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SubjectRe: [PATCH] mux: core: Fix double get_device()
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On 2017-08-31 17:22, Hans de Goede wrote:
> class_find_device already does a get_device on the returned device.
> So the device returned by of_find_mux_chip_by_node is already referenced
> and we should not reference it again (and unref it on error).

Oops, yes that's right.

> Also rename of_find_mux_chip_by_node to of_get_mux_chip_by_node to
> make it clear that it returns a reference.

By that logic, you sign up for a lot of churn, these are but a few
examples:

s/of_find_device_by_node/of_get_device_by_node/
s/of_find_regulator_by_node/of_get_regulator_by_node/
s/of_find_spi_controller_by_node/of_get_spi_controller_by_node/
s/of_find_i2c_device_by_node/of_get_i2c_device_by_node/
s/of_find_i2c_adapter_by_node/of_get_i2c_adapter_by_node/

But there's already an of_get_i2c_adapter_by_node (that has slightly
different semantics) -> get ready for pushback.

So, I don't like the rename and would be much happier with a comment
above the function that the returned ref is supposed to be put away
when done.

Cheers,
Peter

> Signed-off-by: Hans de Goede <hdegoede@redhat.com>
> ---
> drivers/mux/core.c | 7 ++++---
> 1 file changed, 4 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/mux/core.c b/drivers/mux/core.c
> index 7aa656ac8fb5..8864cc745506 100644
> --- a/drivers/mux/core.c
> +++ b/drivers/mux/core.c
> @@ -433,7 +433,7 @@ static int of_dev_node_match(struct device *dev, const void *data)
> return dev->of_node == data;
> }
>
> -static struct mux_chip *of_find_mux_chip_by_node(struct device_node *np)
> +static struct mux_chip *of_get_mux_chip_by_node(struct device_node *np)
> {
> struct device *dev;
>
> @@ -471,7 +471,7 @@ static struct mux_control *of_mux_control_get(struct device *dev,
> return ERR_PTR(ret);
> }
>
> - mux_chip = of_find_mux_chip_by_node(args.np);
> + mux_chip = of_get_mux_chip_by_node(args.np);
> of_node_put(args.np);
> if (!mux_chip)
> return ERR_PTR(-EPROBE_DEFER);
> @@ -480,6 +480,7 @@ static struct mux_control *of_mux_control_get(struct device *dev,
> (!args.args_count && (mux_chip->controllers > 1))) {
> dev_err(dev, "%pOF: wrong #mux-control-cells for %pOF\n",
> np, args.np);
> + put_device(&mux_chip->dev);
> return ERR_PTR(-EINVAL);
> }
>
> @@ -490,10 +491,10 @@ static struct mux_control *of_mux_control_get(struct device *dev,
> if (controller >= mux_chip->controllers) {
> dev_err(dev, "%pOF: bad mux controller %u specified in %pOF\n",
> np, controller, args.np);
> + put_device(&mux_chip->dev);
> return ERR_PTR(-EINVAL);
> }
>
> - get_device(&mux_chip->dev);
> return &mux_chip->mux[controller];
> }
>
>

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