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References: <20240130124828.14678-1-brgl@bgdev.pl>
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From: Linus Walleij <linus.walleij@linaro.org>
Date: Wed, 31 Jan 2024 21:32:10 +0100
Message-ID: <CACRpkdZrKGHiaQc5NVq5ceV=++SE3j7xEfwD9FBWRz0GCFpMCw@mail.gmail.com>
Subject: Re: [PATCH 00/22] gpio: rework locking and object life-time control
To: Bartosz Golaszewski <brgl@bgdev.pl>
Cc: Kent Gibson <warthog618@gmail.com>, Alex Elder <elder@linaro.org>, 
	Geert Uytterhoeven <geert+renesas@glider.be>, "Paul E . McKenney" <paulmck@kernel.org>, 
	Andy Shevchenko <andriy.shevchenko@linux.intel.com>, Wolfram Sang <wsa@the-dreams.de>, 
	linux-gpio@vger.kernel.org, linux-kernel@vger.kernel.org, 
	Bartosz Golaszewski <bartosz.golaszewski@linaro.org>
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On Tue, Jan 30, 2024 at 1:48=E2=80=AFPM Bartosz Golaszewski <brgl@bgdev.pl>=
 wrote:

> We do NOT serialize all API callbacks. This means that provider callbacks
> may be called simultaneously and GPIO drivers need to provide their own
> locking if needed. This is on purpose. First: we only support exclusive
> GPIO usage[1] so there's no risk of two drivers getting in each other's
> way over the same GPIO. Second: with this series, we ensure enough
> consistency to limit the chance of drivers or user-space users crashing
> the kernel. With additional improvements in handling the flags field in
> GPIO descriptors there's very little to gain, while bitbanging drivers
> may care about the increased performance of going lockless.

OK I read this before but didn't understand it, now I understand it.

The series:
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>

I think you should merge it all soon so we get some time to shake
it out in linux-next, hopefully any remaining bugs and cleanups
can be done in-tree.

Excellent work, by the way.

Yours,
Linus Walleij