Re: [RESEND PATCH 2/6] input: synaptics_usb: do not rely on input_dev->users

Dmitry Torokhov
2018-03-17T18:11:02Z

On Wed, Feb 28, 2018 at 02:37:59PM +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_dev->users || (synusb->flags & SYNUSB_IO_ALWAYS)) &&
> usb_submit_urb(synusb->urb, GFP_NOIO) < 0) {
> retval = -EIO;
> }
>
> The same URB will then be fail when resubmitted in synusb_open().
>
> Introduce synusb->is_open to keep track of the state instead.
>
> Signed-off-by: Marcus Folkesson <marcus.folkesson@gmail.com>

Applied, thank you.

> ---
> drivers/input/mouse/synaptics_usb.c | 9 +++++----
> 1 file changed, 5 insertions(+), 4 deletions(-)
>
> diff --git a/drivers/input/mouse/synaptics_usb.c b/drivers/input/mouse/synaptics_usb.c
> index 2c66913cf5a2..e2b726751220 100644
> --- a/drivers/input/mouse/synaptics_usb.c
> +++ b/drivers/input/mouse/synaptics_usb.c
> @@ -84,6 +84,7 @@ struct synusb {
>
> /* serialize access to open/suspend */
> struct mutex pm_mutex;
> + bool is_open;
>
> /* input device related data structures */
> struct input_dev *input;
> @@ -266,6 +267,7 @@ static int synusb_open(struct input_dev *dev)
> }
>
> synusb->intf->needs_remote_wakeup = 1;
> + synusb->is_open = 1;
>
> out:
> mutex_unlock(&synusb->pm_mutex);
> @@ -283,6 +285,7 @@ static void synusb_close(struct input_dev *dev)
> mutex_lock(&synusb->pm_mutex);
> usb_kill_urb(synusb->urb);
> synusb->intf->needs_remote_wakeup = 0;
> + synusb->is_open = 0;
> mutex_unlock(&synusb->pm_mutex);
>
> if (!autopm_error)
> @@ -485,12 +488,11 @@ static int synusb_suspend(struct usb_interface *intf, pm_message_t message)
> static int synusb_resume(struct usb_interface *intf)
> {
> struct synusb *synusb = usb_get_intfdata(intf);
> - struct input_dev *input_dev = synusb->input;
> int retval = 0;
>
> mutex_lock(&synusb->pm_mutex);
>
> - if ((input_dev->users || (synusb->flags & SYNUSB_IO_ALWAYS)) &&
> + if ((synusb->is_open || (synusb->flags & SYNUSB_IO_ALWAYS)) &&
> usb_submit_urb(synusb->urb, GFP_NOIO) < 0) {
> retval = -EIO;
> }
> @@ -513,10 +515,9 @@ static int synusb_pre_reset(struct usb_interface *intf)
> static int synusb_post_reset(struct usb_interface *intf)
> {
> struct synusb *synusb = usb_get_intfdata(intf);
> - struct input_dev *input_dev = synusb->input;
> int retval = 0;
>
> - if ((input_dev->users || (synusb->flags & SYNUSB_IO_ALWAYS)) &&
> + if ((synusb->is_open || (synusb->flags & SYNUSB_IO_ALWAYS)) &&
> usb_submit_urb(synusb->urb, GFP_NOIO) < 0) {
> retval = -EIO;
> }
> --
> 2.16.2
>

--
Dmitry