iommu: Remove __iommu_group_for_each_dev()

The last two users of it are quite trivial, just open code the one line
loop.
Reviewed-by: Lu Baolu <baolu.lu@linux.intel.com>
Tested-by: Heiko Stuebner <heiko@sntech.de>
Tested-by: Niklas Schnelle <schnelle@linux.ibm.com>
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>
Link: https://lore.kernel.org/r/16-v5-1b99ae392328+44574-iommu_err_unwind_jgg@nvidia.comSigned-off-by: Joerg Roedel <jroedel@suse.de>

drivers/iommu/iommu.c

@@ -1110,20 +1110,6 @@ void iommu_group_remove_device(struct device *dev)
 }
 EXPORT_SYMBOL_GPL(iommu_group_remove_device);
 
-static int __iommu_group_for_each_dev(struct iommu_group *group, void *data,
-				      int (*fn)(struct device *, void *))
-{
-	struct group_device *device;
-	int ret = 0;
-
-	for_each_group_device(group, device) {
-		ret = fn(device->dev, data);
-		if (ret)
-			break;
-	}
-	return ret;
-}
-
 /**
  * iommu_group_for_each_dev - iterate over each device in the group
  * @group: the group
@@ -1138,10 +1124,15 @@ static int __iommu_group_for_each_dev(struct iommu_group *group, void *data,
 int iommu_group_for_each_dev(struct iommu_group *group, void *data,
 			     int (*fn)(struct device *, void *))
 {
-	int ret;
+	struct group_device *device;
+	int ret = 0;
 
 	mutex_lock(&group->mutex);
-	ret = __iommu_group_for_each_dev(group, data, fn);
+	for_each_group_device(group, device) {
+		ret = fn(device->dev, data);
+		if (ret)
+			break;
+	}
 	mutex_unlock(&group->mutex);
 
 	return ret;
@@ -1791,20 +1782,12 @@ static int iommu_get_default_domain_type(struct iommu_group *group,
 	return best_type;
 }
 
-static int iommu_group_do_probe_finalize(struct device *dev, void *data)
+static void iommu_group_do_probe_finalize(struct device *dev)
 {
 	const struct iommu_ops *ops = dev_iommu_ops(dev);
 
 	if (ops->probe_finalize)
 		ops->probe_finalize(dev);
-
-	return 0;
-}
-
-static void __iommu_group_dma_finalize(struct iommu_group *group)
-{
-	__iommu_group_for_each_dev(group, group->default_domain,
-				   iommu_group_do_probe_finalize);
 }
 
 int bus_iommu_probe(const struct bus_type *bus)
@@ -1823,6 +1806,8 @@ int bus_iommu_probe(const struct bus_type *bus)
 		return ret;
 
 	list_for_each_entry_safe(group, next, &group_list, entry) {
+		struct group_device *gdev;
+
 		mutex_lock(&group->mutex);
 
 		/* Remove item from the list */
@@ -1834,7 +1819,15 @@ int bus_iommu_probe(const struct bus_type *bus)
 			return ret;
 		}
 		mutex_unlock(&group->mutex);
-		__iommu_group_dma_finalize(group);
+
+		/*
+		 * FIXME: Mis-locked because the ops->probe_finalize() call-back
+		 * of some IOMMU drivers calls arm_iommu_attach_device() which
+		 * in-turn might call back into IOMMU core code, where it tries
+		 * to take group->mutex, resulting in a deadlock.
+		 */
+		for_each_group_device(group, gdev)
+			iommu_group_do_probe_finalize(gdev->dev);
 	}
 
 	return 0;
@@ -2995,8 +2988,12 @@ static ssize_t iommu_group_store_type(struct iommu_group *group,
 	mutex_unlock(&group->mutex);
 
 	/* Make sure dma_ops is appropriatley set */
-	if (!ret)
-		__iommu_group_dma_finalize(group);
+	if (!ret) {
+		struct group_device *gdev;
+
+		for_each_group_device(group, gdev)
+			iommu_group_do_probe_finalize(gdev->dev);
+	}
 
 	return ret ?: count;
 }