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    SubjectRe: [PATCH] pci: Fixing drivers/pci/search.c compilation warning.
    Matthew Wilcox wrote:
    > On Mon, Oct 27, 2008 at 11:18:43AM +0800, Zhao, Yu wrote:
    >> Matthew Wilcox wrote:
    >>> Yes, that's why pci_find_device() is deprecated. But it doesn't also
    >>> need to be buggy ;-)
    >> How about pci_get_bus_and_slot()? People would meet the problem with it
    >> anyway.
    >
    > What problem with it? It's documented to return the device with an
    > increased refcount, and the implementation appears to do exactly that:
    >
    > struct pci_dev * pci_get_bus_and_slot(unsigned int bus, unsigned int devfn)
    > {
    > struct pci_dev *dev = NULL;
    >
    > while ((dev = pci_get_device(PCI_ANY_ID, PCI_ANY_ID, dev)) != NULL) {
    > if (pci_domain_nr(dev->bus) == 0 &&
    > (dev->bus->number == bus && dev->devfn == devfn))
    > return dev;
    > }
    > return NULL;
    > }
    >
    > Are you saying some users of it neglect to decrement the refcount before
    > disposing of the device?
    >

    The 'dev' returned by pci_get_device() may be destroyed by PCI hotplug.
    I suppose that passing this 'dev' to pci_get_device() in the next loop
    would crash the system, right?


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