Hi Jacopo,
Thanks for the review!
On Fri, Jun 14, 2019 at 06:01:41PM +0200, Jacopo Mondi wrote:
> Hi Sakari,
>
> On Thu, Jun 06, 2019 at 04:02:19PM +0300, Sakari Ailus wrote:
> > The v4l2_async_notifier_add_fwnode_subdev() did not take a reference of
> > the added fwnode, relying on the caller to handle that instead, in essence
> > putting the fwnode to be added if there was an error.
> >
> > As the reference is eventually released during the notifier cleanup, this
> > is not intuitive nor logical. Improve this by always getting a reference
> > when the function succeeds, and the caller releasing the reference when it
> > does not *itself* need it anymore.
> >
> > Luckily, perhaps, there were just a handful of callers using the function.
> >
> > Signed-off-by: Sakari Ailus <sakari.ailus@xxxxxxxxxxxxxxx>
> > ---
> > drivers/media/platform/am437x/am437x-vpfe.c | 5 ++---
> > drivers/media/platform/davinci/vpif_capture.c | 16 ++++++++--------
> > drivers/media/platform/qcom/camss/camss.c | 2 +-
> > drivers/media/platform/xilinx/xilinx-vipp.c | 2 +-
> > drivers/media/v4l2-core/v4l2-async.c | 3 ++-
> > drivers/media/v4l2-core/v4l2-fwnode.c | 23 ++++++-----------------
> > include/media/v4l2-async.h | 5 +++--
> > 7 files changed, 23 insertions(+), 33 deletions(-)
> >
> > diff --git a/drivers/media/platform/am437x/am437x-vpfe.c b/drivers/media/platform/am437x/am437x-vpfe.c
> > index db263c0ce48e..ccdbd9227955 100644
> > --- a/drivers/media/platform/am437x/am437x-vpfe.c
> > +++ b/drivers/media/platform/am437x/am437x-vpfe.c
> > @@ -2505,10 +2505,9 @@ vpfe_get_pdata(struct vpfe_device *vpfe)
> > pdata->asd[i] = v4l2_async_notifier_add_fwnode_subdev(
> > &vpfe->notifier, of_fwnode_handle(rem),
> > sizeof(struct v4l2_async_subdev));
> > - if (IS_ERR(pdata->asd[i])) {
> > - of_node_put(rem);
> > + of_node_put(rem);
> > + if (IS_ERR(pdata->asd[i]))
> > goto cleanup;
> > - }
> > }
> >
> > of_node_put(endpoint);
> > diff --git a/drivers/media/platform/davinci/vpif_capture.c b/drivers/media/platform/davinci/vpif_capture.c
> > index 8fdea45ae090..2a0c3f3fb443 100644
> > --- a/drivers/media/platform/davinci/vpif_capture.c
> > +++ b/drivers/media/platform/davinci/vpif_capture.c
> > @@ -1512,6 +1512,7 @@ static struct vpif_capture_config *
> > vpif_capture_get_pdata(struct platform_device *pdev)
> > {
> > struct device_node *endpoint = NULL;
> > + struct device_node *rem = NULL, *rem_ep = NULL;
> > struct vpif_capture_config *pdata;
> > struct vpif_subdev_info *sdinfo;
> > struct vpif_capture_chan_config *chan;
> > @@ -1542,7 +1543,6 @@ vpif_capture_get_pdata(struct platform_device *pdev)
> >
> > for (i = 0; i < VPIF_CAPTURE_NUM_CHANNELS; i++) {
> > struct v4l2_fwnode_endpoint bus_cfg = { .bus_type = 0 };
> > - struct device_node *rem, *rem_ep;
> > unsigned int flags;
> > int err;
> >
> > @@ -1565,7 +1565,6 @@ vpif_capture_get_pdata(struct platform_device *pdev)
> > of_node_put(rem_ep);
> > goto done;
> > }
