On 2021-05-11 10:05 a.m., Don Dutile wrote: > ... add a flag (set for p2pdma use) to the function to print out what the > root->devfn is, and what > the device is so the needed quirk &/or modification can added to handle when > this assumption fails; > or make it a prdebug that can be flipped on for this failing situation, > again, to add needed change to accomodate.
Good idea! Will add. >> root = NULL; >> out: >> pci_dev_get(root); >> return root; >> } >> EXPORT_SYMBOL(pci_get_root_slot); >> >> ...I think that's a lot clearer to the reader, about what's going on here. >> >> Note that I'm not really sure if it *is* safe, I would need to ask other >> PCIe subsystem developers with more experience. But I don't think anyone >> is trying to make p2pdma calls so early that PCIe buses are uninitialized. >> >> >>> + >>> + if (!root || root->devfn) >>> return false; >>> vendor = root->vendor; >>> device = root->device; >>> - pci_dev_put(root); > and the reason to remove the dev_put is b/c it can sleep as well? > is that ok, given the dev_get that John put into the new pci_get_root_slot()? > ... seems like a locking version with no get/put's is needed, or, fix the > host-bridge setups so no !NULL self pointers. The dev_get is redundant here seeing we hold references to child devices. It was only in the previous code because we were using pci_get_slot() to get the device which did the get for us. Logan _______________________________________________ iommu mailing list iommu@lists.linux-foundation.org https://lists.linuxfoundation.org/mailman/listinfo/iommu
