Re: [PATCH linux-next] media:cdns-csi2tx: replace of_node_put() with __free

[R Sundar]

On 30/04/24 22:53, Julia Lawall wrote:
> On Tue, 30 Apr 2024, R Sundar wrote:
>
> > On 30/04/24 00:10, Christophe JAILLET wrote:
> > > Le 29/04/2024 à 19:15, R Sundar a écrit :
> > > > Use the new cleanup magic to replace of_node_put() with
> > > > __free(device_node) marking to auto release when they get out of scope.
> > > >
> > > > Suggested-by: Julia Lawall <julia.lawall@xxxxxxxx>
> > > > Signed-off-by: R Sundar <prosunofficial@xxxxxxxxx>
> > > > ---
> > > >    drivers/media/platform/cadence/cdns-csi2tx.c | 19 +++++++------------
> > > >    1 file changed, 7 insertions(+), 12 deletions(-)
> > > >
> > > > diff --git a/drivers/media/platform/cadence/cdns-csi2tx.c
> > > > b/drivers/media/platform/cadence/cdns-csi2tx.c
> > > > index 3d98f91f1bee..88aed2f299fd 100644
> > > > --- a/drivers/media/platform/cadence/cdns-csi2tx.c
> > > > +++ b/drivers/media/platform/cadence/cdns-csi2tx.c
> > > > @@ -496,48 +496,43 @@ static int csi2tx_get_resources(struct csi2tx_priv
> > > > *csi2tx,
> > > >    static int csi2tx_check_lanes(struct csi2tx_priv *csi2tx)
> > > >    {
> > > >        struct v4l2_fwnode_endpoint v4l2_ep = { .bus_type = 0 };
> > > > -    struct device_node *ep;
> > > >        int ret, i;
> > > > -
> > > > -    ep = of_graph_get_endpoint_by_regs(csi2tx->dev->of_node, 0, 0);
> > > > +    struct device_node *ep __free(device_node) =
> > > > +        of_graph_get_endpoint_by_regs(csi2tx->dev->of_node, 0, 0);
> > > > +
> > > >        if (!ep)
> > > >            return -EINVAL;
> > > >        ret = v4l2_fwnode_endpoint_parse(of_fwnode_handle(ep), &v4l2_ep);
> > > >        if (ret) {
> > > >            dev_err(csi2tx->dev, "Could not parse v4l2 endpoint\n");
> > > > -        goto out;
> > > > +        return ret;
> > > >        }
> > > >        if (v4l2_ep.bus_type != V4L2_MBUS_CSI2_DPHY) {
> > > >            dev_err(csi2tx->dev, "Unsupported media bus type: 0x%x\n",
> > > >                v4l2_ep.bus_type);
> > > > -        ret = -EINVAL;
> > > > -        goto out;
> > > > +        return -EINVAL;
> > > >        }
> > > >        csi2tx->num_lanes = v4l2_ep.bus.mipi_csi2.num_data_lanes;
> > > >        if (csi2tx->num_lanes > csi2tx->max_lanes) {
> > > >            dev_err(csi2tx->dev,
> > > >                "Current configuration uses more lanes than supported\n");
> > > > -        ret = -EINVAL;
> > > > -        goto out;
> > > > +        return -EINVAL;
> > > >        }
> > > >        for (i = 0; i < csi2tx->num_lanes; i++) {
> > > >            if (v4l2_ep.bus.mipi_csi2.data_lanes[i] < 1) {
> > > >                dev_err(csi2tx->dev, "Invalid lane[%d] number: %u\n",
> > > >                    i, v4l2_ep.bus.mipi_csi2.data_lanes[i]);
> > > > -            ret = -EINVAL;
> > > > -            goto out;
> > > > +            return -EINVAL;
> > > >            }
> > > >        }
> > > >        memcpy(csi2tx->lanes, v4l2_ep.bus.mipi_csi2.data_lanes,
> > > >               sizeof(csi2tx->lanes));
> > > > -out:
> > > > -    of_node_put(ep);
> > > >        return ret;
> > >
> > > Hi,
> > >
> > > Nit: return 0; ?
> > >
> > > CJ
> > >
> > > >    }
> > Hi,
> >
> > In success case, ret variable value also will be zero, else for non-zero ret
> > value it will return from v4l2_fwnode_endpoint_parse()'s error case handling
> > block.
>
> Indeed, but it seems that the return ret at the end of the function always
> returns 0?  If that is the case, return 0 would be better, as one can see
> that that code is only reached in the success case.
>
> julia

Hi Julia,

Noted.

@CJ, Thanks for comments.  Understood the point of Nit.

Will update the changes.

Thanks,
Sundar