Messages in this thread Patch in this message | | | Date | Mon, 21 Jul 2008 22:18:19 +0300 | From | Eran Liberty <> | Subject | [PATCH 2.6.26] PCI: refuse to re-add a device to a bus upon pci_scan_child_bus() |
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Dear Penguins,
As a follow up on my own post ( http://lkml.org/lkml/2008/6/18/195 ), I have solved a small bug/misbehavior within the pci_scan_single_device().
The misbehavior manifest itself upon calling pci_scan_child_bus() with a bus which already contain some devices. After scanning is done devices that already existed will be present twice in the PCI bus devise list. Once with is_added indication and once without. Trying to add this bus will cause a resource conflict as the same device is already present and initialized.
This patch will simply prevent a device to be added to a pci bus list if it is already there.
Points to consider: 1. I am not a PCI Guru and might have over looked the bigger picture. Is it OK to prevent a device of being re-added? 2. I have decided that two devices are, in fact, the same instance if it has the same: vendor, device, and devfn. Is there a finer test for a device identity?
p.s. As per http://www.kernel.org/pub/linux/docs/lkml/#s1-10 it is preferred for Mozilla Firefox clients to attach the patch, hence my patch is attached.
Liberty
Signed-off-by: Eran Liberty <liberty@extricom.org> ---
drivers/pci/probe.c | 10 ++++++++++ 1 files changed, 10 insertions(+), 0 deletions(-)
diff --git a/drivers/pci/probe.c b/drivers/pci/probe.c index b1724cf..e3c3ee0 100644 --- a/drivers/pci/probe.c +++ b/drivers/pci/probe.c @@ -1002,11 +1002,21 @@ void pci_device_add(struct pci_dev *dev, struct pci_bus *bus) struct pci_dev *__ref pci_scan_single_device(struct pci_bus *bus, int devfn) { struct pci_dev *dev; + struct list_head *ln; dev = pci_scan_device(bus, devfn); if (!dev) return NULL; + /* refuse to re-add a device */ + list_for_each(ln, &bus->devices) { + struct pci_dev *d = pci_dev_b(ln); + if ((d->vendor == dev->vendor) && + (d->device == dev->device) && + (d->devfn == dev->devfn)) + return NULL; + } + pci_device_add(dev, bus); return dev; | |