Re: [RESEND PATCH 6/6] input: usbtouchscreen: do not rely on input_dev->users

Dmitry Torokhov
2018-03-17T18:11:27Z

On Wed, Feb 28, 2018 at 02:38:03PM +0100, Marcus Folkesson wrote:
> If the device is unused and suspended, a call to open will cause the
> device to autoresume through the call to usb_autopm_get_interface().
>
> input_dev->users is already incremented by the input subsystem,
> therefore this expression will always be evaluated to true:
>
> if (input->users || usbtouch->type->irq_always)
> result = usb_submit_urb(usbtouch->irq, GFP_NOIO);
>
> The same URB will then be fail when resubmitted in usbtouch_open().
>
> Introduce usbtouch->is_open to keep track of the state instead.
>
> Signed-off-by: Marcus Folkesson <marcus.folkesson@gmail.com>

Applied, thank you.

> ---
> drivers/input/touchscreen/usbtouchscreen.c | 9 +++++----
> 1 file changed, 5 insertions(+), 4 deletions(-)
>
> diff --git a/drivers/input/touchscreen/usbtouchscreen.c b/drivers/input/touchscreen/usbtouchscreen.c
> index e964658203d8..0356ad792e40 100644
> --- a/drivers/input/touchscreen/usbtouchscreen.c
> +++ b/drivers/input/touchscreen/usbtouchscreen.c
> @@ -114,6 +114,7 @@ struct usbtouch_usb {
> struct input_dev *input;
> struct usbtouch_device_info *type;
> struct mutex pm_mutex; /* serialize access to open/suspend */
> + bool is_open;
> char name[128];
> char phys[64];
> void *priv;
> @@ -1466,6 +1467,7 @@ static int usbtouch_open(struct input_dev *input)
> }
>
> usbtouch->interface->needs_remote_wakeup = 1;
> + usbtouch->is_open = 1;
> out_put:
> mutex_unlock(&usbtouch->pm_mutex);
> usb_autopm_put_interface(usbtouch->interface);
> @@ -1481,6 +1483,7 @@ static void usbtouch_close(struct input_dev *input)
> mutex_lock(&usbtouch->pm_mutex);
> if (!usbtouch->type->irq_always)
> usb_kill_urb(usbtouch->irq);
> + usbtouch->is_open = 0;
> mutex_lock(&usbtouch->pm_mutex);
>
> r = usb_autopm_get_interface(usbtouch->interface);
> @@ -1502,11 +1505,10 @@ static int usbtouch_suspend
> static int usbtouch_resume(struct usb_interface *intf)
> {
> struct usbtouch_usb *usbtouch = usb_get_intfdata(intf);
> - struct input_dev *input = usbtouch->input;
> int result = 0;
>
> mutex_lock(&usbtouch->pm_mutex);
> - if (input->users || usbtouch->type->irq_always)
> + if (usbtouch->is_open || usbtouch->type->irq_always)
> result = usb_submit_urb(usbtouch->irq, GFP_NOIO);
> mutex_unlock(&usbtouch->pm_mutex);
>
> @@ -1516,7 +1518,6 @@ static int usbtouch_resume(struct usb_interface *intf)
> static int usbtouch_reset_resume(struct usb_interface *intf)
> {
> struct usbtouch_usb *usbtouch = usb_get_intfdata(intf);
> - struct input_dev *input = usbtouch->input;
> int err = 0;
>
> /* reinit the device */
> @@ -1532,7 +1533,7 @@ static int usbtouch_reset_resume(struct usb_interface *intf)
>
> /* restart IO if needed */
> mutex_lock(&usbtouch->pm_mutex);
> - if (input->users)
> + if (usbtouch->is_open)
> err = usb_submit_urb(usbtouch->irq, GFP_NOIO);
> mutex_unlock(&usbtouch->pm_mutex);
>
> --
> 2.16.2
>

--
Dmitry