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()
Date: Thu, 11 May 2023 09:48:05 +0300 [thread overview]
Message-ID: <20230511064805.GF14287@atomide.com> (raw)
In-Reply-To: <8db63020d18fc22e137e4a8f0aa15e6b9949a6f6.1683722688.git.geert+renesas@glider.be>
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>
next prev parent reply other threads:[~2023-05-11 6:48 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-05-10 13:23 [PATCH v2 0/2] iopoll: Busy loop and timeout improvements Geert Uytterhoeven
2023-05-10 13:23 ` [PATCH v2 1/2] iopoll: Call cpu_relax() in busy loops Geert Uytterhoeven
2023-05-11 6:48 ` Tony Lindgren
2023-05-11 10:48 ` David Laight
2023-05-23 7:29 ` Geert Uytterhoeven
2023-05-23 8:55 ` David Laight
2023-05-11 9:48 ` Ulf Hansson
2023-05-10 13:23 ` [PATCH v2 2/2] iopoll: Do not use timekeeping in read_poll_timeout_atomic() Geert Uytterhoeven
2023-05-10 13:35 ` Arnd Bergmann
2023-05-10 13:46 ` Geert Uytterhoeven
2023-05-10 13:56 ` Arnd Bergmann
2023-05-11 6:48 ` Tony Lindgren [this message]
2023-05-11 10:26 ` Ulf Hansson
2023-05-11 12:44 ` Geert Uytterhoeven
2023-05-12 7:53 ` Ulf Hansson
2023-05-12 8:03 ` Geert Uytterhoeven
2023-05-15 9:26 ` Ulf Hansson
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