linux-kernel - Re: [PATCH] input: gpio-keys

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Message-ID: <CAMuHMdWdxveto0Vfv5jswk+PrkcvFgh2tA1xjDpd7i3Cds_FhQ@mail.gmail.com>
Date:   Mon, 4 Sep 2023 09:46:24 +0200
From:   Geert Uytterhoeven <geert@...ux-m68k.org>
To:     Lizhe <sensor1010@....com>
Cc:     dmitry.torokhov@...il.com, Jonathan.Cameron@...wei.com,
        soyer@....hu, linux-input@...r.kernel.org,
        linux-kernel@...r.kernel.org
Subject: Re: [PATCH] input: gpio-keys - use spin_lock()

Hi Lizhe,

Thanks for your patch!

On Sun, Sep 3, 2023 at 6:04 PM Lizhe <sensor1010@....com> wrote:
> Use the spin_lock() and spin_unlock() instead of spin_lock_irqsave()
> and spin_unlock_restore()

Please explain why...

> Signed-off-by: Lizhe <sensor1010@....com>

> --- a/drivers/input/keyboard/gpio_keys.c
> +++ b/drivers/input/keyboard/gpio_keys.c
> @@ -468,11 +468,10 @@ static irqreturn_t gpio_keys_irq_isr(int irq, void *dev_id)
>  {
>         struct gpio_button_data *bdata = dev_id;
>         struct input_dev *input = bdata->input;
> -       unsigned long flags;
>
>         BUG_ON(irq != bdata->irq);
>
> -       spin_lock_irqsave(&bdata->lock, flags);
> +       spin_lock(&bdata->lock);
>
>         if (!bdata->key_pressed) {
>                 if (bdata->button->wakeup)
> @@ -495,7 +494,7 @@ static irqreturn_t gpio_keys_irq_isr(int irq, void *dev_id)
>                               ms_to_ktime(bdata->release_delay),
>                               HRTIMER_MODE_REL_HARD);
>  out:
> -       spin_unlock_irqrestore(&bdata->lock, flags);
> +       spin_unlock(&bdata->lock);
>         return IRQ_HANDLED;
>  }

Are you sure this is safe, given the interrupt is requested with
devm_request_any_context_irq(), and thus the handler may be registered
using either request_irq() or request_threaded_irq()?

Gr{oetje,eeting}s,

                        Geert

-- 
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@...ux-m68k.org

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
                                -- Linus Torvalds