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    SubjectRe: [PATCH 1/2] pci: Block config access during BIST
    Greg KH wrote:
    > On Fri, Nov 19, 2004 at 02:23:22PM -0600, brking@us.ibm.com wrote:
    >
    >>-static inline int pci_read_config_byte(struct pci_dev *dev, int where, u8 *val)
    >>-{
    >>- return pci_bus_read_config_byte (dev->bus, dev->devfn, where, val);
    >>-}
    >
    >
    > Well, as much as I despise this patch, you should at least get it
    > correct :)
    >
    > You need to block the pci_bus_* functions too, otherwise the parts of
    > the kernel that use them will stomp all over your device, right?

    I thought about that when writing up this patch, but decided against it.
    I figured it was overkill and was going to make the patch more complicated
    than it needed to be to solve the main problem I have seen, which is
    userspace code, usually hotplug/coldplug scripts, reading config space
    when an adapter is running BIST.

    If you think there are usages of the pci_bus_* functions in the
    kernel after the adapter device driver gets loaded, from callers other
    than adapter device drivers and userspace APIs, I would have to agree
    with you. I was hoping to keep this patch as simple as possible.

    Having to protect the pci_bus_* functions requires a lookup in these
    functions to find the pci_dev to get the saved_config_space, which
    I was hoping to avoid.

    Ben - do you have any concerns with this limitation for the use you have
    for this set of APIs?



    --
    Brian King
    eServer Storage I/O
    IBM Linux Technology Center

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