Messages in this thread | | | Date | Mon, 27 Oct 2008 15:13:51 +0800 | From | "Zhao, Yu" <> | Subject | Re: [PATCH] pci: Fixing drivers/pci/search.c compilation warning. |
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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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