答复: [PATCH] Input: omap-keypad: Fix error goto and handling in omap4_keypad_probe

[zhangqilong <zhangqilong3@huawei.com>]

> Hi Zhang,
> 
> On Thu, Nov 19, 2020 at 03:01:19PM +0800, Zhang Qilong wrote:
> > In omap4_keypad_probe, the patch fix several bugs.
> >
> >   1) pm_runtime_get_sync will increment pm usage counter even it
> >      failed. Forgetting to pm_runtime_put_noidle will result in
> >      reference leak.
> >
> >   2) In err_unmap, forget to disable runtime of device,
> >      pm_runtime_enable will increase power disable depth. Thus a
> >      pairing decrement is needed on the error handling path to keep
> >      it balanced.
> >
> >   3) In err_pm_disable, it will call pm_runtime_put_sync twice not
> >      one time.
> >
> > And we add the pm_runtime_put_noidle when pm_runtime_get_sync failed
> > for 1). Move pm_runtime_disable to the err_unmap branch for 2). Move
> > the input_register_device ahead for 3).
> >
> > Fixes: f77621cc640a7 ("Input: omap-keypad - dynamically handle
> > register offsets")
> > Fixes: 5ad567ffbaf20 ("Input: Input: omap4-keypad - wire up runtime PM
> > handling")
> > Signed-off-by: Zhang Qilong <zhangqilong3@huawei.com>
> > ---
> >  drivers/input/keyboard/omap4-keypad.c | 13 +++++++------
> >  1 file changed, 7 insertions(+), 6 deletions(-)
> >
> > diff --git a/drivers/input/keyboard/omap4-keypad.c
> > b/drivers/input/keyboard/omap4-keypad.c
> > index d6c924032aaa..17abc8434af5 100644
> > --- a/drivers/input/keyboard/omap4-keypad.c
> > +++ b/drivers/input/keyboard/omap4-keypad.c
> > @@ -277,6 +277,7 @@ static int omap4_keypad_probe(struct
> platform_device *pdev)
> >  	pm_runtime_enable(&pdev->dev);
> >  	error = pm_runtime_get_sync(&pdev->dev);
> >  	if (error) {
> > +		pm_runtime_put_noidle(&pdev->dev);
> >  		dev_err(&pdev->dev, "pm_runtime_get_sync() failed\n");
> >  		goto err_unmap;
> >  	}
> > @@ -349,20 +350,19 @@ static int omap4_keypad_probe(struct
> platform_device *pdev)
> >  		goto err_free_keymap;
> >  	}
> >
> > -	device_init_wakeup(&pdev->dev, true);
> > -	pm_runtime_put_sync(&pdev->dev);
> > -
> >  	error = input_register_device(keypad_data->input);
> >  	if (error < 0) {
> >  		dev_err(&pdev->dev, "failed to register input device\n");
> > -		goto err_pm_disable;
> > +		goto err_free_irq;
> >  	}
> >
> > +	device_init_wakeup(&pdev->dev, true);
> > +	pm_runtime_put_sync(&pdev->dev);
> > +
> 
> I think your patch is technically correct, but I wonder if we should limit area of
> where we have device's clocks enabled to only where we need it. I.e.
> something like this:
> 
> diff --git a/drivers/input/keyboard/omap4-keypad.c
> b/drivers/input/keyboard/omap4-keypad.c
> index d6c924032aaa..4ca754e95978 100644
> --- a/drivers/input/keyboard/omap4-keypad.c
> +++ b/drivers/input/keyboard/omap4-keypad.c
> @@ -186,12 +186,8 @@ static int omap4_keypad_open(struct input_dev
> *input)
>  	return 0;
>  }
> 
> -static void omap4_keypad_close(struct input_dev *input)
> +static void omap4_keypad_stop(struct omap4_keypad *keypad_data)
>  {
> -	struct omap4_keypad *keypad_data = input_get_drvdata(input);
> -
> -	disable_irq(keypad_data->irq);
> -
>  	/* Disable interrupts and wake-up events */
>  	kbd_write_irqreg(keypad_data, OMAP4_KBD_IRQENABLE,
>  			 OMAP4_VAL_IRQDISABLE);
> @@ -200,7 +196,14 @@ static void omap4_keypad_close(struct input_dev
> *input)
>  	/* clear pending interrupts */
>  	kbd_write_irqreg(keypad_data, OMAP4_KBD_IRQSTATUS,
>  			 kbd_read_irqreg(keypad_data, OMAP4_KBD_IRQSTATUS));
> +}
> 
> +static void omap4_keypad_close(struct input_dev *input) {
> +	struct omap4_keypad *keypad_data = input_get_drvdata(input);
> +
> +	disable_irq(keypad_data->irq);
> +	omap4_keypad_stop(keypad_data);
>  	enable_irq(keypad_data->irq);
> 
>  	pm_runtime_put_sync(input->dev.parent);
> @@ -223,13 +226,37 @@ static int omap4_keypad_parse_dt(struct device
> *dev,
>  	return 0;
>  }
> 
> +static int omap4_keypad_check_revision(struct device *dev,
> +				       struct omap4_keypad *keypad_data) {
> +	unsigned int rev;
> +
> +	rev = __raw_readl(keypad_data->base + OMAP4_KBD_REVISION);
> +	rev &= 0x03 << 30;
> +	rev >>= 30;
> +	switch (rev) {
> +	case KBD_REVISION_OMAP4:
> +		keypad_data->reg_offset = 0x00;
> +		keypad_data->irqreg_offset = 0x00;
> +		break;
> +	case KBD_REVISION_OMAP5:
> +		keypad_data->reg_offset = 0x10;
> +		keypad_data->irqreg_offset = 0x0c;
> +		break;
> +	default:
> +		dev_err(dev, "Keypad reports unsupported revision %d", rev);
> +		return -EINVAL;
> +	}
> +
> +	return 0;
> +}
> +
>  static int omap4_keypad_probe(struct platform_device *pdev)  {
>  	struct omap4_keypad *keypad_data;
>  	struct input_dev *input_dev;
>  	struct resource *res;
>  	unsigned int max_keys;
> -	int rev;
>  	int irq;
>  	int error;
> 
> @@ -269,41 +296,30 @@ static int omap4_keypad_probe(struct
> platform_device *pdev)
>  		goto err_release_mem;
>  	}
> 
> +	pm_runtime_enable(&pdev->dev);
> 
>  	/*
>  	 * Enable clocks for the keypad module so that we can read
>  	 * revision register.
>  	 */
> -	pm_runtime_enable(&pdev->dev);
>  	error = pm_runtime_get_sync(&pdev->dev);
>  	if (error) {
>  		dev_err(&pdev->dev, "pm_runtime_get_sync() failed\n");
> -		goto err_unmap;
> -	}
> -	rev = __raw_readl(keypad_data->base + OMAP4_KBD_REVISION);
> -	rev &= 0x03 << 30;
> -	rev >>= 30;
> -	switch (rev) {
> -	case KBD_REVISION_OMAP4:
> -		keypad_data->reg_offset = 0x00;
> -		keypad_data->irqreg_offset = 0x00;
> -		break;
> -	case KBD_REVISION_OMAP5:
> -		keypad_data->reg_offset = 0x10;
> -		keypad_data->irqreg_offset = 0x0c;
> -		break;
> -	default:
> -		dev_err(&pdev->dev,
> -			"Keypad reports unsupported revision %d", rev);
> -		error = -EINVAL;
> -		goto err_pm_put_sync;
> +		pm_runtime_put_noidle(&pdev->dev);

