Messages in this thread | | | Date | Thu, 12 Mar 2015 19:42:25 +0800 | From | Yijing Wang <> | Subject | Re: [PATCH v6 03/30] PCI: Export busn_resource to drivers/pci |
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>> -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.
Hi Bjorn, busn_resource may would not be shared by multi domains,
We insert bus number resource like:
pci_add_resource(&resources, &busn_resource); pci_bus_insert_busn_res(root_bus, start, bus_max); //start is the root bus number provided by arch pci host driver, bus max here == 255 get_pci_domain_busn_res(domain) //for root bus //try to get a domain specific pci_domain_busn_res, if not exist, create it. request_resource_conflict(domain_specific_busn_res, res) //request busn res(start, bus_max) from the pci_domain_busn_res.
So every domain has its own pci_domain_busn_res , different domain would not share the same bus number resource.
Do I understand correct ?
Thanks! Yijing.
> >> >> /* Ugh. Need to stop exporting this to modules. */ >> LIST_HEAD(pci_root_buses); >> -- >> 1.7.1 >> > > . >
-- Thanks! Yijing
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