Messages in this thread | | | Date | Mon, 27 Oct 2008 11:18:43 +0800 | From | "Zhao, Yu" <> | Subject | Re: [PATCH] pci: Fixing drivers/pci/search.c compilation warning. |
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Matthew Wilcox wrote: > On Sun, Oct 26, 2008 at 08:51:25PM +0800, Yu Zhao wrote: >> This reminds me of other problems of PCI search functions. >> >> The 'dev_start' is passed to bus_find_device(), and its 'knode_bus' >> reference count is decreased by klist_iter_init_node() in that function. >> The problem is the reference count may be already decrease to 0 because >> the PCI device 'from' is hot-plugged off (e.g., pci_remove_bus) when the >> search goes. A warning is fired when klist_iter_init_node() detects the >> reference count becomes 0. >> >> Some code uses pci_find_device() in a way that is not safe with the >> hotplug, because a device may be destroyed after bus_find_device() >> returns it and before it's held by pci_dev_get() in the next round. >> Following is an example from a random grep: > > 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.
Thanks, Yu
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