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cpufreq: cpufreq-cpu0: use RCU locks around usage of OPP 

OPP pointer is RCU protected, hence after finding it, de-reference
also should be protected with the same RCU context else the OPP
pointer may become invalid.

Reported-by: Jack Mitchell <jack@embed.me.uk>
Tested-by: Alexander Holler <holler@ahsoftware.de>
Tested-by: Jack Mitchell <jack@embed.me.uk>
Acked-by: Alexander Holler <holler@ahsoftware.de>
Signed-off-by: Nishanth Menon <nm@ti.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
This commit is contained in:
Nishanth Menon 2013-01-18 19:52:33 +00:00 committed by Rafael J. Wysocki
parent f44d188acd
commit 78e8eb8fea
1 changed files with 5 additions and 0 deletions
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5
drivers/cpufreq/cpufreq-cpu0.c
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@ -71,12 +71,15 @@ static int cpu0_set_target(struct cpufreq_policy *policy,
} }
if (cpu_reg) { if (cpu_reg) {
rcu_read_lock();
opp = opp_find_freq_ceil(cpu_dev, &freq_Hz); opp = opp_find_freq_ceil(cpu_dev, &freq_Hz);
if (IS_ERR(opp)) { if (IS_ERR(opp)) {
rcu_read_unlock();
pr_err("failed to find OPP for %ld\n", freq_Hz); pr_err("failed to find OPP for %ld\n", freq_Hz);
return PTR_ERR(opp); return PTR_ERR(opp);
} }
volt = opp_get_voltage(opp); volt = opp_get_voltage(opp);
rcu_read_unlock();
tol = volt * voltage_tolerance / 100; tol = volt * voltage_tolerance / 100;
volt_old = regulator_get_voltage(cpu_reg); volt_old = regulator_get_voltage(cpu_reg);
} }
@ -236,12 +239,14 @@ static int cpu0_cpufreq_driver_init(void)
*/ */
for (i = 0; freq_table[i].frequency != CPUFREQ_TABLE_END; i++) for (i = 0; freq_table[i].frequency != CPUFREQ_TABLE_END; i++)
; ;
rcu_read_lock();
opp = opp_find_freq_exact(cpu_dev, opp = opp_find_freq_exact(cpu_dev,
freq_table[0].frequency * 1000, true); freq_table[0].frequency * 1000, true);
min_uV = opp_get_voltage(opp); min_uV = opp_get_voltage(opp);
opp = opp_find_freq_exact(cpu_dev, opp = opp_find_freq_exact(cpu_dev,
freq_table[i-1].frequency * 1000, true); freq_table[i-1].frequency * 1000, true);
max_uV = opp_get_voltage(opp); max_uV = opp_get_voltage(opp);
rcu_read_unlock();
ret = regulator_set_voltage_time(cpu_reg, min_uV, max_uV); ret = regulator_set_voltage_time(cpu_reg, min_uV, max_uV);
if (ret > 0) if (ret > 0)
transition_latency += ret * 1000; transition_latency += ret * 1000;