Subject: Re: [PATCH v4 4/7] ACPI: button: Use input_device_enabled() helper

From: Dmitry Torokhov <[email-masked]>
Date: Wed, 24 Jun 2020 22:24:46 -0700

On Mon, Jun 08, 2020 at 01:22:08PM +0200, Andrzej Pietrasiewicz wrote:
> A new helper is available, so use it.
> 
> Signed-off-by: Andrzej Pietrasiewicz <[email-masked]>
> ---
>  drivers/acpi/button.c | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/acpi/button.c b/drivers/acpi/button.c
> index ff7ab291f678..4deb2b48d03c 100644
> --- a/drivers/acpi/button.c
> +++ b/drivers/acpi/button.c
> @@ -411,7 +411,7 @@ static void acpi_button_notify(struct acpi_device *device, u32 event)
>  		input = button->input;
>  		if (button->type == ACPI_BUTTON_TYPE_LID) {
>  			mutex_lock(&button->input->mutex);
> -			users = button->input->users;
> +			users = input_device_enabled(button->input);
>  			mutex_unlock(&button->input->mutex);
>  			if (users)

This chunk (pre-patch) is really wrong. 'users' value is obsolete and
can not be trusted the moment we unlocked the mutex. "if" needs to be
inside critical section.

>  				acpi_lid_update_state(device, true);
> @@ -460,7 +460,7 @@ static int acpi_button_resume(struct device *dev)
>  
>  	button->suspended = false;
>  	mutex_lock(&input->mutex);
> -	if (button->type == ACPI_BUTTON_TYPE_LID && input->users) {
> +	if (button->type == ACPI_BUTTON_TYPE_LID && input_device_enabled(input)) {
>  		button->last_state = !!acpi_lid_evaluate_state(device);
>  		button->last_time = ktime_get();
>  		acpi_lid_initialize_state(device);
> -- 
> 2.17.1
> 

Thanks.

-- 
Dmitry

_______________________________________________
linux-arm-kernel mailing list
[email-masked]
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel