cpufreq/sparc-us2e: Replace racy task affinity logic
authorThomas Gleixner <tglx@linutronix.de>
Thu, 13 Apr 2017 08:22:43 +0000 (10:22 +0200)
committerThomas Gleixner <tglx@linutronix.de>
Sat, 15 Apr 2017 10:20:56 +0000 (12:20 +0200)
commit12699ac53a2e5fbd1fd7c164b11685d55c8aa28b
tree9646a2261f6e8d7ca4f48e3357fd639cbd1709c9
parent9fe24c4e92d3963d92d7d383e28ed098bd5689d8
cpufreq/sparc-us2e: Replace racy task affinity logic

The access to the HBIRD_ESTAR_MODE register in the cpu frequency control
functions must happen on the target CPU. This is achieved by temporarily
setting the affinity of the calling user space thread to the requested CPU
and reset it to the original affinity afterwards.

That's racy vs. CPU hotplug and concurrent affinity settings for that
thread resulting in code executing on the wrong CPU and overwriting the
new affinity setting.

Replace it by a straight forward smp function call.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
Cc: Fenghua Yu <fenghua.yu@intel.com>
Cc: Tony Luck <tony.luck@intel.com>
Cc: Herbert Xu <herbert@gondor.apana.org.au>
Cc: "Rafael J. Wysocki" <rjw@rjwysocki.net>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Sebastian Siewior <bigeasy@linutronix.de>
Cc: linux-pm@vger.kernel.org
Cc: Lai Jiangshan <jiangshanlai@gmail.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Tejun Heo <tj@kernel.org>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Len Brown <lenb@kernel.org>
Link: http://lkml.kernel.org/r/alpine.DEB.2.20.1704131020280.2408@nanos
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
drivers/cpufreq/sparc-us2e-cpufreq.c