iommu: Resolve ops in iommu_init_device()

Since iommu_init_device() was factored out, it is in fact the only
consumer of the ops which __iommu_probe_device() is resolving, so let it
do that itself rather than passing them in. This also puts the ops
lookup at a more logical point relative to the rest of the flow through
__iommu_probe_device().

Signed-off-by: Robin Murphy <[e-mail]>
Reviewed-by: Jason Gunthorpe <[e-mail]>
Link: https://lore.kernel.org/r/fa4b[e-mail]
Signed-off-by: Joerg Roedel <[e-mail]>

drivers/iommu/iommu.c

···
  * Init the dev->iommu and dev->iommu_group in the struct device and get the
  * driver probed
  */
-static int iommu_init_device(struct device *dev, const struct iommu_ops *ops)
+static int iommu_init_device(struct device *dev)
 {
+	const struct iommu_ops *ops;
 	struct iommu_device *iommu_dev;
 	struct iommu_group *group;
 	int ret;
 
 	if (!dev_iommu_get(dev))
 		return -ENOMEM;
+	/*
+	 * For FDT-based systems and ACPI IORT/VIOT, drivers register IOMMU
+	 * instances with non-NULL fwnodes, and client devices should have been
+	 * identified with a fwspec by this point. Otherwise, we can currently
+	 * assume that only one of Intel, AMD, s390, PAMU or legacy SMMUv2 can
+	 * be present, and that any of their registered instances has suitable
+	 * ops for probing, and thus cheekily co-opt the same mechanism.
+	 */
+	ops = iommu_fwspec_ops(dev->iommu->fwspec);
+	if (!ops) {
+		ret = -ENODEV;
+		goto err_free;
+	}
 
 	if (!try_module_get(ops->owner)) {
 		ret = -EINVAL;
···
 
 static int __iommu_probe_device(struct device *dev, struct list_head *group_list)
 {
-	const struct iommu_ops *ops;
 	struct iommu_group *group;
 	struct group_device *gdev;
 	int ret;
 
-	/*
-	 * For FDT-based systems and ACPI IORT/VIOT, drivers register IOMMU
-	 * instances with non-NULL fwnodes, and client devices should have been
-	 * identified with a fwspec by this point. Otherwise, we can currently
-	 * assume that only one of Intel, AMD, s390, PAMU or legacy SMMUv2 can
-	 * be present, and that any of their registered instances has suitable
-	 * ops for probing, and thus cheekily co-opt the same mechanism.
-	 */
-	ops = iommu_fwspec_ops(dev_iommu_fwspec_get(dev));
-	if (!ops)
-		return -ENODEV;
 	/*
 	 * Serialise to avoid races between IOMMU drivers registering in
 	 * parallel and/or the "replay" calls from ACPI/OF code via client
···
 	if (dev->iommu_group)
 		return 0;
 
-	ret = iommu_init_device(dev, ops);
+	ret = iommu_init_device(dev);
 	if (ret)
 		return ret;