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From: Linus Walleij <linus.walleij@linaro.org>
To: Grygorii Strashko <grygorii.strashko@ti.com>
Cc: Russell King <rmk@arm.linux.org.uk>,
	Tony Lindgren <tony@atomide.com>,
	Bartosz Golaszewski <bgolaszewski@baylibre.com>,
	Linux-OMAP <linux-omap@vger.kernel.org>,
	"open list:GPIO SUBSYSTEM" <linux-gpio@vger.kernel.org>,
	"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
	Santosh Shilimkar <ssantosh@kernel.org>,
	Russell King <rmk+kernel@armlinux.org.uk>
Subject: Re: [PATCH-next 07/20] gpio: gpio-omap: simplify omap_gpio_get_direction()
Date: Wed, 12 Jun 2019 10:47:23 +0200	[thread overview]
Message-ID: <CACRpkdYaropisZADA61LF_0aUmWzi44c7pQbEUV92r06Qu3m_w@mail.gmail.com> (raw)
In-Reply-To: <20190610171103.30903-8-grygorii.strashko@ti.com>

On Mon, Jun 10, 2019 at 7:12 PM Grygorii Strashko
<grygorii.strashko@ti.com> wrote:

> From: Russell King <rmk+kernel@armlinux.org.uk>
>
> Architectures are single-copy atomic, which means that simply reading
> a register is an inherently atomic operation.  There is no need to
> take a spinlock here.
>
> Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>
> Signed-off-by: Grygorii Strashko <grygorii.strashko@ti.com>

Patch applied.

This makes me wonder how many more instances we have
of this kind of mistake in the kernel :/ I guess it is mostly
harmless but it sure makes for massive code complexity.

I would sure like e.g. drivers/gpio/gpio-mmio.c to avoid
taking locks on architectures where this is not a problem
given it is used on a plethora of architectures.

Yours,
Linus Walleij

  reply	other threads:[~2019-06-12  8:47 UTC|newest]

Thread overview: 65+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-06-10 17:10 [PATCH-next 00/20] gpio: gpio-omap: set of fixes and big clean-up Grygorii Strashko
2019-06-10 17:10 ` Grygorii Strashko
2019-06-10 17:10 ` [PATCH-next 01/20] gpio: gpio-omap: ensure irq is enabled before wakeup Grygorii Strashko
2019-06-10 17:10   ` Grygorii Strashko
2019-06-12  7:54   ` Linus Walleij
2019-06-10 17:10 ` [PATCH-next 02/20] gpio: gpio-omap: fix lack of irqstatus_raw0 for OMAP4 Grygorii Strashko
2019-06-10 17:10   ` Grygorii Strashko
2019-06-12  7:55   ` Linus Walleij
2019-06-10 17:10 ` [PATCH-next 03/20] gpio: gpio-omap: remove remainder of list management Grygorii Strashko
2019-06-10 17:10   ` Grygorii Strashko
2019-06-12  7:56   ` Linus Walleij
2019-06-10 17:10 ` [PATCH-next 04/20] gpio: gpio-omap: clean up edge interrupt handling Grygorii Strashko
2019-06-10 17:10   ` Grygorii Strashko
2019-06-12  7:57   ` Linus Walleij
2019-06-10 17:10 ` [PATCH-next 05/20] gpio: gpio-omap: remove irq_ack method Grygorii Strashko
2019-06-10 17:10   ` Grygorii Strashko
2019-06-12  8:42   ` Linus Walleij
2019-06-10 17:10 ` [PATCH-next 06/20] gpio: gpio-omap: move omap_gpio_request() and omap_gpio_free() Grygorii Strashko
2019-06-10 17:10   ` Grygorii Strashko
2019-06-12  8:43   ` Linus Walleij
2019-06-10 17:10 ` [PATCH-next 07/20] gpio: gpio-omap: simplify omap_gpio_get_direction() Grygorii Strashko
2019-06-10 17:10   ` Grygorii Strashko
2019-06-12  8:47   ` Linus Walleij [this message]
2019-06-10 17:10 ` [PATCH-next 08/20] gpio: gpio-omap: simplify get() method Grygorii Strashko
2019-06-10 17:10   ` Grygorii Strashko
2019-06-12  8:49   ` Linus Walleij
2019-06-10 17:10 ` [PATCH-next 09/20] gpio: gpio-omap: simplify get_multiple() Grygorii Strashko
2019-06-10 17:10   ` Grygorii Strashko
2019-06-12  8:50   ` Linus Walleij
2019-06-10 17:10 ` [PATCH-next 10/20] gpio: gpio-omap: simplify set_multiple() Grygorii Strashko
2019-06-10 17:10   ` Grygorii Strashko
2019-06-12  8:51   ` Linus Walleij
2019-06-10 17:10 ` [PATCH-next 11/20] gpio: gpio-omap: simplify bank->level_mask Grygorii Strashko
2019-06-10 17:10   ` Grygorii Strashko
2019-06-10 17:10 ` [PATCH-next 12/20] gpio: gpio-omap: simplify read-modify-write Grygorii Strashko
2019-06-10 17:10   ` Grygorii Strashko
2019-06-12  8:53   ` Linus Walleij
2019-06-10 17:10 ` [PATCH-next 13/20] gpio: gpio-omap: simplify omap_toggle_gpio_edge_triggering() Grygorii Strashko
2019-06-10 17:10   ` Grygorii Strashko
2019-06-12  8:54   ` Linus Walleij
2019-06-10 17:10 ` [PATCH-next 14/20] gpio: gpio-omap: simplify omap_set_gpio_irqenable() Grygorii Strashko
2019-06-10 17:10   ` Grygorii Strashko
2019-06-12  8:54   ` Linus Walleij
2019-06-10 17:10 ` [PATCH-next 15/20] gpio: gpio-omap: remove dataout variation in context handling Grygorii Strashko
2019-06-10 17:10   ` Grygorii Strashko
2019-06-12  8:55   ` Linus Walleij
2019-06-10 17:10 ` [PATCH-next 16/20] gpio: gpio-omap: clean up omap_gpio_restore_context() Grygorii Strashko
2019-06-10 17:10   ` Grygorii Strashko
2019-06-12  8:56   ` Linus Walleij
2019-06-10 17:11 ` [PATCH-next 17/20] gpio: gpio-omap: constify register tables Grygorii Strashko
2019-06-10 17:11   ` Grygorii Strashko
2019-06-12  8:57   ` Linus Walleij
2019-06-10 17:11 ` [PATCH-next 18/20] gpio: gpio-omap: clean up wakeup handling Grygorii Strashko
2019-06-10 17:11   ` Grygorii Strashko
2019-06-12  8:58   ` Linus Walleij
2019-06-10 17:11 ` [PATCH-next 19/20] gpio: gpio-omap: irq_startup() must not return error codes Grygorii Strashko
2019-06-10 17:11   ` Grygorii Strashko
2019-06-12  8:59   ` Linus Walleij
2019-06-10 17:11 ` [PATCH-next 20/20] gpio: gpio-omap: clean up register access in omap2_set_gpio_debounce() Grygorii Strashko
2019-06-10 17:11   ` Grygorii Strashko
2019-06-12  9:11   ` Linus Walleij
2019-06-17 18:57     ` grygorii
2019-06-18 11:28       ` Linus Walleij
2019-06-11  7:37 ` [PATCH-next 00/20] gpio: gpio-omap: set of fixes and big clean-up Tony Lindgren
2019-06-12  9:23 ` Linus Walleij

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