linux-kernel - Re: [PATCH v2 2/4] pinctrl: rockchip: convert to raw spinlock

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Message-ID: <20170315180137.GB682@jcartwri.amer.corp.natinst.com>
Date:   Wed, 15 Mar 2017 13:01:37 -0500
From:   Julia Cartwright <julia@...com>
To:     John Keeping <john@...anate.com>
CC:     Heiko Stuebner <heiko@...ech.de>,
        Linus Walleij <linus.walleij@...aro.org>,
        <linux-gpio@...r.kernel.org>,
        <linux-arm-kernel@...ts.infradead.org>,
        <linux-rockchip@...ts.infradead.org>,
        <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH v2 2/4] pinctrl: rockchip: convert to raw spinlock

Hello John-

On Wed, Mar 15, 2017 at 05:46:52PM +0000, John Keeping wrote:
> This lock is used from rockchip_irq_set_type() which is part of the
> irq_chip implementation and thus must use raw_spinlock_t as documented
> in Documentation/gpio/driver.txt.
> 
> Signed-off-by: John Keeping <john@...anate.com>
> Reviewed-by: Heiko Stuebner <heiko@...ech.de>
> Tested-by: Heiko Stuebner <heiko@...ech.de>
> ---
> v2: unchanged
> ---
>  drivers/pinctrl/pinctrl-rockchip.c | 30 +++++++++++++++---------------
>  1 file changed, 15 insertions(+), 15 deletions(-)
> 
> diff --git a/drivers/pinctrl/pinctrl-rockchip.c b/drivers/pinctrl/pinctrl-rockchip.c
> index 128c383ea7ba..8c1cae6d78d7 100644
> --- a/drivers/pinctrl/pinctrl-rockchip.c
> +++ b/drivers/pinctrl/pinctrl-rockchip.c
> @@ -163,7 +163,7 @@ struct rockchip_pin_bank {
>  	struct irq_domain		*domain;
>  	struct gpio_chip		gpio_chip;
>  	struct pinctrl_gpio_range	grange;
> -	spinlock_t			slock;
> +	raw_spinlock_t			slock;
>  	u32				toggle_edge_mode;
>  };
>  
> @@ -1295,14 +1295,14 @@ static int rockchip_set_pull(struct rockchip_pin_bank *bank,
>  
>  	switch (ctrl->type) {
>  	case RK2928:
> -		spin_lock_irqsave(&bank->slock, flags);
> +		raw_spin_lock_irqsave(&bank->slock, flags);
>  
>  		data = BIT(bit + 16);
>  		if (pull == PIN_CONFIG_BIAS_DISABLE)
>  			data |= BIT(bit);

This should be lifted out from under the lock.

>  		ret = regmap_write(regmap, reg, data);

How is this legal?  The regmap_write() here is going to end up acquiring
the regmap mutex.

   Julia

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