Re: [Qemu-devel] [PATCH v3 4/9] ide: Drop redundant IDEState member bs

[Markus Armbruster]

Stefano Stabellini <address@hidden> writes:

> On Thu, 6 Feb 2014, Markus Armbruster wrote:
>> Stefano Stabellini <address@hidden> writes:
>> 
>> > On Wed, 5 Feb 2014, Markus Armbruster wrote:
>> >> [Note cc: Stefano]
>> >> 
>> >> Kevin Wolf <address@hidden> writes:
>> >> 
>> >> > Am 30.01.2014 um 13:16 hat Markus Armbruster geschrieben:
>> >> >> It's a copy of dev->conf.bs.  The copy was needed for non-qdevified
>> >> >> controllers, which lacked dev.
>> >> >> 
>> >> >> Note how pci_piix3_xen_ide_unplug() cleared the copy.  We'll get back
>> >> >> to that in the next few commits.
>> >> >> 
>> >> >> Signed-off-by: Markus Armbruster <address@hidden>
>> >> >
>> >> > So this pci_piix3_xen_ide_unplug() is what happens here:
>> >> >
>> >> >> --- a/hw/ide/piix.c
>> >> >> +++ b/hw/ide/piix.c
>> >> >> @@ -169,12 +169,9 @@ static int pci_piix_ide_initfn(PCIDevice *dev)
>> >> >>  
>> >> >>  static int pci_piix3_xen_ide_unplug(DeviceState *dev)
>> >> >>  {
>> >> >> -    PCIIDEState *pci_ide;
>> >> >>      DriveInfo *di;
>> >> >>      int i = 0;
>> >> >>  
>> >> >> -    pci_ide = PCI_IDE(dev);
>> >> >> -
>> >> >>      for (; i < 3; i++) {
>> >> >>          di = drive_get_by_index(IF_IDE, i);
>> >> >>          if (di != NULL && !di->media_cd) {
>> >> >> @@ -183,7 +180,6 @@ static int pci_piix3_xen_ide_unplug(DeviceState 
>> >> >> *dev)
>> >> >>                  bdrv_detach_dev(di->bdrv, ds);
>> >> >>              }
>> >> >>              bdrv_close(di->bdrv);
>> >> >> -            pci_ide->bus[di->bus].ifs[di->unit].bs = NULL;
>> >> >>              drive_put_ref(di);
>> >> >>          }
>> >> >>      }
>> >> >
>> >> > Probably I'm just missing the obvious, but it seems to me that the
>> >> > copy was cleared here, while the original was left around. This was
>> >> > no problem because the original was unused anyway after device
>> >> > initialisation.
>> >> >
>> >> > Now that the copy doesn't exist any more, we can't clear it, obviously,
>> >> > but why don't we have to clear the original? Won't we still run the
>> >> > "device is attached" code branches even though the device is really
>> >> > unplugged?
>> >> 
>> >> It's been a while since I wrote this.  Almost 14 months, in fact.
>> >> 
>> >> No other IDE controller implements DeviceClass method unplug().  I can't
>> >> remember why the normal code to detach the backend (release_drive())
>> >> doesn't do here.  Stefano, can you help?
>> >
>> > Too long to be able to remember the exact details :-/
>> > However if you point me to a branch I can give it a try and tell you if
>> > the unplug still works as it used to.
>> 
>> Series trivially rebased to current master available at
>> git://repo.or.cz/qemu/armbru.git branch kill-non-qdev-ide
>
> Unfortunately it doesn't work: I can see both sda and xvda being present
> after the system has booted.

Thank you for testing.  I'll try to clear the originals like Kevin
suggested.  Hopefully, that'll pass your test.