linux-kernel - Re: [PATCH] [v2] i2c: stm32f7: Fix runtime PM imbalance on error

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Message-ID: <20200601055634.GB17269@gnbcxd0016.gnb.st.com>
Date:   Mon, 1 Jun 2020 07:56:34 +0200
From:   Alain Volmat <alain.volmat@...com>
To:     Dinghao Liu <dinghao.liu@....edu.cn>
CC:     "kjlu@....edu" <kjlu@....edu>,
        Pierre Yves MORDRET <pierre-yves.mordret@...com>,
        Maxime Coquelin <mcoquelin.stm32@...il.com>,
        Alexandre TORGUE <alexandre.torgue@...com>,
        "linux-i2c@...r.kernel.org" <linux-i2c@...r.kernel.org>,
        "linux-stm32@...md-mailman.stormreply.com" 
        <linux-stm32@...md-mailman.stormreply.com>,
        "linux-arm-kernel@...ts.infradead.org" 
        <linux-arm-kernel@...ts.infradead.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH] [v2] i2c: stm32f7: Fix runtime PM imbalance on error

Hi,

Reviewed-by: Alain Volmat <alain.volmat@...com>

Thanks,
Alain

On Wed, May 27, 2020 at 01:38:53AM +0000, Dinghao Liu wrote:
> pm_runtime_get_sync() increments the runtime PM usage counter even
> the call returns an error code. Thus a pairing decrement is needed
> on the error handling path to keep the counter balanced.
> 
> Signed-off-by: Dinghao Liu <dinghao.liu@....edu.cn>
> ---
> 
> Changelog:
> 
> v2: - Use pm_runtime_put_noidle() instead of
>       pm_runtime_put_autosuspend(). Fix 5 more
>       similar cases within this dirver.
> ---
>  drivers/i2c/busses/i2c-stm32f7.c | 24 ++++++++++++++++++------
>  1 file changed, 18 insertions(+), 6 deletions(-)
> 
> diff --git a/drivers/i2c/busses/i2c-stm32f7.c b/drivers/i2c/busses/i2c-stm32f7.c
> index 330ffed011e0..822fd1f5b5ae 100644
> --- a/drivers/i2c/busses/i2c-stm32f7.c
> +++ b/drivers/i2c/busses/i2c-stm32f7.c
> @@ -1620,8 +1620,10 @@ static int stm32f7_i2c_xfer(struct i2c_adapter *i2c_adap,
>  	f7_msg->smbus = false;
>  
>  	ret = pm_runtime_get_sync(i2c_dev->dev);
> -	if (ret < 0)
> +	if (ret < 0) {
> +		pm_runtime_put_noidle(i2c_dev->dev);
>  		return ret;
> +	}
>  
>  	ret = stm32f7_i2c_wait_free_bus(i2c_dev);
>  	if (ret)
> @@ -1666,8 +1668,10 @@ static int stm32f7_i2c_smbus_xfer(struct i2c_adapter *adapter, u16 addr,
>  	f7_msg->smbus = true;
>  
>  	ret = pm_runtime_get_sync(dev);
> -	if (ret < 0)
> +	if (ret < 0) {
> +		pm_runtime_put_noidle(dev);
>  		return ret;
> +	}
>  
>  	ret = stm32f7_i2c_wait_free_bus(i2c_dev);
>  	if (ret)
> @@ -1767,8 +1771,10 @@ static int stm32f7_i2c_reg_slave(struct i2c_client *slave)
>  		return ret;
>  
>  	ret = pm_runtime_get_sync(dev);
> -	if (ret < 0)
> +	if (ret < 0) {
> +		pm_runtime_put_noidle(dev);
>  		return ret;
> +	}
>  
>  	if (!stm32f7_i2c_is_slave_registered(i2c_dev))
>  		stm32f7_i2c_enable_wakeup(i2c_dev, true);
> @@ -1837,8 +1843,10 @@ static int stm32f7_i2c_unreg_slave(struct i2c_client *slave)
>  	WARN_ON(!i2c_dev->slave[id]);
>  
>  	ret = pm_runtime_get_sync(i2c_dev->dev);
> -	if (ret < 0)
> +	if (ret < 0) {
> +		pm_runtime_put_noidle(i2c_dev->dev);
>  		return ret;
> +	}
>  
>  	if (id == 0) {
>  		mask = STM32F7_I2C_OAR1_OA1EN;
> @@ -2182,8 +2190,10 @@ static int stm32f7_i2c_regs_backup(struct stm32f7_i2c_dev *i2c_dev)
>  	struct stm32f7_i2c_regs *backup_regs = &i2c_dev->backup_regs;
>  
>  	ret = pm_runtime_get_sync(i2c_dev->dev);
> -	if (ret < 0)
> +	if (ret < 0) {
> +		pm_runtime_put_noidle(i2c_dev->dev);
>  		return ret;
> +	}
>  
>  	backup_regs->cr1 = readl_relaxed(i2c_dev->base + STM32F7_I2C_CR1);
>  	backup_regs->cr2 = readl_relaxed(i2c_dev->base + STM32F7_I2C_CR2);
> @@ -2204,8 +2214,10 @@ static int stm32f7_i2c_regs_restore(struct stm32f7_i2c_dev *i2c_dev)
>  	struct stm32f7_i2c_regs *backup_regs = &i2c_dev->backup_regs;
>  
>  	ret = pm_runtime_get_sync(i2c_dev->dev);
> -	if (ret < 0)
> +	if (ret < 0) {
> +		pm_runtime_put_noidle(i2c_dev->dev);
>  		return ret;
> +	}
>  
>  	cr1 = readl_relaxed(i2c_dev->base + STM32F7_I2C_CR1);
>  	if (cr1 & STM32F7_I2C_CR1_PE)
> -- 
> 2.17.1
>