[v5,1/3] uinput: Use monotonic times for uinput timestamps.
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Message ID 20171218051844.10193-2-deepa.kernel@gmail.com
State Under Review
Headers show

Commit Message

Deepa Dinamani Dec. 18, 2017, 5:18 a.m. UTC
struct timeval which is part of struct input_event to
maintain the event times is not y2038 safe.

Real time timestamps are also not ideal for input_event
as this time can go backwards as noted in the patch
a80b83b7b8 by John Stultz.

The patch switches the timestamps to use monotonic time
from realtime time. This is assuming no one is using
absolute times from these timestamps.

The structure to maintain input events will be changed
in a different patch.

Signed-off-by: Deepa Dinamani <deepa.kernel@gmail.com>
Acked-by: Peter Hutterer <peter.hutterer@who-t.net>
---
 drivers/input/misc/uinput.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

Comments

Dmitry Torokhov Jan. 2, 2018, 6:46 a.m. UTC | #1
On Sun, Dec 17, 2017 at 09:18:42PM -0800, Deepa Dinamani wrote:
> struct timeval which is part of struct input_event to
> maintain the event times is not y2038 safe.
> 
> Real time timestamps are also not ideal for input_event
> as this time can go backwards as noted in the patch
> a80b83b7b8 by John Stultz.
> 
> The patch switches the timestamps to use monotonic time
> from realtime time. This is assuming no one is using
> absolute times from these timestamps.
> 
> The structure to maintain input events will be changed
> in a different patch.
> 
> Signed-off-by: Deepa Dinamani <deepa.kernel@gmail.com>
> Acked-by: Peter Hutterer <peter.hutterer@who-t.net>

Applied, thank you.

> ---
>  drivers/input/misc/uinput.c | 5 ++++-
>  1 file changed, 4 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/input/misc/uinput.c b/drivers/input/misc/uinput.c
> index 91df0df15e68..9251765645d1 100644
> --- a/drivers/input/misc/uinput.c
> +++ b/drivers/input/misc/uinput.c
> @@ -84,11 +84,14 @@ static int uinput_dev_event(struct input_dev *dev,
>  			    unsigned int type, unsigned int code, int value)
>  {
>  	struct uinput_device	*udev = input_get_drvdata(dev);
> +	struct timespec64	ts;
>  
>  	udev->buff[udev->head].type = type;
>  	udev->buff[udev->head].code = code;
>  	udev->buff[udev->head].value = value;
> -	do_gettimeofday(&udev->buff[udev->head].time);
> +	ktime_get_ts64(&ts);
> +	udev->buff[udev->head].time.tv_sec = ts.tv_sec;
> +	udev->buff[udev->head].time.tv_usec = ts.tv_nsec / NSEC_PER_USEC;
>  	udev->head = (udev->head + 1) % UINPUT_BUFFER_SIZE;
>  
>  	wake_up_interruptible(&udev->waitq);
> -- 
> 2.14.1
>

Patch
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diff --git a/drivers/input/misc/uinput.c b/drivers/input/misc/uinput.c
index 91df0df15e68..9251765645d1 100644
--- a/drivers/input/misc/uinput.c
+++ b/drivers/input/misc/uinput.c
@@ -84,11 +84,14 @@  static int uinput_dev_event(struct input_dev *dev,
 			    unsigned int type, unsigned int code, int value)
 {
 	struct uinput_device	*udev = input_get_drvdata(dev);
+	struct timespec64	ts;
 
 	udev->buff[udev->head].type = type;
 	udev->buff[udev->head].code = code;
 	udev->buff[udev->head].value = value;
-	do_gettimeofday(&udev->buff[udev->head].time);
+	ktime_get_ts64(&ts);
+	udev->buff[udev->head].time.tv_sec = ts.tv_sec;
+	udev->buff[udev->head].time.tv_usec = ts.tv_nsec / NSEC_PER_USEC;
 	udev->head = (udev->head + 1) % UINPUT_BUFFER_SIZE;
 
 	wake_up_interruptible(&udev->waitq);