On 2021-06-18 08:41, Jean-Philippe Brucker wrote:
Hi Eric,
On Wed, Jun 16, 2021 at 11:35:13AM +0200, Eric Auger wrote:
-const struct iommu_ops *iort_iommu_configure_id(struct device *dev,
- const u32 *id_in)
+int iort_iommu_configure_id(struct device *dev, const u32 *id_in)
{
struct acpi_iort_node *node;
- const struct iommu_ops *ops;
+ const struct iommu_ops *ops = NULL;
Oops, I need to remove this (and add -Werror to my tests.)
+static const struct iommu_ops *acpi_iommu_configure_id(struct device *dev,
+ const u32 *id_in)
+{
+ int err;
+ const struct iommu_ops *ops;
+
+ /*
+ * If we already translated the fwspec there is nothing left to do,
+ * return the iommu_ops.
+ */
+ ops = acpi_iommu_fwspec_ops(dev);
+ if (ops)
+ return ops;
+
+ err = iort_iommu_configure_id(dev, id_in);
+
+ /*
+ * If we have reason to believe the IOMMU driver missed the initial
+ * add_device callback for dev, replay it to get things in order.
+ */
+ if (!err && dev->bus && !device_iommu_mapped(dev))
+ err = iommu_probe_device(dev);
Previously we had:
if (!err) {
ops = iort_fwspec_iommu_ops(dev);
err = iort_add_device_replay(dev);
}
Please can you explain the transform? I see the
acpi_iommu_fwspec_ops call below but is it not straightforward to me.
I figured that iort_add_device_replay() is only used once and is
sufficiently simple to be inlined manually (saving 10 lines). Then I
replaced the ops assignment with returns, which saves another line and may
be slightly clearer? I guess it's mostly a matter of taste, the behavior
should be exactly the same.
Right, IIRC the multiple assignments to ops were more of a haphazard
evolution inherited from the DT version, and looking at it now I think
the multiple-return is indeed a bit nicer.
Similarly, it looks like the factoring out of iort_add_device_replay()
was originally an attempt to encapsulate the IOMMU_API dependency, but
things have moved around a lot since then, so that seems like a sensible
simplification to make too.
Robin.
Also the comment mentions replay. Unsure if it is still OK.
The "replay" part is, but "add_device" isn't accurate because it has since
been replaced by probe_device. I'll refresh the comment.
Thanks,
Jean
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