diff --git a/arch/powerpc/platforms/pseries/iommu.c b/arch/powerpc/platforms/pseries/iommu.c
index 4ba2338..e4050f6 100644
--- a/arch/powerpc/platforms/pseries/iommu.c
+++ b/arch/powerpc/platforms/pseries/iommu.c
@@ -285,6 +285,21 @@ struct direct_window {
 	const struct dynamic_dma_window_prop *prop;
 	struct list_head list;
 };
+
+/* Dynamic DMA Window support */
+struct ddw_query_response {
+	u32 windows_available;
+	u32 largest_available_block;
+	u32 page_size;
+	u32 migration_capable;
+};
+
+struct ddw_create_response {
+	u32 liobn;
+	u32 addr_hi;
+	u32 addr_lo;
+};
+
 static LIST_HEAD(direct_window_list);
 /* prevents races between memory on/offline and window creation */
 static DEFINE_SPINLOCK(direct_window_list_lock);
@@ -323,7 +338,7 @@ static int tce_clearrange_multi_pSeriesLP(unsigned long start_pfn,
 		dma_offset = next + be64_to_cpu(maprange->dma_base);
 
 		rc = plpar_tce_stuff((u64)be32_to_cpu(maprange->liobn),
-					    (u64)dma_offset,
+					     dma_offset,
 					     0, limit);
 		num_tce -= limit;
 	} while (num_tce > 0 && !rc);
@@ -383,7 +398,7 @@ static int tce_setrange_multi_pSeriesLP(unsigned long start_pfn,
 		}
 
 		rc = plpar_tce_put_indirect(liobn,
-					    (u64)dma_offset,
+					    dma_offset,
 					    (u64)virt_to_abs(tcep),
 					    limit);
 
@@ -731,7 +746,8 @@ static u64 dupe_ddw_if_kexec(struct pci_dev *dev, struct device_node *pdn)
 	return dma_addr;
 }
 
-static int query_ddw(struct pci_dev *dev, const u32 *ddr_avail, u32 *query)
+static int query_ddw(struct pci_dev *dev, const u32 *ddr_avail,
+			struct ddw_query_response *query)
 {
 	struct device_node *dn;
 	struct pci_dn *pcidn;
@@ -751,7 +767,7 @@ static int query_ddw(struct pci_dev *dev, const u32 *ddr_avail, u32 *query)
 	if (pcidn->eeh_pe_config_addr)
 		cfg_addr = pcidn->eeh_pe_config_addr;
 	buid = pcidn->phb->buid;
-	ret = rtas_call(ddr_avail[0], 3, 5, query,
+	ret = rtas_call(ddr_avail[0], 3, 5, (u32 *)query,
 		  cfg_addr, BUID_HI(buid), BUID_LO(buid));
 	dev_info(&dev->dev, "ibm,query-pe-dma-windows(%x) %x %x %x"
 		" returned %d\n", ddr_avail[0], cfg_addr, BUID_HI(buid),
@@ -759,7 +775,9 @@ static int query_ddw(struct pci_dev *dev, const u32 *ddr_avail, u32 *query)
 	return ret;
 }
 
-static int create_ddw(struct pci_dev *dev, const u32 *ddr_avail, u32 *create, int page_shift, int window_shift)
+static int create_ddw(struct pci_dev *dev, const u32 *ddr_avail,
+			struct ddw_create_response *create, int page_shift,
+			int window_shift)
 {
 	struct device_node *dn;
 	struct pci_dn *pcidn;
@@ -782,15 +800,15 @@ static int create_ddw(struct pci_dev *dev, const u32 *ddr_avail, u32 *create, in
 
 	do {
 		/* extra outputs are LIOBN and dma-addr (hi, lo) */
-		ret = rtas_call(ddr_avail[1], 5, 4, &create[0], cfg_addr,
+		ret = rtas_call(ddr_avail[1], 5, 4, (u32 *)create, cfg_addr,
 				BUID_HI(buid), BUID_LO(buid), page_shift, window_shift);
-	} while(rtas_busy_delay(ret));
+	} while (rtas_busy_delay(ret));
 	dev_info(&dev->dev,
 		"ibm,create-pe-dma-window(%x) %x %x %x %x %x returned %d "
 		"(liobn = 0x%x starting addr = %x %x)\n", ddr_avail[1],
 		 cfg_addr, BUID_HI(buid), BUID_LO(buid), page_shift,
-		 window_shift, ret, create[0], create[1], create[2]);
-	
+		 window_shift, ret, create->liobn, create->addr_hi, create->addr_lo);
+
 	return ret;
 }
 