> > - of_node_put(rem_ep);
> >
> > sdinfo = &pdata->subdev_info[i];
> > chan = &pdata->chan_config[i];
> > @@ -1573,10 +1572,8 @@ vpif_capture_get_pdata(struct platform_device *pdev)
> > VPIF_CAPTURE_NUM_CHANNELS,
> > sizeof(*chan->inputs),
> > GFP_KERNEL);
> > - if (!chan->inputs) {
> > - of_node_put(rem);
> > + if (!chan->inputs)
> > goto err_cleanup;
> > - }
> >
> > chan->input_count++;
> > chan->inputs[i].input.type = V4L2_INPUT_TYPE_CAMERA;
> > @@ -1588,6 +1585,7 @@ vpif_capture_get_pdata(struct platform_device *pdev)
> > if (err) {
> > dev_err(&pdev->dev, "Could not parse the endpoint\n");
> > of_node_put(rem);
> > + of_node_put(rem_ep);
> > goto done;
> > }
> >
> > @@ -1608,11 +1606,11 @@ vpif_capture_get_pdata(struct platform_device *pdev)
> > pdata->asd[i] = v4l2_async_notifier_add_fwnode_subdev(
> > &vpif_obj.notifier, of_fwnode_handle(rem_ep),
> > sizeof(struct v4l2_async_subdev));
> > - if (IS_ERR(pdata->asd[i])) {
> > - of_node_put(rem);
> > + if (IS_ERR(pdata->asd[i]))
> > goto err_cleanup;
> > - }
> >
> > + of_node_put(rem);
> > + of_node_put(rem_ep);
> > }
> >
> > done:
> > @@ -1624,6 +1622,8 @@ vpif_capture_get_pdata(struct platform_device *pdev)
> > return pdata;
> >
> > err_cleanup:
> > + of_node_put(rem);
> > + of_node_put(rem_ep);
> > of_node_put(endpoint);
> > v4l2_async_notifier_cleanup(&vpif_obj.notifier);
> >
> > diff --git a/drivers/media/platform/qcom/camss/camss.c b/drivers/media/platform/qcom/camss/camss.c
> > index a979f210f441..4ab4a47d34f3 100644
> > --- a/drivers/media/platform/qcom/camss/camss.c
> > +++ b/drivers/media/platform/qcom/camss/camss.c
> > @@ -486,9 +486,9 @@ static int camss_of_parse_ports(struct camss *camss)
> >
> > asd = v4l2_async_notifier_add_fwnode_subdev(
> > &camss->notifier, remote, sizeof(*csd));
> > + fwnode_handle_put(remote);
> > if (IS_ERR(asd)) {
> > ret = PTR_ERR(asd);
> > - fwnode_handle_put(remote);
> > goto err_cleanup;
> > }
> >
> > diff --git a/drivers/media/platform/xilinx/xilinx-vipp.c b/drivers/media/platform/xilinx/xilinx-vipp.c
> > index 41df417153bd..d788f4870a23 100644
> > --- a/drivers/media/platform/xilinx/xilinx-vipp.c
> > +++ b/drivers/media/platform/xilinx/xilinx-vipp.c
> > @@ -392,9 +392,9 @@ static int xvip_graph_parse_one(struct xvip_composite_device *xdev,
> > asd = v4l2_async_notifier_add_fwnode_subdev(
> > &xdev->notifier, remote,
> > sizeof(struct xvip_graph_entity));
> > + fwnode_handle_put(remote);
> > if (IS_ERR(asd)) {
> > ret = PTR_ERR(asd);
> > - fwnode_handle_put(remote);
> > goto err_notifier_cleanup;
> > }
> > }
> > diff --git a/drivers/media/v4l2-core/v4l2-async.c b/drivers/media/v4l2-core/v4l2-async.c
> > index 304969ff3191..dc4e83b4f6ba 100644
> > --- a/drivers/media/v4l2-core/v4l2-async.c
> > +++ b/drivers/media/v4l2-core/v4l2-async.c
> > @@ -596,10 +596,11 @@ v4l2_async_notifier_add_fwnode_subdev(struct v4l2_async_notifier *notifier,
> > return ERR_PTR(-ENOMEM);
> >
> > asd->match_type = V4L2_ASYNC_MATCH_FWNODE;
