be moved to the virDomainDiskRemoveByName() as all callers do report the same error message when it is not found.  Other functions do essentially the same job, but have random comments, some have extra helper variables. All that could be nicely unified and it would read so much nicer. What I really like about this change is that apart from roughly two device types, like video and chardev, this function could be de-duplicated as well.  Adding a new functionality to that de- duplicated function would then add that functionality into all the drivers using this function.  Of course the special devices would need some xmlopt callbacks or something that drivers can modify themselves for such reasons, but such change would be really, really helpful, especially in the long term.