I think it's OK, that is more clearly, here it should goto err_pm_disable ?

Thanks,
Zhang

> +	} else {
> +		error = omap4_keypad_check_revision(&pdev->dev, keypad_data);
> +		if (!error) {
> +			/* Ensure device does not raise interrupts */
> +			omap4_keypad_stop(keypad_data);
> +		}
> +		pm_runtime_put_sync(&pdev->dev);
>  	}
> 
>  	/* input device allocation */
>  	keypad_data->input = input_dev = input_allocate_device();
>  	if (!input_dev) {
>  		error = -ENOMEM;
> -		goto err_pm_put_sync;
> +		goto err_pm_disable;
>  	}
> 
>  	input_dev->name = pdev->name;
> @@ -349,28 +365,25 @@ static int omap4_keypad_probe(struct
> platform_device *pdev)
>  		goto err_free_keymap;
>  	}
> 
> -	device_init_wakeup(&pdev->dev, true);
> -	pm_runtime_put_sync(&pdev->dev);
> -
>  	error = input_register_device(keypad_data->input);
>  	if (error < 0) {
>  		dev_err(&pdev->dev, "failed to register input device\n");
> -		goto err_pm_disable;
> +		goto err_free_irq;
>  	}
> 
> +	device_init_wakeup(&pdev->dev, true);
>  	platform_set_drvdata(pdev, keypad_data);
> +
>  	return 0;
> 
> -err_pm_disable:
> -	pm_runtime_disable(&pdev->dev);
> +err_free_irq:
>  	free_irq(keypad_data->irq, keypad_data);
>  err_free_keymap:
>  	kfree(keypad_data->keymap);
>  err_free_input:
>  	input_free_device(input_dev);
> -err_pm_put_sync:
> -	pm_runtime_put_sync(&pdev->dev);
> -err_unmap:
> +err_pm_disable:
> +	pm_runtime_disable(&pdev->dev);
>  	iounmap(keypad_data->base);
>  err_release_mem:
>  	release_mem_region(res->start, resource_size(res));
> 
> >  	platform_set_drvdata(pdev, keypad_data);
> >  	return 0;
> >
> > -err_pm_disable:
> > -	pm_runtime_disable(&pdev->dev);
> > +err_free_irq:
> >  	free_irq(keypad_data->irq, keypad_data);
> >  err_free_keymap:
> >  	kfree(keypad_data->keymap);
> > @@ -371,6 +371,7 @@ static int omap4_keypad_probe(struct
> > platform_device *pdev)
> >  err_pm_put_sync:
> >  	pm_runtime_put_sync(&pdev->dev);
> >  err_unmap:
> > +	pm_runtime_disable(&pdev->dev);
> >  	iounmap(keypad_data->base);
> >  err_release_mem:
> >  	release_mem_region(res->start, resource_size(res));
> > --
> > 2.25.4
> >
> 
> Thanks.
> 
> --
> Dmitry