Re: [PATCH 1/1] videobuf: Initialize lists in videobuf_buffer.

From: Laurent Pinchart
Date: Wed Nov 17 2010 - 07:47:57 EST


Hi Hans,

On Wednesday 17 November 2010 08:11:06 Hans Verkuil wrote:
> On Wednesday, November 17, 2010 02:38:09 Andrew Chew wrote:
> > > > diff --git a/drivers/media/video/videobuf-dma-contig.c
> > >
> > > b/drivers/media/video/videobuf-dma-contig.c
> > >
> > > > index c969111..f7e0f86 100644
> > > > --- a/drivers/media/video/videobuf-dma-contig.c
> > > > +++ b/drivers/media/video/videobuf-dma-contig.c
> > > > @@ -193,6 +193,8 @@ static struct videobuf_buffer
> > >
> > > *__videobuf_alloc_vb(size_t size)
> > >
> > > > if (vb) {
> > > >
> > > > mem = vb->priv = ((char *)vb) + size;
> > > > mem->magic = MAGIC_DC_MEM;
> > > >
> > > > + INIT_LIST_HEAD(&vb->stream);
> > > > + INIT_LIST_HEAD(&vb->queue);
> > >
> > > i think it no need to be init, it just a list-entry.
> >
> > Okay, if that's really the case, then sh_mobile_ceu_camera.c,
> > pxa_camera.c, mx1_camera.c, mx2_camera.c, and omap1_camera.c needs to be
> > fixed to remove that WARN_ON(!list_empty(&vb->queue)); in their
> > videobuf_prepare() methods, because those WARN_ON's are assuming that
> > vb->queue is properly initialized as a list head.
> >
> > Which will it be?
>
> These list entries need to be inited. It is bad form to have uninitialized
> list entries. It is not as if this is a big deal to initialize them
> properly.

I disagree with that. List heads must be initialized, but there's no point in
initializing list entries.

--
Regards,

Laurent Pinchart
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