cpufreq/sparc-us3: Replace racy task affinity logic
authorThomas Gleixner <tglx@linutronix.de>
Wed, 12 Apr 2017 20:07:37 +0000 (22:07 +0200)
committerThomas Gleixner <tglx@linutronix.de>
Sat, 15 Apr 2017 10:20:55 +0000 (12:20 +0200)
commit9fe24c4e92d3963d92d7d383e28ed098bd5689d8
tree1f331b3ee3445cb7d3946a38b8ee8c57a0dc626e
parent205dcc1ecbc566cbc20acf246e68de3b080b3ecf
cpufreq/sparc-us3: Replace racy task affinity logic

The access to the safari config register in the CPU frequency functions
must be executed 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/20170412201043.047558840@linutronix.de
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
drivers/cpufreq/sparc-us3-cpufreq.c