Re: [PATCH 2.6.24-rc4] PCI: refuse to re-add a device to a bus uponpci_scan_child_bus()

From: Eran Liberty
Date: Sun Jul 20 2008 - 12:51:44 EST


The subject is wrong! it is 2.6.26-rc4.

I will re-email with a corrected subject for automated scripts sake.

Liberty

Eran Liberty wrote:
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 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@xxxxxxxxxxxxx>
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