Messages in this thread | | | Date | Thu, 17 Dec 2015 17:57:43 +0000 | From | Keith Busch <> | Subject | Re: [PATCHv6 2/7] pci: child bus alloc fix on constrained resource |
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On Thu, Dec 17, 2015 at 11:27:18AM -0600, Bjorn Helgaas wrote: > On Mon, Dec 07, 2015 at 02:32:24PM -0700, Keith Busch wrote: > > + if (busnr > parent->busn_res.end) { > > + dev_printk(KERN_DEBUG, &parent->dev, > > + "can not alloc bus:%d under %pR\n", busnr, > > + &parent->busn_res); > > + return NULL; > > Can you take a look at 1820ffdccb9b ("PCI: Make sure bus number resources > stay within their parents bounds") and 12d8706963f0 ("Revert "PCI: Make > sure bus number resources stay within their parents bounds"")? > > This is implemented differently, but it seems like it might expose the same > problem we found with 1820ffdccb9b. > > If you could take a look and confirm that "no, this does something > differently than 1820ffdccb9b did" or "yes, this might expose that problem > again," that would help.
Thank you for the references. I think 1820ffdccb9b had the check too late, creating the child bus with resource conflicts. That'd probably make it appear unavailable. But I believe this new proposal will still break the same setup for a different reason.
We can live with this issue for now if we want to drop this patch from the series. The only way we encounter a problem is when the config space aperture is artificially constrained, so I can request the feature be put on hold while a better fix is developed.
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