Re: [PATCH] videobuf2: call buf_finish() on unprocessed buffers

[Mauro Carvalho Chehab <mchehab@redhat.com>]

Em 24-07-2011 19:10, Pawel Osciak escreveu:
> 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.

Is there any update on this?

Thanks,
Mauro

> -- Best regards, Pawel Osciak On Thu, Jul 14, 2011 at 14:09, Jonathan Corbet <corbet@lwn.net> 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 <corbet@lwn.net>
>> > ---
>> >  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
>> >
>> > --
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