Re: [PATCH] gpiolib: fix line event timestamps for nested irqs

[Linus Walleij]

On Fri, Jan 4, 2019 at 11:32 AM Bartosz Golaszewski <brgl@xxxxxxxx> wrote:

> From: Bartosz Golaszewski <bgolaszewski@xxxxxxxxxxxx>
>
> Nested interrupts run inside the calling thread's context and the top
> half handler is never called which means that we never read the
> timestamp.
>
> This issue came up when trying to read line events from a gpiochip
> using regmap_irq_chip for interrupts.
>
> Fix it by reading the timestamp from the irq thread function if it's
> still 0 by the time the second handler is called.
>
> Signed-off-by: Bartosz Golaszewski <bgolaszewski@xxxxxxxxxxxx>

Oh that's right. Should this not have Fixes: and Cc: stable?

> +       /*
> +        * We may be running from a nested threaded interrupt in which case
> +        * we didn't get the timestamp from lineevent_irq_handler().
> +        */
> +       if (!le->timestamp)
> +               le->timestamp = ktime_get_real_ns();
> +
>         ge.timestamp = le->timestamp;

I would merge these:

if (!le->timestamp)
    ge.timestamp = ktime_get_real_ns();
else
    ge.timestamp = le->timestamp;

Yours,
Linus Walleij