On Thu, Mar 19, 2026 at 06:06:07PM -0700, Rosen Penev wrote:
> On Thu, Mar 19, 2026 at 5:57 PM Laurent Pinchart wrote:
> > On Thu, Mar 19, 2026 at 05:11:22PM -0700, Rosen Penev wrote:
> > > On Thu, Mar 19, 2026 at 3:09 PM Laurent Pinchart 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 <[email protected]>
> > > > > ---
> > > > > 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.
> >
> > Yes, I understand that. My point was that with devm_kzalloc() here you
> > won't need to change the mxc_isi_dev structure. The leak fix will be a
> > one-liner patch.
>
> Leak fix is not the point of the patch to be fair.
If I understand correctly, your main point is to combine two
allocations.
I don't liek this much in this specific case. mxc_isi_dev is the
top-level driver structure. As part of all the data it stores, there
is a pointer to a dynamically-allocated array, and the current
implementation happens to not have any other dynamically allocated
member. That is however not an intrinsic property of the mxc_isi_dev
structure. Treating pipes as a flex arrat within mxc_isi_dev won't scale
to a second similar member, and there's no reason to treat pipes in a
special way. I prefer fixing the leak and avoiding the flex array.
> > > 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