> > - asd->match.fwnode = fwnode;
> > + asd->match.fwnode = fwnode_handle_get(fwnode);
> >
> > ret = v4l2_async_notifier_add_subdev(notifier, asd);
> > if (ret) {
> > + fwnode_handle_put(fwnode);
> > kfree(asd);
> > return ERR_PTR(ret);
> > }
> > diff --git a/drivers/media/v4l2-core/v4l2-fwnode.c b/drivers/media/v4l2-core/v4l2-fwnode.c
> > index 810b6584b522..b48725824580 100644
> > --- a/drivers/media/v4l2-core/v4l2-fwnode.c
> > +++ b/drivers/media/v4l2-core/v4l2-fwnode.c
> > @@ -780,23 +780,17 @@ static int v4l2_fwnode_reference_parse(struct device *dev,
> > asd = v4l2_async_notifier_add_fwnode_subdev(notifier,
> > args.fwnode,
> > sizeof(*asd));
> > + fwnode_handle_put(args.fwnode);
> > if (IS_ERR(asd)) {
> > - ret = PTR_ERR(asd);
> > /* not an error if asd already exists */
> > - if (ret == -EEXIST) {
> > - fwnode_handle_put(args.fwnode);
> > + if (PTR_ERR(asd) == -EEXIST)
> > continue;
> > - }
> >
> > - goto error;
> > + return PTR_ERR(asd);
> > }
> > }
> >
> > return 0;
> > -
> > -error:
> > - fwnode_handle_put(args.fwnode);
> > - return ret;
> > }
> >
> > /*
> > @@ -1085,22 +1079,17 @@ v4l2_fwnode_reference_parse_int_props(struct device *dev,
> >
> > asd = v4l2_async_notifier_add_fwnode_subdev(notifier, fwnode,
> > sizeof(*asd));
> > + fwnode_handle_put(fwnode);
> > if (IS_ERR(asd)) {
> > /* not an error if asd already exists */
> > - if (PTR_ERR(asd) == -EEXIST) {
> > - fwnode_handle_put(fwnode);
> > + if (PTR_ERR(asd) == -EEXIST)
> > continue;
> > - }
> >
> > - goto error;
> > + return PTR_ERR(asd);
> > }
> > }
> >
> > return PTR_ERR(fwnode) == -ENOENT ? 0 : PTR_ERR(fwnode);
> > -
> > -error:
> > - fwnode_handle_put(fwnode);
> > - return PTR_ERR(fwnode);
> > }
> >
> > int v4l2_async_notifier_parse_fwnode_sensor_common(struct device *dev,
> > diff --git a/include/media/v4l2-async.h b/include/media/v4l2-async.h
> > index 1497bda66c3b..b9141ffa188a 100644
> > --- a/include/media/v4l2-async.h
> > +++ b/include/media/v4l2-async.h
> > @@ -175,8 +175,9 @@ int v4l2_async_notifier_add_subdev(struct v4l2_async_notifier *notifier,
> > * the driver's async sub-device struct, i.e. both
> > * begin at the same memory address.
> > *
> > - * Allocate a fwnode-matched asd of size asd_struct_size, and add it
> > - * to the notifiers @asd_list.
> > + * Allocate a fwnode-matched asd of size asd_struct_size, and add it to the
> > + * notifiers @asd_list. The function also gets a reference of the fwnode which
> > + * is released later at notifier cleanup time.
>
> I would add that, as a consequence, the caller need to put their local
> references as soon as they don't need them anymore (possibly just
> after calling this function).
I'd say that's redundant, as it's in line how refcounting generally works:
when you no longer need a reference, you put it.
>
> That apart
> Reviewed-by: Jacopo Mondi <jacopo+renesas@xxxxxxxxxx>
Thanks. :-)
--
Sakari Ailus
sakari.ailus@xxxxxxxxxxxxxxx
