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From: Arnd Bergmann <arnd@kernel.org>
To: Grygorii Strashko <grygorii.strashko@ti.com>
Cc: "Song Bao Hua (Barry Song)" <song.bao.hua@hisilicon.com>,
	Andy Shevchenko <andy.shevchenko@gmail.com>,
	luojiaxing <luojiaxing@huawei.com>,
	Linus Walleij <linus.walleij@linaro.org>,
	Santosh Shilimkar <ssantosh@kernel.org>,
	Kevin Hilman <khilman@kernel.org>,
	"open list:GPIO SUBSYSTEM" <linux-gpio@vger.kernel.org>,
	"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
	"linuxarm@openeuler.org" <linuxarm@openeuler.org>
Subject: Re: [Linuxarm] Re: [PATCH for next v1 1/2] gpio: omap: Replace raw_spin_lock_irqsave with raw_spin_lock in omap_gpio_irq_handler()
Date: Fri, 12 Feb 2021 21:23:23 +0100	[thread overview]
Message-ID: <CAK8P3a0JEhhw4vB=YgUJj5_ywds=sVuzPd4Zf0iiRwX4Mgsk3g@mail.gmail.com> (raw)
In-Reply-To: <33720e72-a438-8ffe-1b5f-38756738ad9b@ti.com>

On Fri, Feb 12, 2021 at 12:53 PM Grygorii Strashko
<grygorii.strashko@ti.com> wrote:
>
> The worst RT case I can imagine is when gpio API is still called from hard IRQ context by some
> other device driver - some toggling for example.
> Note. RT or "threadirqs" does not mean gpiochip become sleepable.
>
> In this case:
>   threaded handler
>     raw_spin_lock
>         IRQ from other device
>            hard_irq handler
>              gpiod_x()
>                 raw_spin_lock_irqsave() -- oops
>

Good point, I had missed the fact that drivers can call gpio functions from
hardirq context when I replied earlier, gpio is clearly special here.

          Arnd

  parent reply	other threads:[~2021-02-12 20:24 UTC|newest]

Thread overview: 30+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-02-08  8:56 [PATCH for next v1 0/2] gpio: few clean up patches to replace spin_lock_irqsave with spin_lock Luo Jiaxing
2021-02-08  8:56 ` [PATCH for next v1 1/2] gpio: omap: Replace raw_spin_lock_irqsave with raw_spin_lock in omap_gpio_irq_handler() Luo Jiaxing
2021-02-11 18:14   ` Grygorii Strashko
2021-02-11 19:39     ` Arnd Bergmann
2021-02-11 20:16       ` Grygorii Strashko
2021-02-12  5:05         ` [Linuxarm] " Song Bao Hua (Barry Song)
2021-02-12  9:45           ` Arnd Bergmann
2021-02-12 10:25             ` Song Bao Hua (Barry Song)
2021-02-12 10:27             ` Grygorii Strashko
2021-02-12 10:42               ` Song Bao Hua (Barry Song)
2021-02-12 10:57                 ` Andy Shevchenko
2021-02-12 11:29                   ` Song Bao Hua (Barry Song)
2021-02-12 11:53                     ` Grygorii Strashko
2021-02-12 13:12                       ` Song Bao Hua (Barry Song)
2021-02-12 14:08                         ` Grygorii Strashko
2021-02-12 20:06                           ` Song Bao Hua (Barry Song)
2021-02-12 20:23                       ` Arnd Bergmann [this message]
2021-02-12 20:49                         ` Song Bao Hua (Barry Song)
2021-02-12 10:59                 ` Arnd Bergmann
2021-02-12 11:35                   ` Andy Shevchenko
2021-02-08  9:11 ` [Linuxarm] [PATCH for next v1 0/2] gpio: few clean up patches to replace spin_lock_irqsave with spin_lock luojiaxing
2021-02-08 13:28   ` Andy Shevchenko
2021-02-09  9:24     ` luojiaxing
2021-02-09  9:42       ` Andy Shevchenko
2021-02-10  3:43         ` luojiaxing
2021-02-10 10:50           ` Andy Shevchenko
2021-02-10 11:50             ` [Linuxarm] " Song Bao Hua (Barry Song)
2021-02-10 14:56               ` Andy Shevchenko
2021-02-10 20:42                 ` Song Bao Hua (Barry Song)
2021-02-11  9:58                   ` Andy Shevchenko

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