Hi Laurent,
On Fri, Oct 09, 2020 at 03:44:12AM +0300, Laurent Pinchart wrote:
> Hi Sakari,
>
> Thank you for the patch.
Thanks for the review!
>
> On Thu, Oct 08, 2020 at 11:47:46PM +0300, Sakari Ailus wrote:
> > Pad format can be accessed from user space. Serialise access to it.
> >
> > Fixes: c2a6a07afe4a ("media: intel-ipu3: cio2: add new MIPI-CSI2 driver")
> > Signed-off-by: Sakari Ailus <sakari.ailus@xxxxxxxxxxxxxxx>
> > ---
> > drivers/media/pci/intel/ipu3/ipu3-cio2.c | 11 +++++++++++
> > drivers/media/pci/intel/ipu3/ipu3-cio2.h | 1 +
> > 2 files changed, 12 insertions(+)
> >
> > diff --git a/drivers/media/pci/intel/ipu3/ipu3-cio2.c b/drivers/media/pci/intel/ipu3/ipu3-cio2.c
> > index afa472026ba4..9c7b527a8800 100644
> > --- a/drivers/media/pci/intel/ipu3/ipu3-cio2.c
> > +++ b/drivers/media/pci/intel/ipu3/ipu3-cio2.c
> > @@ -1233,11 +1233,15 @@ static int cio2_subdev_get_fmt(struct v4l2_subdev *sd,
> > {
> > struct cio2_queue *q = container_of(sd, struct cio2_queue, subdev);
> >
> > + mutex_lock(&q->subdev_lock);
> > +
> > if (fmt->which == V4L2_SUBDEV_FORMAT_TRY)
> > fmt->format = *v4l2_subdev_get_try_format(sd, cfg, fmt->pad);
> > else
> > fmt->format = q->subdev_fmt;
> >
> > + mutex_unlock(&q->subdev_lock);
> > +
> > return 0;
> > }
> >
> > @@ -1261,6 +1265,8 @@ static int cio2_subdev_set_fmt(struct v4l2_subdev *sd,
> > if (fmt->pad == CIO2_PAD_SOURCE)
> > return cio2_subdev_get_fmt(sd, cfg, fmt);
> >
> > + mutex_lock(&q->subdev_lock);
> > +
> > if (fmt->which == V4L2_SUBDEV_FORMAT_TRY) {
> > *v4l2_subdev_get_try_format(sd, cfg, fmt->pad) = fmt->format;
> > } else {
> > @@ -1271,6 +1277,8 @@ static int cio2_subdev_set_fmt(struct v4l2_subdev *sd,
> > fmt->format = q->subdev_fmt;
> > }
>
> Not a candidate for this patch, but this should restrict the pixel
> format and size to supported values.
Yes.
>
> >
> > + mutex_unlock(&q->subdev_lock);
> > +
> > return 0;
> > }
> >
> > @@ -1529,6 +1537,7 @@ static int cio2_queue_init(struct cio2_device *cio2, struct cio2_queue *q)
> >
> > /* Initialize miscellaneous variables */
> > mutex_init(&q->lock);
> > + mutex_init(&q->subdev_lock);
> >
> > /* Initialize formats to default values */
> > fmt = &q->subdev_fmt;
> > @@ -1646,6 +1655,7 @@ static int cio2_queue_init(struct cio2_device *cio2, struct cio2_queue *q)
> > cio2_fbpt_exit(q, &cio2->pci_dev->dev);
> > fail_fbpt:
> > mutex_destroy(&q->lock);
> > + mutex_destroy(&q->subdev_lock);
> >
> > return r;
> > }
> > @@ -1658,6 +1668,7 @@ static void cio2_queue_exit(struct cio2_device *cio2, struct cio2_queue *q)
> > media_entity_cleanup(&q->subdev.entity);
> > cio2_fbpt_exit(q, &cio2->pci_dev->dev);
> > mutex_destroy(&q->lock);
> > + mutex_destroy(&q->subdev_lock);
> > }
> >
> > static int cio2_queues_init(struct cio2_device *cio2)
> > diff --git a/drivers/media/pci/intel/ipu3/ipu3-cio2.h b/drivers/media/pci/intel/ipu3/ipu3-cio2.h
> > index 549b08f88f0c..df0247326a1d 100644
> > --- a/drivers/media/pci/intel/ipu3/ipu3-cio2.h
> > +++ b/drivers/media/pci/intel/ipu3/ipu3-cio2.h
> > @@ -335,6 +335,7 @@ struct cio2_queue {
> >
> > /* Subdev, /dev/v4l-subdevX */
> > struct v4l2_subdev subdev;
> > + struct mutex subdev_lock;
>
> Can you add a small comment to tell which field(s) this lock protects ?
How about:
/* Serialise access to subdev_fmt field */
Currently it's just that, but I feel locking in this driver would generally
benefit from refactoring. That can wait a little though as it's not an
acute problem.
>
> Reviewed-by: Laurent Pinchart <laurent.pinchart@xxxxxxxxxxxxxxxx>
>
> > struct media_pad subdev_pads[CIO2_PADS];
> > struct v4l2_mbus_framefmt subdev_fmt;
> > atomic_t frame_sequence;
>
> --
> Regards,
>
> Laurent Pinchart
--
Sakari Ailus
