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
