1 files changed, 26 insertions, 45 deletions

diff --git a/drivers/firewire/core-cdev.c b/drivers/firewire/core-cdev.c
index 49dc1612c691..9e964fdd175c 100644
--- a/drivers/firewire/core-cdev.c
+++ b/drivers/firewire/core-cdev.c
@@ -63,10 +63,10 @@ struct client {
 	u64 bus_reset_closure;
 
 	struct fw_iso_context *iso_context;
+	struct mutex iso_context_mutex;
 	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;
@@ -306,6 +306,7 @@ static int fw_device_op_open(struct inode *inode, struct file *file)
 	INIT_LIST_HEAD(&client->phy_receiver_link);
 	INIT_LIST_HEAD(&client->link);
 	kref_init(&client->kref);
+	mutex_init(&client->iso_context_mutex);
 
 	file->private_data = client;
 
@@ -1025,25 +1026,10 @@ static enum dma_data_direction iso_dma_direction(struct fw_iso_context *context)
 			return DMA_FROM_DEVICE;
 }
 
-static struct fw_iso_context *fw_iso_mc_context_create(struct fw_card *card,
-						fw_iso_mc_callback_t callback,
-						void *callback_data)
-{
-	struct fw_iso_context *ctx;
-
-	ctx = fw_iso_context_create(card, FW_ISO_CONTEXT_RECEIVE_MULTICHANNEL,
-				    0, 0, 0, NULL, callback_data);
-	if (!IS_ERR(ctx))
-		ctx->callback.mc = callback;
-
-	return ctx;
-}
-
 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;
-	union fw_iso_callback cb;
 	int ret;
 
 	BUILD_BUG_ON(FW_CDEV_ISO_CONTEXT_TRANSMIT != FW_ISO_CONTEXT_TRANSMIT ||
@@ -1055,20 +1041,15 @@ static int ioctl_create_iso_context(struct client *client, union ioctl_arg *arg)
 	case FW_ISO_CONTEXT_TRANSMIT:
 		if (a->speed > SCODE_3200 || a->channel > 63)
 			return -EINVAL;
-
-		cb.sc = iso_callback;
 		break;
 
 	case FW_ISO_CONTEXT_RECEIVE:
 		if (a->header_size < 4 || (a->header_size & 3) ||
 		    a->channel > 63)
 			return -EINVAL;
-
-		cb.sc = iso_callback;
 		break;
 
 	case FW_ISO_CONTEXT_RECEIVE_MULTICHANNEL:
-		cb.mc = iso_mc_callback;
 		break;
 
 	default:
@@ -1076,38 +1057,36 @@ static int ioctl_create_iso_context(struct client *client, union ioctl_arg *arg)
 	}
 
 	if (a->type == FW_ISO_CONTEXT_RECEIVE_MULTICHANNEL)
-		context = fw_iso_mc_context_create(client->device->card, cb.mc,
-						   client);
+		context = fw_iso_mc_context_create(client->device->card, iso_mc_callback, client);
 	else
-		context = fw_iso_context_create(client->device->card, a->type,
-						a->channel, a->speed,
-						a->header_size, cb.sc, client);
+		context = fw_iso_context_create(client->device->card, a->type, a->channel, a->speed,
+						a->header_size, iso_callback, client);
 	if (IS_ERR(context))
 		return PTR_ERR(context);
 	if (client->version < FW_CDEV_VERSION_AUTO_FLUSH_ISO_OVERFLOW)
-		context->drop_overflow_headers = true;
+		context->flags |= FW_ISO_CONTEXT_FLAG_DROP_OVERFLOW_HEADERS;
 
 	// We only support one context at this time.
-	guard(spinlock_irq)(&client->lock);
-
-	if (client->iso_context != NULL) {
-		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) {
+	scoped_guard(mutex, &client->iso_context_mutex) {
+		if (client->iso_context != NULL) {
 			fw_iso_context_destroy(context);
 
-			return ret;
+			return -EBUSY;
+		}
+		// The DMA mapping operation is available if the buffer is already allocated by
+		// mmap(2) system call. If not, it is delegated to the system call.
+		if (client->buffer.pages && !client->buffer.dma_addrs) {
+			ret = fw_iso_buffer_map_dma(&client->buffer, client->device->card,
+						    iso_dma_direction(context));
+			if (ret < 0) {
+				fw_iso_context_destroy(context);
+
+				return ret;
+			}
 		}
-		client->buffer_is_mapped = true;
+		client->iso_closure = a->closure;
+		client->iso_context = context;
 	}
-	client->iso_closure = a->closure;
-	client->iso_context = context;
 
 	a->handle = 0;
 
@@ -1826,13 +1805,14 @@ static int fw_device_op_mmap(struct file *file, struct vm_area_struct *vma)
 	if (ret < 0)
 		return ret;
 
-	scoped_guard(spinlock_irq, &client->lock) {
+	scoped_guard(mutex, &client->iso_context_mutex) {
+		// The direction of DMA can be determined if the isochronous context is already
+		// allocated. If not, the DMA mapping operation is postponed after the allocation.
 		if (client->iso_context) {
 			ret = fw_iso_buffer_map_dma(&client->buffer, client->device->card,
 						    iso_dma_direction(client->iso_context));
 			if (ret < 0)
 				goto fail;
-			client->buffer_is_mapped = true;
 		}
 	}
 
@@ -1879,6 +1859,7 @@ static int fw_device_op_release(struct inode *inode, struct file *file)
 
 	if (client->iso_context)
 		fw_iso_context_destroy(client->iso_context);
+	mutex_destroy(&client->iso_context_mutex);
 
 	if (client->buffer.pages)
 		fw_iso_buffer_destroy(&client->buffer, client->device->card);