Markus Armbruster <arm...@redhat.com> writes: > Cao jin <caoj.f...@cn.fujitsu.com> writes: > >> Hi John >> >> On 12/05/2015 01:55 AM, John Snow wrote: >>> >>> >>> On 12/04/2015 02:47 AM, Cao jin wrote: >>>> Hi, >>>> As you know, there are many PCI devices still using .init() as its >>>> initialization function, I am planning to do the "convert to >>>> realize()" >>>> work, and PCI bridge devices are chosen first. >>>> The supporting functions should be modified first. msi_init() a >>>> supporting >>>> function for PCI devices. >>>> >>>> Maybe it should be put in 2.6, as title indicated >>>> >>>> Cao jin (2): >>>> Add param Error** to msi_init() >>>> Modify callers of msi_init() >>>> >>>> hw/audio/intel-hda.c | 7 ++++++- >>>> hw/ide/ich.c | 2 +- >>>> hw/net/vmxnet3.c | 3 ++- >>>> hw/pci-bridge/ioh3420.c | 6 +++++- >>>> hw/pci-bridge/pci_bridge_dev.c | 6 +++++- >>>> hw/pci-bridge/xio3130_downstream.c | 7 ++++++- >>>> hw/pci-bridge/xio3130_upstream.c | 7 ++++++- >>>> hw/pci/msi.c | 17 +++++++++++++---- >>>> hw/scsi/megasas.c | 2 +- >>>> hw/scsi/vmw_pvscsi.c | 3 ++- >>>> hw/usb/hcd-xhci.c | 5 ++++- >>>> hw/vfio/pci.c | 3 ++- >>>> include/hw/pci/msi.h | 4 ++-- >>>> 13 files changed, 55 insertions(+), 17 deletions(-) >>>> >>> >>> You'll need to squash these patches as the first patch will break git >>> bisect. >>> >> >> Ok, will squash it. And I have another question： what`s the benefit >> of converting to realize? Because AFAICT, doing this make the error >> reporting machanism seems clean & clear, all device-init errors are >> passed above along the call chain. I mean, besides, are there any >> other benefits? > > Let's compare behavior on error: > > * realize methods pass an error object to their caller > > The caller decides how to handle the error. > > Many callers simply pass it on. Typically, errors from realize are > passed up the call chain through qdev_device_add(). > > Eventually, the caller that handles the error is reached. If the > error needs to be reported to the user, it decides how. Examples: > > - device_init_func(), which does the actual work for -device, reports > the human-readable message to stderr. > > - hmp_device_add(), which does the work for HMP device_add, reports > the human-readable message to to the appropriate monitor. > > - handle_qmp_command(), which handles all QMP commands including QMP > device_add, sends a QMP error reply down the QMP connection. > > - petalogix_ml605_init(), which creates the "petalogix-ml605" board, > aborts when realizing the CPU fails. > > * init methods report to stderr and return -1 > > Fine when the error should be reported to stderr.
Correction: init methods should use error_report(), which reports either to stderr or the current monitor. > This is fine for > some of the above examples, and wrong on others. In particular, a > device needs to provide a realize method to be fully work with > device_add, unless its init method cannot fail. This is the case all the same.
