media: dvb-usb-v2: stop using coherent memory for URBs

There's no need to use coherent buffers there. So, let the
DVB core do the allocation. That should give some performance
gain outside x86.
Signed-off-by: NMauro Carvalho Chehab <mchehab@s-opensource.com>
Signed-off-by: NMauro Carvalho Chehab <mchehab+samsung@kernel.org>

drivers/media/usb/dvb-usb-v2/usb_urb.c

@@ -155,8 +155,7 @@ static int usb_urb_alloc_bulk_urbs(struct usb_data_stream *stream)
 				stream->props.u.bulk.buffersize,
 				usb_urb_complete, stream);
 
-		stream->urb_list[i]->transfer_flags = URB_NO_TRANSFER_DMA_MAP;
-		stream->urb_list[i]->transfer_dma = stream->dma_addr[i];
+		stream->urb_list[i]->transfer_flags = URB_FREE_BUFFER;
 		stream->urbs_initialized++;
 	}
 	return 0;
@@ -187,13 +186,12 @@ static int usb_urb_alloc_isoc_urbs(struct usb_data_stream *stream)
 		urb->complete = usb_urb_complete;
 		urb->pipe = usb_rcvisocpipe(stream->udev,
 				stream->props.endpoint);
-		urb->transfer_flags = URB_ISO_ASAP | URB_NO_TRANSFER_DMA_MAP;
+		urb->transfer_flags = URB_ISO_ASAP | URB_FREE_BUFFER;
 		urb->interval = stream->props.u.isoc.interval;
 		urb->number_of_packets = stream->props.u.isoc.framesperurb;
 		urb->transfer_buffer_length = stream->props.u.isoc.framesize *
 				stream->props.u.isoc.framesperurb;
 		urb->transfer_buffer = stream->buf_list[i];
-		urb->transfer_dma = stream->dma_addr[i];
 
 		for (j = 0; j < stream->props.u.isoc.framesperurb; j++) {
 			urb->iso_frame_desc[j].offset = frame_offset;
@@ -212,11 +210,7 @@ static int usb_free_stream_buffers(struct usb_data_stream *stream)
 	if (stream->state & USB_STATE_URB_BUF) {
 		while (stream->buf_num) {
 			stream->buf_num--;
-			dev_dbg(&stream->udev->dev, "%s: free buf=%d\n",
-				__func__, stream->buf_num);
-			usb_free_coherent(stream->udev, stream->buf_size,
-					  stream->buf_list[stream->buf_num],
-					  stream->dma_addr[stream->buf_num]);
+			stream->buf_list[stream->buf_num] = NULL;
 		}
 	}
 
@@ -236,9 +230,7 @@ static int usb_alloc_stream_buffers(struct usb_data_stream *stream, int num,
 			__func__,  num * size);
 
 	for (stream->buf_num = 0; stream->buf_num < num; stream->buf_num++) {
-		stream->buf_list[stream->buf_num] = usb_alloc_coherent(
-				stream->udev, size, GFP_ATOMIC,
-				&stream->dma_addr[stream->buf_num]);
+		stream->buf_list[stream->buf_num] = kzalloc(size, GFP_ATOMIC);
 		if (!stream->buf_list[stream->buf_num]) {
 			dev_dbg(&stream->udev->dev, "%s: alloc buf=%d failed\n",
 					__func__, stream->buf_num);
@@ -250,7 +242,6 @@ static int usb_alloc_stream_buffers(struct usb_data_stream *stream, int num,
 				__func__, stream->buf_num,
 				stream->buf_list[stream->buf_num],
 				(long long)stream->dma_addr[stream->buf_num]);
-		memset(stream->buf_list[stream->buf_num], 0, size);
 		stream->state |= USB_STATE_URB_BUF;
 	}