> -----Original Message----- > From: Markus Armbruster [mailto:arm...@redhat.com] > Sent: Thursday, November 06, 2014 6:21 PM > To: SeokYeon Hwang > Cc: 'Paolo Bonzini'; 'Michael S. Tsirkin'; qemu-devel@nongnu.org > Subject: Re: [Qemu-devel] [PATCH] pci: fixed mismatch of error-handling > between pci_qdev_init() and qdev > > SeokYeon Hwang <syeon.hw...@samsung.com> writes: > > >> -----Original Message----- > >> From: Paolo Bonzini [mailto:paolo.bonz...@gmail.com] On Behalf Of > >> Paolo Bonzini > >> Sent: Wednesday, November 05, 2014 11:55 PM > >> To: Michael S. Tsirkin > >> Cc: Markus Armbruster; SeokYeon Hwang; qemu-devel@nongnu.org > >> Subject: Re: [Qemu-devel] [PATCH] pci: fixed mismatch of > >> error-handling between pci_qdev_init() and qdev > >> > >> > >> > >> On 05/11/2014 14:28, Michael S. Tsirkin wrote: > >> > > I think bypassing the question by converting to realize makes the > >> > > most sense... > >> > > >> > I'm fine with doing that but Markus's patches wouldn't yet have > >> > solved the problem by themselves since init is still around, right? > >> > > >> > This probably means fixing this bug can't justify merging the > >> > realize patchset after freeze. > >> > >> Yes, I agree. I meant that the API is not very well defined. I > >> would handle everything else on a case-by-case basis, by reviewing > >> each init function that is converted to realize. > >> > >> Since the patch was for an out-of-tree device, it can wait for 2.3 > anyway. > >> > >> Paolo > > > > I cannot fully understand your conversation. > > You appear to have a PCIDeviceClass method init() returning a positive > value. Doesn't work. Only values <= 0 do. > > Your proposed fix is to make its caller treat a positive value like a > negative one. > > Paolo points out that init()'s contract is unclear. His preferred way of > clarifying it is to convert PCI from init() to realize(), which has a > sufficiently clear contract. > > Doesn't help you now. My "pci: Partial conversion to realize" series, > will help you once it lands, but only if you convert your device. > > You obviously want a solution earlier. The one you proposed implicitly > clarifies the PCIDeviceClass init() contract to "zero means success, > anything else failure". I don't think that's a good idea, because it > makes PCIDeviceClass's init() differ from DeviceClass's. There, non- > negative value means success, negative means failure (see > device_realize()). > > Fix your device not to return positive values instead. > > You could additionally fix pci_qdev_init() to treat positive numbers as > success, for consistency with device_realize(), but that requires auditing > all existing PCIDeviceClass init() methods. Waste of your time, because > they all go away when we convert to realize(). > > > But, I think this patch is still worth before all 'init()' convert to > > 'realize()'. > > Moreover, It has no side effect at all. > > I don't like it, because it makes PCIDeviceClass's init() inconsistent > with DeviceClass's.
I understand completely. Thank you for your kind explanation.
