Will Deacon
2022-Nov-08 13:20 UTC
[PATCH v7 4/5] iommu: Use EINVAL for incompatible device/domain in ->attach_dev
On Mon, Nov 07, 2022 at 04:14:32PM -0800, Nicolin Chen wrote:> On Mon, Nov 07, 2022 at 03:26:45PM +0000, Will Deacon wrote: > > > > diff --git a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c > > > index ba47c73f5b8c..01fd7df16cb9 100644 > > > --- a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c > > > +++ b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c > > > @@ -2430,23 +2430,14 @@ static int arm_smmu_attach_dev(struct iommu_domain *domain, struct device *dev) > > > goto out_unlock; > > > } > > > } else if (smmu_domain->smmu != smmu) { > > > - dev_err(dev, > > > - "cannot attach to SMMU %s (upstream of %s)\n", > > > - dev_name(smmu_domain->smmu->dev), > > > - dev_name(smmu->dev)); > > > - ret = -ENXIO; > > > + ret = -EINVAL; > > > goto out_unlock; > > > } else if (smmu_domain->stage == ARM_SMMU_DOMAIN_S1 && > > > master->ssid_bits != smmu_domain->s1_cfg.s1cdmax) { > > > - dev_err(dev, > > > - "cannot attach to incompatible domain (%u SSID bits != %u)\n", > > > - smmu_domain->s1_cfg.s1cdmax, master->ssid_bits); > > > ret = -EINVAL; > > > goto out_unlock; > > > } else if (smmu_domain->stage == ARM_SMMU_DOMAIN_S1 && > > > smmu_domain->stall_enabled != master->stall_enabled) { > > > - dev_err(dev, "cannot attach to stall-%s domain\n", > > > - smmu_domain->stall_enabled ? "enabled" : "disabled"); > > > ret = -EINVAL; > > > goto out_unlock; > > > } > > > I think it would be helpful to preserve these messages using > > dev_err_ratelimited() so that attach failure can be diagnosed without > > having to hack the messages back into the driver. > > Thank you for the review. > > The change is already picked up last week. Yet, I can add prints > back with a followup patch, if no one has a problem with that.Sorry, I fell behind with upstream so I got to this late. A patch on top would be fantastic!> Also, I am not quite sure what the use case would be to have an > error print. Perhaps dev_dbg() would be more fitting if it is > just for diagnosis?Sure, that works for me. I think the messages are useful for folks triggering this path e.g. via sysfs but if they're limited to debug I think that's better than removing them altogether. Cheers, Will