iommu: remove the put_resv_regions method

All drivers that implement get_resv_regions just use
generic_put_resv_regions to implement the put side.  Remove the
indirections and document the allocations constraints.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Lu Baolu <baolu.lu@linux.intel.com>
Link: https://lore.kernel.org/r/20220708080616.238833-4-hch@lst.de
Signed-off-by: Joerg Roedel <jroedel@suse.de>

Author: Christoph Hellwig

drivers/iommu/amd/iommu.c

@@ -2280,7 +2280,6 @@ const struct iommu_ops amd_iommu_ops = {
 	.probe_finalize = amd_iommu_probe_finalize,
 	.device_group = amd_iommu_device_group,
 	.get_resv_regions = amd_iommu_get_resv_regions,
-	.put_resv_regions = generic_iommu_put_resv_regions,
 	.is_attach_deferred = amd_iommu_is_attach_deferred,
 	.pgsize_bitmap	= AMD_IOMMU_PGSIZES,
 	.def_domain_type = amd_iommu_def_domain_type,

drivers/iommu/apple-dart.c

@@ -768,7 +768,6 @@ static const struct iommu_ops apple_dart_iommu_ops = {
 	.of_xlate = apple_dart_of_xlate,
 	.def_domain_type = apple_dart_def_domain_type,
 	.get_resv_regions = apple_dart_get_resv_regions,
-	.put_resv_regions = generic_iommu_put_resv_regions,
 	.pgsize_bitmap = -1UL, /* Restricted during dart probe */
 	.owner = THIS_MODULE,
 	.default_domain_ops = &(const struct iommu_domain_ops) {

drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c

@@ -2852,7 +2852,6 @@ static struct iommu_ops arm_smmu_ops = {
 	.device_group		= arm_smmu_device_group,
 	.of_xlate		= arm_smmu_of_xlate,
 	.get_resv_regions	= arm_smmu_get_resv_regions,
-	.put_resv_regions	= generic_iommu_put_resv_regions,
 	.dev_enable_feat	= arm_smmu_dev_enable_feature,
 	.dev_disable_feat	= arm_smmu_dev_disable_feature,
 	.sva_bind		= arm_smmu_sva_bind,

drivers/iommu/arm/arm-smmu/arm-smmu.c

@@ -1584,7 +1584,6 @@ static struct iommu_ops arm_smmu_ops = {
 	.device_group		= arm_smmu_device_group,
 	.of_xlate		= arm_smmu_of_xlate,
 	.get_resv_regions	= arm_smmu_get_resv_regions,
-	.put_resv_regions	= generic_iommu_put_resv_regions,
 	.def_domain_type	= arm_smmu_def_domain_type,
 	.pgsize_bitmap		= -1UL, /* Restricted during device attach */
 	.owner			= THIS_MODULE,

drivers/iommu/intel/iommu.c

@@ -4911,7 +4911,6 @@ const struct iommu_ops intel_iommu_ops = {
 	.probe_finalize		= intel_iommu_probe_finalize,
 	.release_device		= intel_iommu_release_device,
 	.get_resv_regions	= intel_iommu_get_resv_regions,
-	.put_resv_regions	= generic_iommu_put_resv_regions,
 	.device_group		= intel_iommu_device_group,
 	.dev_enable_feat	= intel_iommu_dev_enable_feat,
 	.dev_disable_feat	= intel_iommu_dev_disable_feat,

drivers/iommu/iommu.c

@@ -2579,27 +2579,14 @@ void iommu_get_resv_regions(struct device *dev, struct list_head *list)
 		ops->get_resv_regions(dev, list);
 }
 
-void iommu_put_resv_regions(struct device *dev, struct list_head *list)
-{
-	const struct iommu_ops *ops = dev_iommu_ops(dev);
-
-	if (ops->put_resv_regions)
-		ops->put_resv_regions(dev, list);
-}
-
 /**
- * generic_iommu_put_resv_regions - Reserved region driver helper
+ * iommu_put_resv_regions - release resered regions
  * @dev: device for which to free reserved regions
  * @list: reserved region list for device
  *
- * IOMMU drivers can use this to implement their .put_resv_regions() callback
- * for simple reservations. If a per region callback is provided that will be
- * used to free all memory allocations associated with the reserved region or
- * else just free up the memory for the regions. If an IOMMU driver allocates
- * additional resources per region, it is going to have to implement a custom
- * callback.
+ * This releases a reserved region list acquired by iommu_get_resv_regions().
  */
-void generic_iommu_put_resv_regions(struct device *dev, struct list_head *list)
+void iommu_put_resv_regions(struct device *dev, struct list_head *list)
 {
 	struct iommu_resv_region *entry, *next;
 
