iommu: Pass struct iommu_iotlb_gather to ->unmap() and ->iotlb_sync()

To allow IOMMU drivers to batch up TLB flushing operations and postpone
them until ->iotlb_sync() is called, extend the prototypes for the
->unmap() and ->iotlb_sync() IOMMU ops callbacks to take a pointer to
the current iommu_iotlb_gather structure.

All affected IOMMU drivers are updated, but there should be no
functional change since the extra parameter is ignored for now.

Signed-off-by: Will Deacon <will@kernel.org>

drivers/iommu/virtio-iommu.c

@@ -742,7 +742,7 @@ static int viommu_map(struct iommu_domain *domain, unsigned long iova,
 }
 
 static size_t viommu_unmap(struct iommu_domain *domain, unsigned long iova,
-			   size_t size)
+			   size_t size, struct iommu_iotlb_gather *gather)
 {
 	int ret = 0;
 	size_t unmapped;
@@ -788,7 +788,8 @@ static phys_addr_t viommu_iova_to_phys(struct iommu_domain *domain,
 	return paddr;
 }
 
-static void viommu_iotlb_sync(struct iommu_domain *domain)
+static void viommu_iotlb_sync(struct iommu_domain *domain,
+			      struct iommu_iotlb_gather *gather)
 {
 	struct viommu_domain *vdomain = to_viommu_domain(domain);