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References: <20190620150013.13462-1-narmstrong@baylibre.com> <20190620150013.13462-6-narmstrong@baylibre.com>
To:     Neil Armstrong <narmstrong@baylibre.com>, jbrunet@baylibre.com,
        khilman@baylibre.com
From:   Stephen Boyd <sboyd@kernel.org>
Subject: Re: [RFC/RFT 05/14] soc: amlogic: meson-clk-measure: protect measure with a mutex
Cc:     linux-arm-kernel@lists.infradead.org,
        linux-amlogic@lists.infradead.org, linux-kernel@vger.kernel.org,
        linux-clk@vger.kernel.org, martin.blumenstingl@googlemail.com,
        Neil Armstrong <narmstrong@baylibre.com>
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Date:   Tue, 25 Jun 2019 13:27:01 -0700
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Quoting Neil Armstrong (2019-06-20 08:00:04)
> In order to protect clock measuring when multiple process asks for
> a mesure, protect the main measure function with mutexes.
>=20
> Signed-off-by: Neil Armstrong <narmstrong@baylibre.com>
> ---
>  drivers/soc/amlogic/meson-clk-measure.c | 12 +++++++++++-
>  1 file changed, 11 insertions(+), 1 deletion(-)
>=20
> diff --git a/drivers/soc/amlogic/meson-clk-measure.c b/drivers/soc/amlogi=
c/meson-clk-measure.c
> index 19d4cbc93a17..c470e24f1dfa 100644
> --- a/drivers/soc/amlogic/meson-clk-measure.c
> +++ b/drivers/soc/amlogic/meson-clk-measure.c
> @@ -11,6 +11,8 @@
>  #include <linux/debugfs.h>
>  #include <linux/regmap.h>
> =20
> +static DEFINE_MUTEX(measure_lock);
> +
>  #define MSR_CLK_DUTY           0x0
>  #define MSR_CLK_REG0           0x4
>  #define MSR_CLK_REG1           0x8
> @@ -360,6 +362,10 @@ static int meson_measure_id(struct meson_msr_id *clk=
_msr_id,
>         unsigned int val;
>         int ret;
> =20
> +       ret =3D mutex_lock_interruptible(&measure_lock);

Why interruptible?

> +       if (ret)
> +               return ret;
> +
>         regmap_write(priv->regmap, MSR_CLK_REG0, 0);
> =20
>         /* Set measurement duration */