From mboxrd@z Thu Jan 1 00:00:00 1970 Return-path: Received: from mail.kapsi.fi ([91.232.154.25]:56167 "EHLO mail.kapsi.fi" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751534AbeCMTW7 (ORCPT ); Tue, 13 Mar 2018 15:22:59 -0400 Subject: Re: [PATCH] media: dvb-usb-v2: stop using coherent memory for URBs To: Mauro Carvalho Chehab , Linux Media Mailing List Cc: Mauro Carvalho Chehab References: <6a131c6ca8afe5d000b9cbfadff96ea72f200852.1520536139.git.mchehab@s-opensource.com> From: Antti Palosaari Message-ID: <28084fba-62ba-6f1a-28fb-1aabbb92d4e5@iki.fi> Date: Tue, 13 Mar 2018 21:22:55 +0200 MIME-Version: 1.0 In-Reply-To: <6a131c6ca8afe5d000b9cbfadff96ea72f200852.1520536139.git.mchehab@s-opensource.com> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 7bit Sender: linux-media-owner@vger.kernel.org List-ID: On 03/08/2018 09:09 PM, Mauro Carvalho Chehab wrote: > 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. Hello! I am not familiar with that change, but I think you know what you do. Feel free to apply! regards Antti > > Signed-off-by: Mauro Carvalho Chehab > --- > drivers/media/usb/dvb-usb-v2/usb_urb.c | 17 ++++------------- > 1 file changed, 4 insertions(+), 13 deletions(-) > > diff --git a/drivers/media/usb/dvb-usb-v2/usb_urb.c b/drivers/media/usb/dvb-usb-v2/usb_urb.c > index dce2b97efce4..b0499f95ec45 100644 > --- a/drivers/media/usb/dvb-usb-v2/usb_urb.c > +++ b/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; > } > > -- http://palosaari.fi/