Re: [PATCH v2] Input: synaptics_i2c - remove redundant spinlock

[Dmitry Torokhov]

On Sun, Feb 17, 2019 at 01:10:53AM -0500, thesven73@xxxxxxxxx wrote:
> From: Sven Van Asbroeck <TheSven73@xxxxxxxxx>
> 
> Remove a leftover spinlock.
> 
> This was required back when mod_delayed_work() did not exist,
> and had to be implemented with a cancel + queue. See
> commit e7c2f967445d ("workqueue: use mod_delayed_work() instead of
> __cancel + queue")
> 
> schedule_delayed_work() and mod_delayed_work() can now be used
> concurrently. So the spinlock is no longer needed.
> 
> Cc: Tejun Heo <tj@xxxxxxxxxx>
> Signed-off-by: Sven Van Asbroeck <TheSven73@xxxxxxxxx>

Applied, thank you.

> ---
> 
> v2: replace useless synaptics_i2c_reschedule_work() with
> 		mod_delayed_work().
> 
>  drivers/input/mouse/synaptics_i2c.c | 22 ++++------------------
>  1 file changed, 4 insertions(+), 18 deletions(-)
> 
> diff --git a/drivers/input/mouse/synaptics_i2c.c b/drivers/input/mouse/synaptics_i2c.c
> index 8538318d332c..fa304648d611 100644
> --- a/drivers/input/mouse/synaptics_i2c.c
> +++ b/drivers/input/mouse/synaptics_i2c.c
> @@ -219,7 +219,6 @@ struct synaptics_i2c {
>  	struct i2c_client	*client;
>  	struct input_dev	*input;
>  	struct delayed_work	dwork;
> -	spinlock_t		lock;
>  	int			no_data_count;
>  	int			no_decel_param;
>  	int			reduce_report_param;
> @@ -369,23 +368,11 @@ static bool synaptics_i2c_get_input(struct synaptics_i2c *touch)
>  	return xy_delta || gesture;
>  }
>  
> -static void synaptics_i2c_reschedule_work(struct synaptics_i2c *touch,
> -					  unsigned long delay)
> -{
> -	unsigned long flags;
> -
> -	spin_lock_irqsave(&touch->lock, flags);
> -
> -	mod_delayed_work(system_wq, &touch->dwork, delay);
> -
> -	spin_unlock_irqrestore(&touch->lock, flags);
> -}
> -
>  static irqreturn_t synaptics_i2c_irq(int irq, void *dev_id)
>  {
>  	struct synaptics_i2c *touch = dev_id;
>  
> -	synaptics_i2c_reschedule_work(touch, 0);
> +	mod_delayed_work(system_wq, &touch->dwork, 0);
>  
>  	return IRQ_HANDLED;
>  }
> @@ -461,7 +448,7 @@ static void synaptics_i2c_work_handler(struct work_struct *work)
>  	 * We poll the device once in THREAD_IRQ_SLEEP_SECS and
>  	 * if error is detected, we try to reset and reconfigure the touchpad.
>  	 */
> -	synaptics_i2c_reschedule_work(touch, delay);
> +	mod_delayed_work(system_wq, &touch->dwork, delay);
>  }
>  
>  static int synaptics_i2c_open(struct input_dev *input)
> @@ -474,7 +461,7 @@ static int synaptics_i2c_open(struct input_dev *input)
>  		return ret;
>  
>  	if (polling_req)
> -		synaptics_i2c_reschedule_work(touch,
> +		mod_delayed_work(system_wq, &touch->dwork,
>  				msecs_to_jiffies(NO_DATA_SLEEP_MSECS));
>  
>  	return 0;
> @@ -530,7 +517,6 @@ static struct synaptics_i2c *synaptics_i2c_touch_create(struct i2c_client *clien
>  	touch->scan_rate_param = scan_rate;
>  	set_scan_rate(touch, scan_rate);
>  	INIT_DELAYED_WORK(&touch->dwork, synaptics_i2c_work_handler);
> -	spin_lock_init(&touch->lock);
>  
>  	return touch;
>  }
> @@ -637,7 +623,7 @@ static int __maybe_unused synaptics_i2c_resume(struct device *dev)
>  	if (ret)
>  		return ret;
>  
> -	synaptics_i2c_reschedule_work(touch,
> +	mod_delayed_work(system_wq, &touch->dwork,
>  				msecs_to_jiffies(NO_DATA_SLEEP_MSECS));
>  
>  	return 0;
> -- 
> 2.17.1
> 

-- 
Dmitry