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Subject[RFC] cpufreq: Make sure target freq is within limits
Date
Hi Rafael,

__cpufreq_driver_target() must not pass target frequency beyond the limits of
current policy.

Today most of cpufreq platform drivers are doing this check in their target
routines. Why not move it to __cpufreq_driver_target().

I wanted to get your opinion on this before making changes in all driver files.
That's why this is an RFC.

Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
---
drivers/cpufreq/cpufreq.c | 11 +++++++++--
1 file changed, 9 insertions(+), 2 deletions(-)

diff --git a/drivers/cpufreq/cpufreq.c b/drivers/cpufreq/cpufreq.c
index f552d5f..59264f1 100644
--- a/drivers/cpufreq/cpufreq.c
+++ b/drivers/cpufreq/cpufreq.c
@@ -1470,12 +1470,19 @@ int __cpufreq_driver_target(struct cpufreq_policy *policy,
unsigned int relation)
{
int retval = -EINVAL;
+ unsigned int old_target_freq = target_freq;

if (cpufreq_disabled())
return -ENODEV;

- pr_debug("target for CPU %u: %u kHz, relation %u\n", policy->cpu,
- target_freq, relation);
+ /* Make sure that target_freq is within supported range */
+ if (target_freq > policy->max)
+ target_freq = policy->max;
+ if (target_freq < policy->min)
+ target_freq = policy->min;
+
+ pr_debug("target for CPU %u: %u kHz, relation %u, requested %u kHz\n",
+ policy->cpu, target_freq, relation, old_target_freq);
if (cpu_online(policy->cpu) && cpufreq_driver->target)
retval = cpufreq_driver->target(policy, target_freq, relation);

--
1.7.12.rc2.18.g61b472e



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