diff --git a/drivers/firewire/core-cdev.c b/drivers/firewire/core-cdev.c
index 2e6b245..2783f69 100644
--- a/drivers/firewire/core-cdev.c
+++ b/drivers/firewire/core-cdev.c
@@ -22,6 +22,7 @@
 #include <linux/compat.h>
 #include <linux/delay.h>
 #include <linux/device.h>
+#include <linux/dma-mapping.h>
 #include <linux/errno.h>
 #include <linux/firewire.h>
 #include <linux/firewire-cdev.h>
@@ -70,6 +71,7 @@
 	u64 iso_closure;
 	struct fw_iso_buffer buffer;
 	unsigned long vm_start;
+	bool buffer_is_mapped;
 
 	struct list_head phy_receiver_link;
 	u64 phy_receiver_closure;
@@ -959,11 +961,20 @@
 		    sizeof(e->interrupt), NULL, 0);
 }
 
+static enum dma_data_direction iso_dma_direction(struct fw_iso_context *context)
+{
+		if (context->type == FW_ISO_CONTEXT_TRANSMIT)
+			return DMA_TO_DEVICE;
+		else
+			return DMA_FROM_DEVICE;
+}
+
 static int ioctl_create_iso_context(struct client *client, union ioctl_arg *arg)
 {
 	struct fw_cdev_create_iso_context *a = &arg->create_iso_context;
 	struct fw_iso_context *context;
 	fw_iso_callback_t cb;
+	int ret;
 
 	BUILD_BUG_ON(FW_CDEV_ISO_CONTEXT_TRANSMIT != FW_ISO_CONTEXT_TRANSMIT ||
 		     FW_CDEV_ISO_CONTEXT_RECEIVE  != FW_ISO_CONTEXT_RECEIVE  ||
@@ -1004,8 +1015,21 @@
 	if (client->iso_context != NULL) {
 		spin_unlock_irq(&client->lock);
 		fw_iso_context_destroy(context);
+
 		return -EBUSY;
 	}
+	if (!client->buffer_is_mapped) {
+		ret = fw_iso_buffer_map_dma(&client->buffer,
+					    client->device->card,
+					    iso_dma_direction(context));
+		if (ret < 0) {
+			spin_unlock_irq(&client->lock);
+			fw_iso_context_destroy(context);
+
+			return ret;
+		}
+		client->buffer_is_mapped = true;
+	}
 	client->iso_closure = a->closure;
 	client->iso_context = context;
 	spin_unlock_irq(&client->lock);
@@ -1651,7 +1675,6 @@
 static int fw_device_op_mmap(struct file *file, struct vm_area_struct *vma)
 {
 	struct client *client = file->private_data;
-	enum dma_data_direction direction;
 	unsigned long size;
 	int page_count, ret;
 
@@ -1674,20 +1697,28 @@
 	if (size & ~PAGE_MASK)
 		return -EINVAL;
 
-	if (vma->vm_flags & VM_WRITE)
-		direction = DMA_TO_DEVICE;
-	else
-		direction = DMA_FROM_DEVICE;
-
-	ret = fw_iso_buffer_init(&client->buffer, client->device->card,
-				 page_count, direction);
+	ret = fw_iso_buffer_alloc(&client->buffer, page_count);
 	if (ret < 0)
 		return ret;
 
-	ret = fw_iso_buffer_map(&client->buffer, vma);
+	spin_lock_irq(&client->lock);
+	if (client->iso_context) {
+		ret = fw_iso_buffer_map_dma(&client->buffer,
+				client->device->card,
+				iso_dma_direction(client->iso_context));
+		client->buffer_is_mapped = (ret == 0);
+	}
+	spin_unlock_irq(&client->lock);
 	if (ret < 0)
-		fw_iso_buffer_destroy(&client->buffer, client->device->card);
+		goto fail;
 
+	ret = fw_iso_buffer_map_vma(&client->buffer, vma);
+	if (ret < 0)
+		goto fail;
+
+	return 0;
+ fail:
+	fw_iso_buffer_destroy(&client->buffer, client->device->card);
 	return ret;
 }
 
diff --git a/drivers/firewire/core-iso.c b/drivers/firewire/core-iso.c
index d156582..8382e27 100644
--- a/drivers/firewire/core-iso.c
+++ b/drivers/firewire/core-iso.c
@@ -39,52 +39,73 @@
  * Isochronous DMA context management
  */
 
-int fw_iso_buffer_init(struct fw_iso_buffer *buffer, struct fw_card *card,
-		       int page_count, enum dma_data_direction direction)
+int fw_iso_buffer_alloc(struct fw_iso_buffer *buffer, int page_count)
 {
-	int i, j;
-	dma_addr_t address;
+	int i;
 
