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Date:   Thu, 11 May 2023 09:48:05 +0300
From:   Tony Lindgren <tony@atomide.com>
To:     Geert Uytterhoeven <geert+renesas@glider.be>
Cc:     Stephen Boyd <sboyd@kernel.org>,
        Tomasz Figa <tomasz.figa@gmail.com>,
        Sylwester Nawrocki <s.nawrocki@samsung.com>,
        Will Deacon <will@kernel.org>, Arnd Bergmann <arnd@arndb.de>,
        Wolfram Sang <wsa+renesas@sang-engineering.com>,
        Dejin Zheng <zhengdejin5@gmail.com>,
        Kai-Heng Feng <kai.heng.feng@canonical.com>,
        Nicholas Piggin <npiggin@gmail.com>,
        Heiko Carstens <hca@linux.ibm.com>,
        Peter Zijlstra <peterz@infradead.org>,
        Russell King <linux@armlinux.org.uk>,
        John Stultz <jstultz@google.com>,
        Thomas Gleixner <tglx@linutronix.de>,
        Krzysztof Kozlowski <krzk@kernel.org>,
        Tero Kristo <tero.kristo@linux.intel.com>,
        Ulf Hansson <ulf.hansson@linaro.org>,
        "Rafael J . Wysocki" <rafael.j.wysocki@intel.com>,
        Vincent Guittot <vincent.guittot@linaro.org>,
        linux-arm-kernel@lists.infradead.org,
        linux-renesas-soc@vger.kernel.org, linux-pm@vger.kernel.org,
        linux-kernel@vger.kernel.org
Subject: Re: [PATCH v2 2/2] iopoll: Do not use timekeeping in
 read_poll_timeout_atomic()
Message-ID: <20230511064805.GF14287@atomide.com>
References: <cover.1683722688.git.geert+renesas@glider.be>
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Hi,

* Geert Uytterhoeven <geert+renesas@glider.be> [230510 13:23]:
> read_poll_timeout_atomic() uses ktime_get() to implement the timeout
> feature, just like its non-atomic counterpart.  However, there are
> several issues with this, due to its use in atomic contexts:
> 
>   1. When called in the s2ram path (as typically done by clock or PM
>      domain drivers), timekeeping may be suspended, triggering the
>      WARN_ON(timekeeping_suspended) in ktime_get():

Maybe add a comment to read_poll_timeout_atomic() saying it can be
used also with timekeeping_suspended?

Otherwise a few years later it might get broken when somebody goes
to patch it without testing it with timekeeping_suspended :)

Other than that looks good to me:

Reviewed-by: Tony Lindgren <tony@atomide.com>