On 08/03/18 16:17, Jonathan Cameron wrote: >> + arm_smmu_enable_ats(master); > It's a bit nasty not to handle the errors that this could output (other than > the ENOSYS for when it's not available). Seems that it would be nice to at > least add a note to the log if people are expecting it to work and it won't > because some condition or other isn't met.
I agree it's not ideal. Last time this came up the problem was that checking if ATS is supported requires an ugly ifdef. A proper implementation requires more support in the PCI core, e.g. a pci_ats_supported() function. https://www.spinics.net/lists/kvm/msg145932.html >> + >> group = iommu_group_get_for_dev(dev); >> - if (!IS_ERR(group)) { >> - arm_smmu_insert_master(smmu, master); >> - iommu_group_put(group); >> - iommu_device_link(&smmu->iommu, dev); >> + if (IS_ERR(group)) { >> + ret = PTR_ERR(group); >> + goto err_disable_ats; >> } >> >> - return PTR_ERR_OR_ZERO(group); >> + iommu_group_put(group); >> + arm_smmu_insert_master(smmu, master); >> + iommu_device_link(&smmu->iommu, dev); >> + >> + return 0; >> + >> +err_disable_ats: >> + arm_smmu_disable_ats(master); > master is leaked here I think... > Possibly other things as this doesn't line up with the > remove which I'd have mostly expected it to do. > There are some slightly fishy bits of ordering in the original code > anyway that I'm not seeing justification for (why is > the iommu_device_unlink later than one might expect for > example). Yeah, knowing the rest of the probing code, there may exist subtle legacy reasons for not freeing the master here and the strange orderings. I try to keep existing behaviors where possible since I barely even have the bandwidth to fix my own code. Thanks, Jean _______________________________________________ iommu mailing list iommu@lists.linux-foundation.org https://lists.linuxfoundation.org/mailman/listinfo/iommu
