| Message ID | 1452533760-13787-8-git-send-email-juri.lelli@arm.com (mailing list archive) |
|---|---|
| State | RFC |
| Headers | show |
On 11-01-16, 17:35, Juri Lelli wrote: > @@ -2025,6 +2027,7 @@ int cpufreq_register_governor(struct cpufreq_governor *governor) > err = -EBUSY; > if (!find_governor(governor->name)) { > err = 0; > + lockdep_assert_held(&cpufreq_governor_mutex); > list_add(&governor->governor_list, &cpufreq_governor_list); > } Why here? This is how the routine looks like: int cpufreq_register_governor(struct cpufreq_governor *governor) { int err; if (!governor) return -EINVAL; if (cpufreq_disabled()) return -ENODEV; mutex_lock(&cpufreq_governor_mutex); governor->initialized = 0; err = -EBUSY; if (!find_governor(governor->name)) { err = 0; list_add(&governor->governor_list, &cpufreq_governor_list); } mutex_unlock(&cpufreq_governor_mutex); return err; }
Hi, On 12/01/16 15:31, Viresh Kumar wrote: > On 11-01-16, 17:35, Juri Lelli wrote: > > @@ -2025,6 +2027,7 @@ int cpufreq_register_governor(struct cpufreq_governor *governor) > > err = -EBUSY; > > if (!find_governor(governor->name)) { > > err = 0; > > + lockdep_assert_held(&cpufreq_governor_mutex); > > list_add(&governor->governor_list, &cpufreq_governor_list); > > } > > Why here? This is how the routine looks like: > I guess I was simply over-paranoid. We can drop this assertion. Thanks, - Juri > int cpufreq_register_governor(struct cpufreq_governor *governor) > { > int err; > > if (!governor) > return -EINVAL; > > if (cpufreq_disabled()) > return -ENODEV; > > mutex_lock(&cpufreq_governor_mutex); > > governor->initialized = 0; > err = -EBUSY; > if (!find_governor(governor->name)) { > err = 0; > list_add(&governor->governor_list, &cpufreq_governor_list); > } > > mutex_unlock(&cpufreq_governor_mutex); > return err; > } > > > -- > viresh > -- To unsubscribe from this list: send the line "unsubscribe linux-pm" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
diff --git a/drivers/cpufreq/cpufreq.c b/drivers/cpufreq/cpufreq.c index 98adbc2..7dae7f3 100644 --- a/drivers/cpufreq/cpufreq.c +++ b/drivers/cpufreq/cpufreq.c @@ -506,6 +506,7 @@ static struct cpufreq_governor *find_governor(const char *str_governor) { struct cpufreq_governor *t; + lockdep_assert_held(&cpufreq_governor_mutex); for_each_governor(t) if (!strncasecmp(str_governor, t->name, CPUFREQ_NAME_LEN)) return t; @@ -693,6 +694,7 @@ static ssize_t show_scaling_available_governors(struct cpufreq_policy *policy, goto out; } + lockdep_assert_held(&cpufreq_governor_mutex); for_each_governor(t) { if (i >= (ssize_t) ((PAGE_SIZE / sizeof(char)) - (CPUFREQ_NAME_LEN + 2))) @@ -2025,6 +2027,7 @@ int cpufreq_register_governor(struct cpufreq_governor *governor) err = -EBUSY; if (!find_governor(governor->name)) { err = 0; + lockdep_assert_held(&cpufreq_governor_mutex); list_add(&governor->governor_list, &cpufreq_governor_list); }
cpufreq_governor_list is guarded by cpufreq_governor_mutex. Add appropriate locking assertions to check that we always access the list while holding the lock protecting it. Cc: "Rafael J. Wysocki" <rjw@rjwysocki.net> Cc: Viresh Kumar <viresh.kumar@linaro.org> Signed-off-by: Juri Lelli <juri.lelli@arm.com> --- drivers/cpufreq/cpufreq.c | 3 +++ 1 file changed, 3 insertions(+)