ia64/salinfo: Replace racy task affinity logic
authorThomas Gleixner <tglx@linutronix.de>
Wed, 12 Apr 2017 20:07:29 +0000 (22:07 +0200)
committerThomas Gleixner <tglx@linutronix.de>
Sat, 15 Apr 2017 10:20:53 +0000 (12:20 +0200)
commit67cb85fdcee7fbc61c09c00360d1a4ae37641db4
tree0e03ddce812394903dc4d91e72609940ae34eb1e
parent0e8d6a9336b487a1dd6f1991ff376e669d4c87c6
ia64/salinfo: Replace racy task affinity logic

Some of the file operations in /proc/sal require to run code on the
requested 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 using work_on_cpu_safe() which guarantees to run the code on
the requested CPU or to fail in case the CPU is offline.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Fenghua Yu <fenghua.yu@intel.com>
Cc: Tony Luck <tony.luck@intel.com>
Cc: linux-ia64@vger.kernel.org
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: Lai Jiangshan <jiangshanlai@gmail.com>
Cc: Viresh Kumar <viresh.kumar@linaro.org>
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/20170412201042.341863457@linutronix.de
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
arch/ia64/kernel/salinfo.c