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cpufreq/sh: Replace racy task affinity logic

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The target() callback must run on the affected cpu. This is achieved by
temporarily setting the affinity of the calling thread to the requested CPU
and reset it to the original affinity afterwards.

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

Replace it by work_on_cpu(). All call pathes which invoke the callbacks are
already protected against CPU hotplug.

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/20170412201042.958216363@linutronix.de
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
This commit is contained in:
Thomas Gleixner 2017-04-12 22:07:36 +02:00
parent 38f05ed04b
commit 205dcc1ecb
1 changed files with 42 additions and 33 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

75
drivers/cpufreq/sh-cpufreq.c
View file

@ -30,11 +30,51 @@
static DEFINE_PER_CPU(struct clk, sh_cpuclk);
struct cpufreq_target {
struct cpufreq_policy *policy;
unsigned int freq;
};
static unsigned int sh_cpufreq_get(unsigned int cpu)
{
return (clk_get_rate(&per_cpu(sh_cpuclk, cpu)) + 500) / 1000;
}
static long __sh_cpufreq_target(void *arg)
{
struct cpufreq_target *target = arg;
struct cpufreq_policy *policy = target->policy;
int cpu = policy->cpu;
struct clk *cpuclk = &per_cpu(sh_cpuclk, cpu);
struct cpufreq_freqs freqs;
struct device *dev;
long freq;
if (smp_processor_id() != cpu)
return -ENODEV;
dev = get_cpu_device(cpu);
/* Convert target_freq from kHz to Hz */
freq = clk_round_rate(cpuclk, target->freq * 1000);
if (freq < (policy->min * 1000) || freq > (policy->max * 1000))
return -EINVAL;
dev_dbg(dev, "requested frequency %u Hz\n", target->freq * 1000);
freqs.old = sh_cpufreq_get(cpu);
freqs.new = (freq + 500) / 1000;
freqs.flags = 0;
cpufreq_freq_transition_begin(target->policy, &freqs);
clk_set_rate(cpuclk, freq);
cpufreq_freq_transition_end(target->policy, &freqs, 0);
dev_dbg(dev, "set frequency %lu Hz\n", freq);
return 0;
}
/*
* Here we notify other drivers of the proposed change and the final change.
*/
@ -42,40 +82,9 @@ static int sh_cpufreq_target(struct cpufreq_policy *policy,
unsigned int target_freq,
unsigned int relation)
{
unsigned int cpu = policy->cpu;
struct clk *cpuclk = &per_cpu(sh_cpuclk, cpu);
cpumask_t cpus_allowed;
struct cpufreq_freqs freqs;
struct device *dev;
long freq;
struct cpufreq_target data = { .policy = policy, .freq = target_freq };
cpus_allowed = current->cpus_allowed;
set_cpus_allowed_ptr(current, cpumask_of(cpu));
BUG_ON(smp_processor_id() != cpu);
dev = get_cpu_device(cpu);
/* Convert target_freq from kHz to Hz */
freq = clk_round_rate(cpuclk, target_freq * 1000);
if (freq < (policy->min * 1000) || freq > (policy->max * 1000))
return -EINVAL;
dev_dbg(dev, "requested frequency %u Hz\n", target_freq * 1000);
freqs.old = sh_cpufreq_get(cpu);
freqs.new = (freq + 500) / 1000;
freqs.flags = 0;
cpufreq_freq_transition_begin(policy, &freqs);
set_cpus_allowed_ptr(current, &cpus_allowed);
clk_set_rate(cpuclk, freq);
cpufreq_freq_transition_end(policy, &freqs, 0);
dev_dbg(dev, "set frequency %lu Hz\n", freq);
return 0;
return work_on_cpu(policy->cpu, __sh_cpufreq_target, &data);
}
static int sh_cpufreq_verify(struct cpufreq_policy *policy)