linux-kernel - RE: [PATCH v2 1/2] i2c: imx: use guard to take spinlock

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Message-ID:
 <PAXPR04MB8459E722812D2B11D57AA17F88812@PAXPR04MB8459.eurprd04.prod.outlook.com>
Date: Mon, 28 Apr 2025 00:55:48 +0000
From: Peng Fan <peng.fan@....com>
To: Troy Mitchell <troymitchell988@...il.com>, Oleksij Rempel
	<o.rempel@...gutronix.de>, Pengutronix Kernel Team <kernel@...gutronix.de>,
	Andi Shyti <andi.shyti@...nel.org>, Shawn Guo <shawnguo@...nel.org>, Sascha
 Hauer <s.hauer@...gutronix.de>, Fabio Estevam <festevam@...il.com>
CC: "linux-i2c@...r.kernel.org" <linux-i2c@...r.kernel.org>,
	"imx@...ts.linux.dev" <imx@...ts.linux.dev>,
	"linux-arm-kernel@...ts.infradead.org"
	<linux-arm-kernel@...ts.infradead.org>, "linux-kernel@...r.kernel.org"
	<linux-kernel@...r.kernel.org>, Yongchao Jia <jyc0019@...il.com>, Frank Li
	<frank.li@....com>
Subject: RE: [PATCH v2 1/2] i2c: imx: use guard to take spinlock

> Subject: [PATCH v2 1/2] i2c: imx: use guard to take spinlock
> 
> Use guard to automatically release the lock after going out of scope
> instead of calling it manually.
> 
> i2c_imx_slave_handle() can safely be entered with the lock held.
> 
> Refactored the i2c_imx_isr function so that i2c_imx_master_isr does
> not participate in the guard scope
> 
> So Using guard(spinlock_irqsave) simplifies the control flow by
> ensuring consistent and automatic unlock, which improves readability
> without affecting correctness.
> 
> Co-developed-by: Yongchao Jia <jyc0019@...il.com>
> Signed-off-by: Yongchao Jia <jyc0019@...il.com>
> Reviewed-by: Frank Li <Frank.Li@....com>
> Signed-off-by: Troy Mitchell <troymitchell988@...il.com>
> ---
>  drivers/i2c/busses/i2c-imx.c | 39 ++++++++++++++++++---------------------
>  1 file changed, 18 insertions(+), 21 deletions(-)
> 
> diff --git a/drivers/i2c/busses/i2c-imx.c b/drivers/i2c/busses/i2c-imx.c
> index 9e5d454d8318..a98bf01c5dde 100644
> --- a/drivers/i2c/busses/i2c-imx.c
> +++ b/drivers/i2c/busses/i2c-imx.c
> @@ -23,6 +23,7 @@
> 
>  #include <linux/acpi.h>
>  #include <linux/clk.h>
> +#include <linux/cleanup.h>
>  #include <linux/completion.h>
>  #include <linux/delay.h>
>  #include <linux/dma-mapping.h>
> @@ -891,13 +892,13 @@ static enum hrtimer_restart
> i2c_imx_slave_timeout(struct hrtimer *t)
>  	struct imx_i2c_struct *i2c_imx = container_of(t, struct
> imx_i2c_struct,
>  						      slave_timer);
>  	unsigned int ctl, status;
> -	unsigned long flags;
> 
> -	spin_lock_irqsave(&i2c_imx->slave_lock, flags);
> +	guard(spinlock_irqsave)(&i2c_imx->slave_lock);
> +
>  	status = imx_i2c_read_reg(i2c_imx, IMX_I2C_I2SR);
>  	ctl = imx_i2c_read_reg(i2c_imx, IMX_I2C_I2CR);
>  	i2c_imx_slave_handle(i2c_imx, status, ctl);
> -	spin_unlock_irqrestore(&i2c_imx->slave_lock, flags);
> +
>  	return HRTIMER_NORESTART;
>  }
> 
> @@ -1125,32 +1126,28 @@ static irqreturn_t i2c_imx_isr(int irq, void
> *dev_id)  {
>  	struct imx_i2c_struct *i2c_imx = dev_id;
>  	unsigned int ctl, status;
> -	unsigned long flags;
> 
> -	spin_lock_irqsave(&i2c_imx->slave_lock, flags);
> -	status = imx_i2c_read_reg(i2c_imx, IMX_I2C_I2SR);
> -	ctl = imx_i2c_read_reg(i2c_imx, IMX_I2C_I2CR);
> +	{
> +		guard(spinlock_irqsave)(&i2c_imx->slave_lock);

Use 
scoped_guard(spinlock_irqsave, & i2c_imx->slave_lock) {
 ...
}

Regards,
Peng