-	buffer->page_count = page_count;
-	buffer->direction = direction;
-
+	buffer->page_count = 0;
+	buffer->page_count_mapped = 0;
 	buffer->pages = kmalloc(page_count * sizeof(buffer->pages[0]),
 				GFP_KERNEL);
 	if (buffer->pages == NULL)
-		goto out;
+		return -ENOMEM;
 
-	for (i = 0; i < buffer->page_count; i++) {
+	for (i = 0; i < page_count; i++) {
 		buffer->pages[i] = alloc_page(GFP_KERNEL | GFP_DMA32 | __GFP_ZERO);
 		if (buffer->pages[i] == NULL)
-			goto out_pages;
-
-		address = dma_map_page(card->device, buffer->pages[i],
-				       0, PAGE_SIZE, direction);
-		if (dma_mapping_error(card->device, address)) {
-			__free_page(buffer->pages[i]);
-			goto out_pages;
-		}
-		set_page_private(buffer->pages[i], address);
+			break;
+	}
+	buffer->page_count = i;
+	if (i < page_count) {
+		fw_iso_buffer_destroy(buffer, NULL);
+		return -ENOMEM;
 	}
 
 	return 0;
+}
 
- out_pages:
-	for (j = 0; j < i; j++) {
-		address = page_private(buffer->pages[j]);
-		dma_unmap_page(card->device, address,
-			       PAGE_SIZE, direction);
-		__free_page(buffer->pages[j]);
+int fw_iso_buffer_map_dma(struct fw_iso_buffer *buffer, struct fw_card *card,
+			  enum dma_data_direction direction)
+{
+	dma_addr_t address;
+	int i;
+
+	buffer->direction = direction;
+
+	for (i = 0; i < buffer->page_count; i++) {
+		address = dma_map_page(card->device, buffer->pages[i],
+				       0, PAGE_SIZE, direction);
+		if (dma_mapping_error(card->device, address))
+			break;
+
+		set_page_private(buffer->pages[i], address);
 	}
-	kfree(buffer->pages);
- out:
-	buffer->pages = NULL;
+	buffer->page_count_mapped = i;
+	if (i < buffer->page_count)
+		return -ENOMEM;
 
-	return -ENOMEM;
+	return 0;
+}
+
+int fw_iso_buffer_init(struct fw_iso_buffer *buffer, struct fw_card *card,
+		       int page_count, enum dma_data_direction direction)
+{
+	int ret;
+
+	ret = fw_iso_buffer_alloc(buffer, page_count);
+	if (ret < 0)
+		return ret;
+
+	ret = fw_iso_buffer_map_dma(buffer, card, direction);
+	if (ret < 0)
+		fw_iso_buffer_destroy(buffer, card);
+
+	return ret;
 }
 EXPORT_SYMBOL(fw_iso_buffer_init);
 
-int fw_iso_buffer_map(struct fw_iso_buffer *buffer, struct vm_area_struct *vma)
+int fw_iso_buffer_map_vma(struct fw_iso_buffer *buffer,
+			  struct vm_area_struct *vma)
 {
 	unsigned long uaddr;
 	int i, err;
@@ -107,15 +128,18 @@
 	int i;
 	dma_addr_t address;
 
-	for (i = 0; i < buffer->page_count; i++) {
+	for (i = 0; i < buffer->page_count_mapped; i++) {
 		address = page_private(buffer->pages[i]);
 		dma_unmap_page(card->device, address,
 			       PAGE_SIZE, buffer->direction);
-		__free_page(buffer->pages[i]);
 	}
+	for (i = 0; i < buffer->page_count; i++)
+		__free_page(buffer->pages[i]);
 
 	kfree(buffer->pages);
 	buffer->pages = NULL;
+	buffer->page_count = 0;
+	buffer->page_count_mapped = 0;
 }
 EXPORT_SYMBOL(fw_iso_buffer_destroy);
 
diff --git a/drivers/firewire/core.h b/drivers/firewire/core.h
index 9047f55..94257ae 100644
--- a/drivers/firewire/core.h
+++ b/drivers/firewire/core.h
@@ -3,6 +3,7 @@
 
 #include <linux/compiler.h>
 #include <linux/device.h>
+#include <linux/dma-mapping.h>
 #include <linux/fs.h>
 #include <linux/list.h>
 #include <linux/idr.h>
@@ -169,7 +170,11 @@
 
 /* -iso */
 
-int fw_iso_buffer_map(struct fw_iso_buffer *buffer, struct vm_area_struct *vma);
+int fw_iso_buffer_alloc(struct fw_iso_buffer *buffer, int page_count);
+int fw_iso_buffer_map_dma(struct fw_iso_buffer *buffer, struct fw_card *card,
+			  enum dma_data_direction direction);
+int fw_iso_buffer_map_vma(struct fw_iso_buffer *buffer,
+			  struct vm_area_struct *vma);
 
 
 /* -topology */