From mboxrd@z Thu Jan 1 00:00:00 1970 Return-path: Received: from mail-qw0-f46.google.com ([209.85.216.46]:48071 "EHLO mail-qw0-f46.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752498Ab1GXWKq convert rfc822-to-8bit (ORCPT ); Sun, 24 Jul 2011 18:10:46 -0400 Received: by qwk3 with SMTP id 3so1803931qwk.19 for ; Sun, 24 Jul 2011 15:10:45 -0700 (PDT) MIME-Version: 1.0 In-Reply-To: <20110714150934.74777696@bike.lwn.net> References: <20110714150934.74777696@bike.lwn.net> From: Pawel Osciak Date: Sun, 24 Jul 2011 15:10:25 -0700 Message-ID: Subject: Re: [PATCH] videobuf2: call buf_finish() on unprocessed buffers To: Jonathan Corbet Cc: linux-media@vger.kernel.org, Marek Szyprowski , Mauro Carvalho Chehab Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 8BIT Sender: linux-media-owner@vger.kernel.org List-ID: Hi Jon, There is a misunderstanding here. This patch will call buf_finish for some buffers twice. A buffer does not get removed from queued_list even if it is on the done_list. A buffer gets into the queued_list on qbuf, gets into the done_list after an operation is finished and is removed from both lists on dqbuf. This means that you shouldn't call buf_finish for buffers on both lists, only for all buffers in the queued_list, as it is a superset of both. -- Best regards, Pawel Osciak On Thu, Jul 14, 2011 at 14:09, Jonathan Corbet wrote: > When user space stops streaming, there may be buffers which have been given > to buf_prepare() and which may or may not have been passed to buf_queue(). > The videobuf2 core simply takes those buffers back; if buf_prepare() does > work that needs cleaning up (like setting up a DMA mapping), that cleanup > will not happen. > > This patch establishes a simple contract with drivers: buffers given to > buf_prepare() will eventually see a buf_finish() call. > > Signed-off-by: Jonathan Corbet > --- >  drivers/media/video/videobuf2-core.c |    8 +++++++- >  1 files changed, 7 insertions(+), 1 deletions(-) > > diff --git a/drivers/media/video/videobuf2-core.c b/drivers/media/video/videobuf2-core.c > index 6ba1461..2ba08ab 100644 > --- a/drivers/media/video/videobuf2-core.c > +++ b/drivers/media/video/videobuf2-core.c > @@ -1177,6 +1177,7 @@ EXPORT_SYMBOL_GPL(vb2_streamon); >  */ >  static void __vb2_queue_cancel(struct vb2_queue *q) >  { > +       struct vb2_buffer *vb; >        unsigned int i; > >        /* > @@ -1188,13 +1189,18 @@ static void __vb2_queue_cancel(struct vb2_queue *q) >        q->streaming = 0; > >        /* > -        * Remove all buffers from videobuf's list... > +        * Remove all buffers from videobuf's list...  Give the driver > +        * a chance to clean them up first, though. >         */ > +       list_for_each_entry(vb, &q->queued_list, queued_entry) > +               call_qop(q, buf_finish, vb); >        INIT_LIST_HEAD(&q->queued_list); >        /* >         * ...and done list; userspace will not receive any buffers it >         * has not already dequeued before initiating cancel. >         */ > +       list_for_each_entry(vb, &q->done_list, done_entry) > +               call_qop(q, buf_finish, vb); >        INIT_LIST_HEAD(&q->done_list); >        wake_up_all(&q->done_wq); > > -- > 1.7.6 > > -- > To unsubscribe from this list: send the line "unsubscribe linux-media" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at  http://vger.kernel.org/majordomo-info.html >