@@ -2610,7 +2597,7 @@ void generic_iommu_put_resv_regions(struct device *dev, struct list_head *list)
 			kfree(entry);
 	}
 }
-EXPORT_SYMBOL(generic_iommu_put_resv_regions);
+EXPORT_SYMBOL(iommu_put_resv_regions);
 
 struct iommu_resv_region *iommu_alloc_resv_region(phys_addr_t start,
 						  size_t length, int prot,

drivers/iommu/mtk_iommu.c

@@ -928,7 +928,6 @@ static const struct iommu_ops mtk_iommu_ops = {
 	.device_group	= mtk_iommu_device_group,
 	.of_xlate	= mtk_iommu_of_xlate,
 	.get_resv_regions = mtk_iommu_get_resv_regions,
-	.put_resv_regions = generic_iommu_put_resv_regions,
 	.pgsize_bitmap	= SZ_4K | SZ_64K | SZ_1M | SZ_16M,
 	.owner		= THIS_MODULE,
 	.default_domain_ops = &(const struct iommu_domain_ops) {

drivers/iommu/virtio-iommu.c

@@ -964,7 +964,7 @@ static struct iommu_device *viommu_probe_device(struct device *dev)
 	return &viommu->iommu;
 
 err_free_dev:
-	generic_iommu_put_resv_regions(dev, &vdev->resv_regions);
+	iommu_put_resv_regions(dev, &vdev->resv_regions);
 	kfree(vdev);
 
 	return ERR_PTR(ret);
@@ -983,7 +983,7 @@ static void viommu_release_device(struct device *dev)
 {
 	struct viommu_endpoint *vdev = dev_iommu_priv_get(dev);
 
-	generic_iommu_put_resv_regions(dev, &vdev->resv_regions);
+	iommu_put_resv_regions(dev, &vdev->resv_regions);
 	kfree(vdev);
 }
 
@@ -1007,7 +1007,6 @@ static struct iommu_ops viommu_ops = {
 	.release_device		= viommu_release_device,
 	.device_group		= viommu_device_group,
 	.get_resv_regions	= viommu_get_resv_regions,
-	.put_resv_regions	= generic_iommu_put_resv_regions,
 	.of_xlate		= viommu_of_xlate,
 	.owner			= THIS_MODULE,
 	.default_domain_ops = &(const struct iommu_domain_ops) {

include/linux/iommu.h

@@ -209,7 +209,6 @@ struct iommu_iotlb_gather {
  *                  group and attached to the groups domain
  * @device_group: find iommu group for a particular device
  * @get_resv_regions: Request list of reserved regions for a device
- * @put_resv_regions: Free list of reserved regions for a device
  * @of_xlate: add OF master IDs to iommu grouping
  * @is_attach_deferred: Check if domain attach should be deferred from iommu
  *                      driver init to device driver init (default no)
@@ -240,7 +239,6 @@ struct iommu_ops {
 
 	/* Request/Free a list of reserved regions for a device */
 	void (*get_resv_regions)(struct device *dev, struct list_head *list);
-	void (*put_resv_regions)(struct device *dev, struct list_head *list);
 
 	int (*of_xlate)(struct device *dev, struct of_phandle_args *args);
 	bool (*is_attach_deferred)(struct device *dev);
@@ -454,8 +452,6 @@ extern void iommu_set_fault_handler(struct iommu_domain *domain,
 
 extern void iommu_get_resv_regions(struct device *dev, struct list_head *list);
 extern void iommu_put_resv_regions(struct device *dev, struct list_head *list);
-extern void generic_iommu_put_resv_regions(struct device *dev,
-					   struct list_head *list);
 extern void iommu_set_default_passthrough(bool cmd_line);
 extern void iommu_set_default_translated(bool cmd_line);
 extern bool iommu_default_passthrough(void);