Re: [PATCH] iio: pressure: rohm-bm1390: notify trigger on all error paths

[Andy Shevchenko]

On Mon, May 18, 2026 at 08:21:17AM +0300, Matti Vaittinen wrote:
> On 17/05/2026 20:12, David Lechner wrote:
> > On 5/17/26 11:08 AM, Stepan Ionichev wrote:

...

> Maybe it would be better to do something like:
> 
> void iio_trigger_poll_nested(struct iio_trigger *trig)
> {
>         int i;
> 
>         if (!atomic_read(&trig->use_count)) {
>                 atomic_set(&trig->use_count,
> CONFIG_IIO_CONSUMERS_PER_TRIGGER);

Just in case somebody is going to do that, avoid doing atomic_read() followed
by atomic_set(). This is typical TOCTOU issue. This should be something like
atomic_xchg() or atomic_add_return() or something like this in a single atomic
operation.

>                 for (i = 0; i < CONFIG_IIO_CONSUMERS_PER_TRIGGER; i++) {
>                         if (trig->subirqs[i].enabled)
>                                 handle_nested_irq(trig->subirq_base + i);
>                         else
>                                 iio_trigger_notify_done(trig);
>                 }
> 		atomic_set(&trig->use_count, 0); /* Clear the use_count if drivers didn't
> */
>         }
> }
> 
> to prevent this class of problems once and for all. But yeah, wiser minds
> have designed this - so let's hear some other opinions as well :)


-- 
With Best Regards,
Andy Shevchenko