On Mon, 2012-01-23 at 11:34 -0800, Linus Torvalds wrote: > On Mon, Jan 23, 2012 at 10:45 AM, Linus Torvalds > <torvalds@xxxxxxxxxxxxxxxxxxxx> wrote: > > > > Why isn't this magically true in this case? If some *other* random > > entry than the one that is being iterated over can magically be > > removed, then the whole thing is just pure and utter crap, and no > > amount of list maintenance can ever fix it. > > > > So explain. > > Ahh. I finally understand what's going on. The virtual device attached > to a physical device can go away, and it's on the same damn list. > > That's broken. Virtual devices set up by a physical device should be > *children* of the physical device, not "siblings". But that's > apparently not what the broken virtual PCI layer does. Thank the PCI SIG for that ... they are sibling functions (or even devices in some case) of the PF :-( > So I think that there are two possible solutions: > > (a) fix the virtual devices that are attached to physical devices to > really be children of the physical device, with the physical device as > a "bridge" to that virtual bus. This will confuse various other aspects of the PCI code since they are really siblings from an addressing standpoint (ie bus/dev/fn) Cheers, Ben. > I think this is the correct solution from any sane standpoint (now the > topology of the device tree actually matches the logical > relationship), which is why I think this is the RightThing(tm) to do. > And it should automatically fix this insane issue where removing a > device from a bus can remove *multiple* devices from the same list. > > (b) if that isn't an option, and the virtual devices make a mess, at > least don't make the code uglier, just do something like: > > while (!list_empty(&bus->devices)) { > struct pci_dev *dev = list_first_entry(struct pci_dev, bus_list); > > pci_stop_bus_device(dev); > } > > which at least isn't butt ugly. Add a large comment about how > pci_stop_bus_device() can remove multiple devices due to the virtual > devices having been done badly. > > Who is in charge of the whole 'is_virtfn' mess? How realistic is it to > fix that crud? > > Linus > -- > To unsubscribe from this list: send the line "unsubscribe linux-pci" in > the body of a message to majordomo@xxxxxxxxxxxxxxx > More majordomo info at http://vger.kernel.org/majordomo-info.html -- To unsubscribe from this list: send the line "unsubscribe linux-pci" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html