Messages in this thread | | | Date | Wed, 11 Mar 2015 17:28:35 -0500 | From | Bjorn Helgaas <> | Subject | Re: [PATCH v6 03/30] PCI: Export busn_resource to drivers/pci |
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On Mon, Mar 09, 2015 at 10:34:00AM +0800, Yijing Wang wrote: > Export out busn_resource. Xen pcifront module need it. > > Signed-off-by: Yijing Wang <wangyijing@huawei.com> > --- > drivers/pci/pci.h | 2 ++ > drivers/pci/probe.c | 3 ++- > 2 files changed, 4 insertions(+), 1 deletions(-) > > diff --git a/drivers/pci/pci.h b/drivers/pci/pci.h > index 4091f82..eeacab9 100644 > --- a/drivers/pci/pci.h > +++ b/drivers/pci/pci.h > @@ -10,6 +10,8 @@ bool pcie_cap_has_lnkctl(const struct pci_dev *dev); > > /* Functions internal to the PCI core code */ > > +extern struct resource busn_resource; > + > int pci_create_sysfs_dev_files(struct pci_dev *pdev); > void pci_remove_sysfs_dev_files(struct pci_dev *pdev); > #if !defined(CONFIG_DMI) && !defined(CONFIG_ACPI) > diff --git a/drivers/pci/probe.c b/drivers/pci/probe.c > index 8ef0375..b97ea81 100644 > --- a/drivers/pci/probe.c > +++ b/drivers/pci/probe.c > @@ -17,12 +17,13 @@ > #define CARDBUS_LATENCY_TIMER 176 /* secondary latency timer */ > #define CARDBUS_RESERVE_BUSNR 3 > > -static struct resource busn_resource = { > +struct resource busn_resource = { > .name = "PCI busn", > .start = 0, > .end = 255, > .flags = IORESOURCE_BUS, > }; > +EXPORT_SYMBOL(busn_resource);
I don't think this is a good idea. We support multiple PCI domains, and each domain has its own 0-255 bus number range. This busn_resource is only for domain 0 and probably should be handled in arch code instead of the PCI core.
Right now, I think it's possible to call pci_scan_bus_parented() or pci_scan_bus() several times for buses in different domains, and they would all share the same busn_resource, which would cause corruption.
So it's already broken, but I don't want to make it harder to fix by exporting this stuff.
> > /* Ugh. Need to stop exporting this to modules. */ > LIST_HEAD(pci_root_buses); > -- > 1.7.1 >
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