Re: [PATCH v3 1/4] OMAP_VOUT: Fix check in reqbuf for buf_size allocation

[Archit Taneja <archit@xxxxxx>]

Hi,

On Tuesday 27 September 2011 12:49 PM, Hiremath, Vaibhav wrote:
> > -----Original Message-----
> > From: Taneja, Archit
> > Sent: Monday, September 26, 2011 5:29 PM
> > To: Hiremath, Vaibhav
> > Cc: Valkeinen, Tomi; linux-omap@xxxxxxxxxxxxxxx; Semwal, Sumit; linux-
> > media@xxxxxxxxxxxxxxx; Taneja, Archit
> > Subject: [PATCH v3 1/4] OMAP_VOUT: Fix check in reqbuf for buf_size
> > allocation
> >
> > The commit 383e4f69879d11c86ebdd38b3356f6d0690fb4cc makes reqbuf prevent
> > requesting a larger size buffer than what is allocated at kernel boot
> > during
> > omap_vout_probe.
> >
> > The requested size is compared with vout->buffer_size, this isn't correct
> > as
> > vout->buffer_size is later set to the size requested in reqbuf. When the
> > video
> > device is opened the next time, this check will prevent us to allocate a
> > buffer
> > which is larger than what we requested the last time.
> >
> > Don't use vout->buffer_size, always check with the parameters
> > video1_bufsize
> > or video2_bufsize.
> >
> > Signed-off-by: Archit Taneja<archit@xxxxxx>
> > ---
> >   drivers/media/video/omap/omap_vout.c |   10 ++++++++--
> >   1 files changed, 8 insertions(+), 2 deletions(-)
> >
> > diff --git a/drivers/media/video/omap/omap_vout.c
> > b/drivers/media/video/omap/omap_vout.c
> > index d9e64f3..16ebff6 100644
> > --- a/drivers/media/video/omap/omap_vout.c
> > +++ b/drivers/media/video/omap/omap_vout.c
> > @@ -664,10 +664,14 @@ static int omap_vout_buffer_setup(struct
> > videobuf_queue *q, unsigned int *count,
> >   	u32 phy_addr = 0, virt_addr = 0;
> >   	struct omap_vout_device *vout = q->priv_data;
> >   	struct omapvideo_info *ovid =&vout->vid_info;
> > +	int vid_max_buf_size;
> >
> >   	if (!vout)
> >   		return -EINVAL;
> >
> > +	vid_max_buf_size = vout->vid == OMAP_VIDEO1 ? video1_bufsize :
> > +		video2_bufsize;
> > +
> >   	if (V4L2_BUF_TYPE_VIDEO_OUTPUT != q->type)
> >   		return -EINVAL;
> >
> > @@ -690,7 +694,7 @@ static int omap_vout_buffer_setup(struct
> > videobuf_queue *q, unsigned int *count,
> >   		video1_numbuffers : video2_numbuffers;
> >
> >   	/* Check the size of the buffer */
> > -	if (*size>  vout->buffer_size) {
> > +	if (*size>  vid_max_buf_size) {
> >   		v4l2_err(&vout->vid_dev->v4l2_dev,
> >   				"buffer allocation mismatch [%u] [%u]\n",
> >   				*size, vout->buffer_size);
> > @@ -865,6 +869,8 @@ static int omap_vout_mmap(struct file *file, struct
> > vm_area_struct *vma)
> >   	unsigned long size = (vma->vm_end - vma->vm_start);
> >   	struct omap_vout_device *vout = file->private_data;
> >   	struct videobuf_queue *q =&vout->vbq;
> > +	int vid_max_buf_size = vout->vid == OMAP_VIDEO1 ? video1_bufsize :
> > +		video2_bufsize;
> >
> >   	v4l2_dbg(1, debug,&vout->vid_dev->v4l2_dev,
> >   			" %s pgoff=0x%lx, start=0x%lx, end=0x%lx\n", __func__,
> > @@ -887,7 +893,7 @@ static int omap_vout_mmap(struct file *file, struct
> > vm_area_struct *vma)
> >   		return -EINVAL;
> >   	}
> >   	/* Check the size of the buffer */
> > -	if (size>  vout->buffer_size) {
> > +	if (size>  vid_max_buf_size) {
>
> I think we agreed in your last version patch patch-series that, the check in mmap should be against vout->buffer_size. Am I missing something here?

I totally missed this out for some reason. I'll correct this in the next 
set. Sorry about this.

Archit

> Thanks,
> Vaibhav
>
> >   		v4l2_err(&vout->vid_dev->v4l2_dev,
> >   				"insufficient memory [%lu] [%u]\n",
> >   				size, vout->buffer_size);
> > --
> > 1.7.1

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