@@ -808,7 +826,8 @@ static int create_ddw(struct pci_dev *dev, const u32 *ddr_avail, u32 *create, in
 static u64 enable_ddw(struct pci_dev *dev, struct device_node *pdn)
 {
 	int len, ret;
-	u32 query[4], create[3];
+	struct ddw_query_response query;
+	struct ddw_create_response create;
 	int page_shift;
 	u64 dma_addr, max_addr;
 	struct device_node *dn;
@@ -846,11 +865,11 @@ static u64 enable_ddw(struct pci_dev *dev, struct device_node *pdn)
 	 * of page sizes: supported and supported for migrate-dma.
 	 */
 	dn = pci_device_to_OF_node(dev);
-	ret = query_ddw(dev, ddr_avail, &query[0]);
+	ret = query_ddw(dev, ddr_avail, &query);
 	if (ret != 0)
 		goto out_unlock;
 
-	if (!query[0]) {
+	if (query.windows_available == 0) {
 		/*
 		 * no additional windows are available for this device.
 		 * We might be able to reallocate the existing window,
@@ -859,23 +878,23 @@ static u64 enable_ddw(struct pci_dev *dev, struct device_node *pdn)
 		dev_dbg(&dev->dev, "no free dynamic windows");
 		goto out_unlock;
 	}
-	if (query[2] & 4) {
+	if (query.page_size & 4) {
 		page_shift = 24; /* 16MB */
-	} else if (query[2] & 2) {
+	} else if (query.page_size & 2) {
 		page_shift = 16; /* 64kB */
-	} else if (query[2] & 1) {
+	} else if (query.page_size & 1) {
 		page_shift = 12; /* 4kB */
 	} else {
 		dev_dbg(&dev->dev, "no supported direct page size in mask %x",
-			  query[2]);
+			  query.page_size);
 		goto out_unlock;
 	}
 	/* verify the window * number of ptes will map the partition */
 	/* check largest block * page size > max memory hotplug addr */
 	max_addr = memory_hotplug_max();
-	if (query[1] < (max_addr >> page_shift)) {
+	if (query.largest_available_block < (max_addr >> page_shift)) {
 		dev_dbg(&dev->dev, "can't map partiton max 0x%llx with %u "
-			  "%llu-sized pages\n", max_addr,  query[1],
+			  "%llu-sized pages\n", max_addr,  query.largest_available_block,
 			  1ULL << page_shift);
 		goto out_unlock;
 	}
@@ -894,19 +913,17 @@ static u64 enable_ddw(struct pci_dev *dev, struct device_node *pdn)
 		goto out_free_prop;
 	}
 
-	ret = create_ddw(dev, ddr_avail, &create[0], page_shift, len);
+	ret = create_ddw(dev, ddr_avail, &create, page_shift, len);
 	if (ret != 0)
 		goto out_free_prop;
 
-	*ddwprop = (struct dynamic_dma_window_prop) {
-		.liobn = cpu_to_be32(create[0]),
-		.dma_base = cpu_to_be64(((u64)create[1] << 32) + (u64)create[2]),
-		.tce_shift = cpu_to_be32(page_shift),
-		.window_shift = cpu_to_be32(len)
-	};
+	ddwprop->liobn = cpu_to_be32(create.liobn);
+	ddwprop->dma_base = cpu_to_be64(of_read_number(&create.addr_hi, 2));
+	ddwprop->tce_shift = cpu_to_be32(page_shift);
+	ddwprop->window_shift = cpu_to_be32(len);
 
 	dev_dbg(&dev->dev, "created tce table LIOBN 0x%x for %s\n",
-		  create[0], dn->full_name);
+		  create.liobn, dn->full_name);
 
 	window = kzalloc(sizeof(*window), GFP_KERNEL);
 	if (!window)
@@ -933,7 +950,7 @@ static u64 enable_ddw(struct pci_dev *dev, struct device_node *pdn)
 	list_add(&window->list, &direct_window_list);
 	spin_unlock(&direct_window_list_lock);
 
-	dma_addr = of_read_number(&create[1], 2);
+	dma_addr = of_read_number(&create.addr_hi, 2);
 	set_dma_offset(&dev->dev, dma_addr);
 	goto out_unlock;
 
@@ -1015,7 +1032,7 @@ static int dma_set_mask_pSeriesLP(struct device *dev, u64 dma_mask)
 		dn = pci_device_to_OF_node(pdev);
 		dev_dbg(dev, "node is %s\n", dn->full_name);
 
-		/* 
+		/*
 		 * the device tree might contain the dma-window properties
 		 * per-device and not neccesarily for the bus. So we need to
 		 * search upwards in the tree until we either hit a dma-window
@@ -1118,7 +1135,15 @@ static int iommu_reconfig_notifier(struct notifier_block *nb, unsigned long acti
 		}
 		spin_unlock(&direct_window_list_lock);
 
-		remove_ddw(np);
+		/*
+		 * Because the notifier runs after isolation of the
+		 * slot, we are guaranteed any DMA window has already
+		 * been revoked and the TCEs have been marked invalid,
+		 * so we don't need a call to remove_ddw(np). However,
+		 * if an additional notifier action is added before the
+		 * isolate call, we should update this code for
+		 * completeness with such a call.
+		 */
 		break;
 	default:
 		err = NOTIFY_DONE;
