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    SubjectRe: [PATCH v8 06/22] PCI: split registration of PCI bus devices into two stages
    Date
    On Friday, January 11, 2013 02:40:33 PM Yinghai Lu wrote:
    > From: Jiang Liu <jiang.liu@huawei.com>
    >
    > When handling BUS_NOTIFY_ADD_DEVICE event for a PCI bridge device,
    > the notification handler can't hold reference count to the new PCI bus
    > because the device object for the new bus (pci_dev->subordinate->dev)
    > hasn't been initialized yet.

    It doesn't look like BUS_NOTIFY_ADD_DEVICE is used by the PCI bus type
    in the mainline.

    Is it in linux-next?

    If not, then I don't see why we need this patch.

    Thanks,
    Rafael


    > Split the registration of PCI bus device into two stages as below,
    > so that the event handler could hold reference count to the new PCI bus
    > when handling BUS_NOTIFY_ADD_DEVICE event.
    >
    > 1) device_initialize(&pci_dev->dev)
    > 2) device_initialize(&pci_dev->subordinate->dev)
    > 3) notify BUS_NOTIFY_ADD_DEVICE event for pci_dev
    > 4) device_add(&pci_dev->dev)
    > 5) device_add(&pci_dev->subordinate->dev)
    >
    > Signed-off-by: Jiang Liu <jiang.liu@huawei.com>
    > Signed-off-by: Yinghai Lu <yinghai@kernel.org>
    > ---
    > drivers/pci/bus.c | 2 +-
    > drivers/pci/probe.c | 4 +++-
    > drivers/pci/remove.c | 10 +++++-----
    > 3 files changed, 9 insertions(+), 7 deletions(-)
    >
    > diff --git a/drivers/pci/bus.c b/drivers/pci/bus.c
    > index 847f3ca..5f9c728 100644
    > --- a/drivers/pci/bus.c
    > +++ b/drivers/pci/bus.c
    > @@ -200,7 +200,7 @@ int pci_bus_add_child(struct pci_bus *bus)
    > if (bus->bridge)
    > bus->dev.parent = bus->bridge;
    >
    > - retval = device_register(&bus->dev);
    > + retval = device_add(&bus->dev);
    > if (retval)
    > return retval;
    >
    > diff --git a/drivers/pci/probe.c b/drivers/pci/probe.c
    > index 48b35e1..dc4fde3 100644
    > --- a/drivers/pci/probe.c
    > +++ b/drivers/pci/probe.c
    > @@ -642,6 +642,7 @@ static struct pci_bus *pci_alloc_child_bus(struct pci_bus *parent,
    > */
    > child->dev.class = &pcibus_class;
    > dev_set_name(&child->dev, "%04x:%02x", pci_domain_nr(child), busnr);
    > + device_initialize(&child->dev);
    >
    > /*
    > * Set up the primary, secondary and subordinate
    > @@ -1678,7 +1679,8 @@ struct pci_bus *pci_create_root_bus(struct device *parent, int bus,
    > b->dev.class = &pcibus_class;
    > b->dev.parent = b->bridge;
    > dev_set_name(&b->dev, "%04x:%02x", pci_domain_nr(b), bus);
    > - error = device_register(&b->dev);
    > + device_initialize(&b->dev);
    > + error = device_add(&b->dev);
    > if (error)
    > goto class_dev_reg_err;
    >
    > diff --git a/drivers/pci/remove.c b/drivers/pci/remove.c
    > index fc38c48..a1fdd0f 100644
    > --- a/drivers/pci/remove.c
    > +++ b/drivers/pci/remove.c
    > @@ -48,11 +48,11 @@ void pci_remove_bus(struct pci_bus *bus)
    > list_del(&bus->node);
    > pci_bus_release_busn_res(bus);
    > up_write(&pci_bus_sem);
    > - if (!bus->is_added)
    > - return;
    > -
    > - pci_remove_legacy_files(bus);
    > - device_unregister(&bus->dev);
    > + if (bus->is_added) {
    > + pci_remove_legacy_files(bus);
    > + device_del(&bus->dev);
    > + }
    > + put_device(&bus->dev);
    > }
    > EXPORT_SYMBOL(pci_remove_bus);
    >
    >
    --
    I speak only for myself.
    Rafael J. Wysocki, Intel Open Source Technology Center.


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