Re: [PATCH] media: nxp: imx8-isi: remove kzalloc_objs

[Rosen Penev <rosenp@gmail.com>]

On Thu, Mar 19, 2026 at 3:09 PM Laurent Pinchart
<laurent.pinchart@ideasonboard.com> wrote:
>
> On Thu, Mar 05, 2026 at 08:45:36PM -0800, Rosen Penev wrote:
> > Use a flexible arraay member to combine allocations.
> >
> > It looks like pipes never gets freed anywhere. Meaning this effectively
> > fixes a memory leak.
> >
> > Signed-off-by: Rosen Penev <rosenp@gmail.com>
> > ---
> >  drivers/media/platform/nxp/imx8-isi/imx8-isi-core.c | 11 ++++-------
> >  drivers/media/platform/nxp/imx8-isi/imx8-isi-core.h |  3 ++-
> >  2 files changed, 6 insertions(+), 8 deletions(-)
> >
> > diff --git a/drivers/media/platform/nxp/imx8-isi/imx8-isi-core.c b/drivers/media/platform/nxp/imx8-isi/imx8-isi-core.c
> > index 16392420903a..657ffecc4d7e 100644
> > --- a/drivers/media/platform/nxp/imx8-isi/imx8-isi-core.c
> > +++ b/drivers/media/platform/nxp/imx8-isi/imx8-isi-core.c
> > @@ -459,25 +459,21 @@ static const struct dev_pm_ops mxc_isi_pm_ops = {
> >
> >  static int mxc_isi_probe(struct platform_device *pdev)
> >  {
> > +     const struct mxc_isi_plat_data *pdata;
> >       struct device *dev = &pdev->dev;
> >       struct mxc_isi_dev *isi;
> >       unsigned int dma_size;
> >       unsigned int i;
> >       int ret = 0;
> >
> > -     isi = devm_kzalloc(dev, sizeof(*isi), GFP_KERNEL);
> > +     pdata = of_device_get_match_data(dev);
> > +     isi = devm_kzalloc(dev, struct_size(isi, pipes, pdata->num_channels), GFP_KERNEL);
> >       if (!isi)
> >               return -ENOMEM;
> >
> >       isi->dev = dev;
> >       platform_set_drvdata(pdev, isi);
> >
> > -     isi->pdata = of_device_get_match_data(dev);
>
> I'd keep
>
>         isi->pdata = pdata;
>
> here and not below.
Sure
>
> > -
> > -     isi->pipes = kzalloc_objs(isi->pipes[0], isi->pdata->num_channels);
>
> Wouldn't it be simpler to just replace this with devm_kcalloc() ?
That would only make sense if pipes remained a pointer. A flex array
member allows combining allocations since it doesn't take up extra
space.

Technically kzalloc_flex is simpler but I assume a devm version of
that will be handled in another treewide commit.
>
>         isi->pipes = devm_kcalloc(dev, isi->pdata->num_channels,
>                                   sizeof(isi->pipes[0]), GFP_KERNEL);
>
> No other change would be needed.
With a flex array member, that's a compile time error, which I use as
a hint to complete the conversion.
>
> > -     if (!isi->pipes)
> > -             return -ENOMEM;
> > -
> >       isi->num_clks = devm_clk_bulk_get_all(dev, &isi->clks);
> >       if (isi->num_clks < 0)
> >               return dev_err_probe(dev, isi->num_clks, "Failed to get clocks\n");
> > @@ -487,6 +483,7 @@ static int mxc_isi_probe(struct platform_device *pdev)
> >               return dev_err_probe(dev, PTR_ERR(isi->regs),
> >                                    "Failed to get ISI register map\n");
> >
> > +     isi->pdata = pdata;
> >       if (isi->pdata->gasket_ops) {
> >               isi->gasket = syscon_regmap_lookup_by_phandle(dev->of_node,
> >                                                             "fsl,blk-ctrl");
> > diff --git a/drivers/media/platform/nxp/imx8-isi/imx8-isi-core.h b/drivers/media/platform/nxp/imx8-isi/imx8-isi-core.h
> > index 3cbd35305af0..99532efa4e41 100644
> > --- a/drivers/media/platform/nxp/imx8-isi/imx8-isi-core.h
> > +++ b/drivers/media/platform/nxp/imx8-isi/imx8-isi-core.h
> > @@ -286,7 +286,6 @@ struct mxc_isi_dev {
> >       struct regmap                   *gasket;
> >
> >       struct mxc_isi_crossbar         crossbar;
> > -     struct mxc_isi_pipe             *pipes;
> >       struct mxc_isi_m2m              m2m;
> >
> >       struct media_device             media_dev;
> > @@ -294,6 +293,8 @@ struct mxc_isi_dev {
> >       struct v4l2_async_notifier      notifier;
> >
> >       struct dentry                   *debugfs_root;
> > +
> > +     struct mxc_isi_pipe             pipes[];
> >  };
> >
> >  extern const struct mxc_gasket_ops mxc_imx8_gasket_ops;
>
> --
> Regards,
>
> Laurent Pinchart