On Thursday, January 02, 2014 02:47:04 PM Yinghai Lu wrote: > On Tue, Dec 31, 2013 at 1:03 PM, Rafael J. Wysocki <rjw@xxxxxxxxxxxxx> wrote: > > On Tuesday, December 31, 2013 10:45:46 AM Yinghai Lu wrote: > >> On Mon, Dec 30, 2013 at 5:15 AM, Rafael J. Wysocki <rjw@xxxxxxxxxxxxx> wrote: > >> > On Monday, December 30, 2013 01:51:28 PM Rafael J. Wysocki wrote: > >> >> > We have patches that need to stop ioapic and iommu between > >> >> > pci_stop_root_bus and pci_remove_root_bus. > >> > > >> > BTW, what *exactly* do they need to be stopped between? After these two patches: > >> > >> need to stop regular pci drivers before stop "driver" for ioapic/dmar. > >> > >> > > >> >> > Please check if the problem still happen after > >> >> > > >> >> > http://git.kernel.org/cgit/linux/kernel/git/helgaas/pci.git/patch/?id=c4a0a5d964e90b93eb4101c3927b788e083e530f > >> >> > > >> >> > http://git.kernel.org/cgit/linux/kernel/git/helgaas/pci.git/patch/?id=e3b439e1d315aff59c1b4f0fc43c5cd2d82b4138 > >> > > >> > pci_stop_root_bus() is just a walk over devices on the root bus stopping > >> > them and pci_remove_root_bus() starts with the removal of those devices. > >> > > >> > Surely, those two list walks can be combined into one? > >> > >> maybe ok, but we have to problem to make sure stop pci drivers before > >> "driver" for ioapic/dmar. > > > > That's fine, but ioapic/dmar stopping need not happen between the stopping of > > drivers and removing of devices on the root bus I suppose? > > > > Actually, I think that the ioapic/dmar stopping should be carried out after > > removing all of the root bus devices, or it can be racy with respect to a > > driver reload. Isn't that the case? > > No. It should be before removing all root bus devices. > as they need to access the pci devices during stop ioapic and dmar. > > Also ioapic itself could one one pci device. Well, if we stop drivers first, then stop ioapic/dmar and *then* remove devices, it is possible to rebind a driver to a device after ioapic/dmar has been stopped, which I guess will not lead to anything nice? Rafael -- 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
