Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) client-ip=2620:137:e000::1:20;
MIME-Version: 1.0
References: <20220824114927.79231-1-mmkurbanov@sberdevices.ru>
 <CAHp75VeQX_8niAu4uORW1YEfjxhLJFWsnm_JccECfAOAzAh32A@mail.gmail.com> <20220901224345.fy6xvbpdn4axtlks@Rockosov-MBP>
In-Reply-To: <20220901224345.fy6xvbpdn4axtlks@Rockosov-MBP>
From:   Andy Shevchenko <andy.shevchenko@gmail.com>
Date:   Fri, 2 Sep 2022 08:35:12 +0300
Message-ID: <CAHp75VeFT4coDG-fpZ2sErBxnhOpgU98Ctf+vcGcgLRTO6YMuQ@mail.gmail.com>
Subject: Re: [PATCH v1] leds: trigger: pattern: notify userpace if pattern finished
To:     Dmitry Rokosov <ddrokosov@sberdevices.ru>
Cc:     Martin Kurbanov <mmkurbanov@sberdevices.ru>,
        Pavel Machek <pavel@ucw.cz>,
        Raphael Teysseyre <rteysseyre@gmail.com>,
        Baolin Wang <baolin.wang@linaro.org>,
        Linux LED Subsystem <linux-leds@vger.kernel.org>,
        Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
        kernel <kernel@sberdevices.ru>
Content-Type: text/plain; charset="UTF-8"
Precedence: bulk

On Fri, Sep 2, 2022 at 1:43 AM Dmitry Rokosov <ddrokosov@sberdevices.ru> wrote:

...

> > > +static void pattern_trig_remove_pattern_ended(struct led_classdev *led_cdev)
> > > +{
> > > +       struct pattern_trig_data *data = led_get_trigger_data(led_cdev);
> > > +
> > > +       sysfs_put(data->pattern_ended);
> > > +       device_remove_file(led_cdev->dev, &dev_attr_pattern_ended);
> > > +}
> >
> > I'm wondering if you can always have a file and instead provide a
> > value there, so user space may use epoll() mechanism on that. It will
> > simplify your code here.
>
> Could you please explain what you mean? In the current implementation
> userspace can use epoll() already.

On the suddenly disappeared file?

-- 
With Best Regards,
Andy Shevchenko