* Greg KH ([email protected]) wrote: > I don't see the patch below in Linus's tree. If it's there, what is the > git commit id? >
As I pointed out in an earlier reply, this patch is bogus and adds racy data structure updates. It should not be merged. Venkatesh is working on a proper fix. Mathieu > thanks, > > greg k-h > > On Thu, Jun 25, 2009 at 04:01:24PM +0200, Thomas Renninger wrote: > > Comment from Venkatesh: > > ... > > This mutex is just serializing the changes to those variables. I could't > > think of any functionality issues of not having the lock as such. > > > > -> rip it out. > > > > CC: Venkatesh Pallipadi <[email protected]> > > Signed-off-by: Thomas Renninger <[email protected]> > > --- > > drivers/cpufreq/cpufreq_conservative.c | 61 > > +++----------------------------- > > drivers/cpufreq/cpufreq_ondemand.c | 48 +++---------------------- > > 2 files changed, 10 insertions(+), 99 deletions(-) > > > > diff --git a/drivers/cpufreq/cpufreq_conservative.c > > b/drivers/cpufreq/cpufreq_conservative.c > > index 7a74d17..6303379 100644 > > --- a/drivers/cpufreq/cpufreq_conservative.c > > +++ b/drivers/cpufreq/cpufreq_conservative.c > > @@ -18,7 +18,6 @@ > > #include <linux/cpu.h> > > #include <linux/jiffies.h> > > #include <linux/kernel_stat.h> > > -#include <linux/mutex.h> > > #include <linux/hrtimer.h> > > #include <linux/tick.h> > > #include <linux/ktime.h> > > @@ -84,19 +83,6 @@ static DEFINE_PER_CPU(struct cpu_dbs_info_s, > > cpu_dbs_info); > > > > static unsigned int dbs_enable; /* number of CPUs using this policy */ > > > > -/* > > - * DEADLOCK ALERT! There is a ordering requirement between cpu_hotplug > > - * lock and dbs_mutex. cpu_hotplug lock should always be held before > > - * dbs_mutex. If any function that can potentially take cpu_hotplug lock > > - * (like __cpufreq_driver_target()) is being called with dbs_mutex taken, > > then > > - * cpu_hotplug lock should be taken before that. Note that cpu_hotplug lock > > - * is recursive for the same process. -Venki > > - * DEADLOCK ALERT! (2) : do_dbs_timer() must not take the dbs_mutex, > > because it > > - * would deadlock with cancel_delayed_work_sync(), which is needed for > > proper > > - * raceless workqueue teardown. > > - */ > > -static DEFINE_MUTEX(dbs_mutex); > > - > > static struct workqueue_struct *kconservative_wq; > > > > static struct dbs_tuners { > > @@ -236,10 +222,7 @@ static ssize_t store_sampling_down_factor(struct > > cpufreq_policy *unused, > > if (ret != 1 || input > MAX_SAMPLING_DOWN_FACTOR || input < 1) > > return -EINVAL; > > > > - mutex_lock(&dbs_mutex); > > dbs_tuners_ins.sampling_down_factor = input; > > - mutex_unlock(&dbs_mutex); > > - > > return count; > > } > > > > @@ -253,10 +236,7 @@ static ssize_t store_sampling_rate(struct > > cpufreq_policy *unused, > > if (ret != 1) > > return -EINVAL; > > > > - mutex_lock(&dbs_mutex); > > dbs_tuners_ins.sampling_rate = max(input, minimum_sampling_rate()); > > - mutex_unlock(&dbs_mutex); > > - > > return count; > > } > > > > @@ -267,16 +247,11 @@ static ssize_t store_up_threshold(struct > > cpufreq_policy *unused, > > int ret; > > ret = sscanf(buf, "%u", &input); > > > > - mutex_lock(&dbs_mutex); > > if (ret != 1 || input > 100 || > > - input <= dbs_tuners_ins.down_threshold) { > > - mutex_unlock(&dbs_mutex); > > + input <= dbs_tuners_ins.down_threshold) > > return -EINVAL; > > - } > > > > dbs_tuners_ins.up_threshold = input; > > - mutex_unlock(&dbs_mutex); > > - > > return count; > > } > > > > @@ -287,17 +262,12 @@ static ssize_t store_down_threshold(struct > > cpufreq_policy *unused, > > int ret; > > ret = sscanf(buf, "%u", &input); > > > > - mutex_lock(&dbs_mutex); > > /* cannot be lower than 11 otherwise freq will not fall */ > > if (ret != 1 || input < 11 || input > 100 || > > - input >= dbs_tuners_ins.up_threshold) { > > - mutex_unlock(&dbs_mutex); > > + input >= dbs_tuners_ins.up_threshold) > > return -EINVAL; > > - } > > > > dbs_tuners_ins.down_threshold = input; > > - mutex_unlock(&dbs_mutex); > > - > > return count; > > } > > > > @@ -316,11 +286,9 @@ static ssize_t store_ignore_nice_load(struct > > cpufreq_policy *policy, > > if (input > 1) > > input = 1; > > > > - mutex_lock(&dbs_mutex); > > - if (input == dbs_tuners_ins.ignore_nice) { /* nothing to do */ > > - mutex_unlock(&dbs_mutex); > > + if (input == dbs_tuners_ins.ignore_nice) /* nothing to do */ > > return count; > > - } > > + > > dbs_tuners_ins.ignore_nice = input; > > > > /* we need to re-evaluate prev_cpu_idle */ > > @@ -332,8 +300,6 @@ static ssize_t store_ignore_nice_load(struct > > cpufreq_policy *policy, > > if (dbs_tuners_ins.ignore_nice) > > dbs_info->prev_cpu_nice = kstat_cpu(j).cpustat.nice; > > } > > - mutex_unlock(&dbs_mutex); > > - > > return count; > > } > > > > @@ -352,10 +318,7 @@ static ssize_t store_freq_step(struct cpufreq_policy > > *policy, > > > > /* no need to test here if freq_step is zero as the user might actually > > * want this, they would be crazy though :) */ > > - mutex_lock(&dbs_mutex); > > dbs_tuners_ins.freq_step = input; > > - mutex_unlock(&dbs_mutex); > > - > > return count; > > } > > > > @@ -566,13 +529,9 @@ static int cpufreq_governor_dbs(struct cpufreq_policy > > *policy, > > if (this_dbs_info->enable) /* Already enabled */ > > break; > > > > - mutex_lock(&dbs_mutex); > > - > > rc = sysfs_create_group(&policy->kobj, &dbs_attr_group); > > - if (rc) { > > - mutex_unlock(&dbs_mutex); > > + if (rc) > > return rc; > > - } > > > > for_each_cpu(j, policy->cpus) { > > struct cpu_dbs_info_s *j_dbs_info; > > @@ -612,13 +571,9 @@ static int cpufreq_governor_dbs(struct cpufreq_policy > > *policy, > > CPUFREQ_TRANSITION_NOTIFIER); > > } > > dbs_timer_init(this_dbs_info); > > - > > - mutex_unlock(&dbs_mutex); > > - > > break; > > > > case CPUFREQ_GOV_STOP: > > - mutex_lock(&dbs_mutex); > > dbs_timer_exit(this_dbs_info); > > sysfs_remove_group(&policy->kobj, &dbs_attr_group); > > dbs_enable--; > > @@ -631,13 +586,9 @@ static int cpufreq_governor_dbs(struct cpufreq_policy > > *policy, > > cpufreq_unregister_notifier( > > &dbs_cpufreq_notifier_block, > > CPUFREQ_TRANSITION_NOTIFIER); > > - > > - mutex_unlock(&dbs_mutex); > > - > > break; > > > > case CPUFREQ_GOV_LIMITS: > > - mutex_lock(&dbs_mutex); > > if (policy->max < this_dbs_info->cur_policy->cur) > > __cpufreq_driver_target( > > this_dbs_info->cur_policy, > > @@ -646,8 +597,6 @@ static int cpufreq_governor_dbs(struct cpufreq_policy > > *policy, > > __cpufreq_driver_target( > > this_dbs_info->cur_policy, > > policy->min, CPUFREQ_RELATION_L); > > - mutex_unlock(&dbs_mutex); > > - > > break; > > } > > return 0; > > diff --git a/drivers/cpufreq/cpufreq_ondemand.c > > b/drivers/cpufreq/cpufreq_ondemand.c > > index e741c33..d080a48 100644 > > --- a/drivers/cpufreq/cpufreq_ondemand.c > > +++ b/drivers/cpufreq/cpufreq_ondemand.c > > @@ -17,7 +17,6 @@ > > #include <linux/cpu.h> > > #include <linux/jiffies.h> > > #include <linux/kernel_stat.h> > > -#include <linux/mutex.h> > > #include <linux/hrtimer.h> > > #include <linux/tick.h> > > #include <linux/ktime.h> > > @@ -91,19 +90,6 @@ static DEFINE_PER_CPU(struct cpu_dbs_info_s, > > cpu_dbs_info); > > > > static unsigned int dbs_enable; /* number of CPUs using this policy */ > > > > -/* > > - * DEADLOCK ALERT! There is a ordering requirement between cpu_hotplug > > - * lock and dbs_mutex. cpu_hotplug lock should always be held before > > - * dbs_mutex. If any function that can potentially take cpu_hotplug lock > > - * (like __cpufreq_driver_target()) is being called with dbs_mutex taken, > > then > > - * cpu_hotplug lock should be taken before that. Note that cpu_hotplug lock > > - * is recursive for the same process. -Venki > > - * DEADLOCK ALERT! (2) : do_dbs_timer() must not take the dbs_mutex, > > because it > > - * would deadlock with cancel_delayed_work_sync(), which is needed for > > proper > > - * raceless workqueue teardown. > > - */ > > -static DEFINE_MUTEX(dbs_mutex); > > - > > static struct workqueue_struct *kondemand_wq; > > > > static struct dbs_tuners { > > @@ -269,14 +255,10 @@ static ssize_t store_sampling_rate(struct > > cpufreq_policy *unused, > > int ret; > > ret = sscanf(buf, "%u", &input); > > > > - mutex_lock(&dbs_mutex); > > - if (ret != 1) { > > - mutex_unlock(&dbs_mutex); > > + if (ret != 1) > > return -EINVAL; > > - } > > - dbs_tuners_ins.sampling_rate = max(input, minimum_sampling_rate()); > > - mutex_unlock(&dbs_mutex); > > > > + dbs_tuners_ins.sampling_rate = max(input, minimum_sampling_rate()); > > return count; > > } > > > > @@ -287,16 +269,11 @@ static ssize_t store_up_threshold(struct > > cpufreq_policy *unused, > > int ret; > > ret = sscanf(buf, "%u", &input); > > > > - mutex_lock(&dbs_mutex); > > if (ret != 1 || input > MAX_FREQUENCY_UP_THRESHOLD || > > - input < MIN_FREQUENCY_UP_THRESHOLD) { > > - mutex_unlock(&dbs_mutex); > > + input < MIN_FREQUENCY_UP_THRESHOLD) > > return -EINVAL; > > - } > > > > dbs_tuners_ins.up_threshold = input; > > - mutex_unlock(&dbs_mutex); > > - > > return count; > > } > > > > @@ -315,11 +292,9 @@ static ssize_t store_ignore_nice_load(struct > > cpufreq_policy *policy, > > if (input > 1) > > input = 1; > > > > - mutex_lock(&dbs_mutex); > > - if (input == dbs_tuners_ins.ignore_nice) { /* nothing to do */ > > - mutex_unlock(&dbs_mutex); > > + if (input == dbs_tuners_ins.ignore_nice) /* nothing to do */ > > return count; > > - } > > + > > dbs_tuners_ins.ignore_nice = input; > > > > /* we need to re-evaluate prev_cpu_idle */ > > @@ -332,8 +307,6 @@ static ssize_t store_ignore_nice_load(struct > > cpufreq_policy *policy, > > dbs_info->prev_cpu_nice = kstat_cpu(j).cpustat.nice; > > > > } > > - mutex_unlock(&dbs_mutex); > > - > > return count; > > } > > > > @@ -350,10 +323,8 @@ static ssize_t store_powersave_bias(struct > > cpufreq_policy *unused, > > if (input > 1000) > > input = 1000; > > > > - mutex_lock(&dbs_mutex); > > dbs_tuners_ins.powersave_bias = input; > > ondemand_powersave_bias_init(); > > - mutex_unlock(&dbs_mutex); > > > > return count; > > } > > @@ -586,13 +557,11 @@ static int cpufreq_governor_dbs(struct cpufreq_policy > > *policy, > > if (this_dbs_info->enable) /* Already enabled */ > > break; > > > > - mutex_lock(&dbs_mutex); > > dbs_enable++; > > > > rc = sysfs_create_group(&policy->kobj, &dbs_attr_group); > > if (rc) { > > dbs_enable--; > > - mutex_unlock(&dbs_mutex); > > return rc; > > } > > > > @@ -627,28 +596,21 @@ static int cpufreq_governor_dbs(struct cpufreq_policy > > *policy, > > dbs_tuners_ins.sampling_rate = def_sampling_rate; > > } > > dbs_timer_init(this_dbs_info); > > - > > - mutex_unlock(&dbs_mutex); > > break; > > > > case CPUFREQ_GOV_STOP: > > - mutex_lock(&dbs_mutex); > > dbs_timer_exit(this_dbs_info); > > sysfs_remove_group(&policy->kobj, &dbs_attr_group); > > dbs_enable--; > > - mutex_unlock(&dbs_mutex); > > - > > break; > > > > case CPUFREQ_GOV_LIMITS: > > - mutex_lock(&dbs_mutex); > > if (policy->max < this_dbs_info->cur_policy->cur) > > __cpufreq_driver_target(this_dbs_info->cur_policy, > > policy->max, CPUFREQ_RELATION_H); > > else if (policy->min > this_dbs_info->cur_policy->cur) > > __cpufreq_driver_target(this_dbs_info->cur_policy, > > policy->min, CPUFREQ_RELATION_L); > > - mutex_unlock(&dbs_mutex); > > break; > > } > > return 0; > > -- > > 1.6.0.2 > > > > -- > > To unsubscribe from this list: send the line "unsubscribe cpufreq" in > > the body of a message to [email protected] > > More majordomo info at http://vger.kernel.org/majordomo-info.html > > > > _______________________________________________ > > stable mailing list > > [email protected] > > http://linux.kernel.org/mailman/listinfo/stable -- Mathieu Desnoyers OpenPGP key fingerprint: 8CD5 52C3 8E3C 4140 715F BA06 3F25 A8FE 3BAE 9A68 -- To unsubscribe from this list: send the line "unsubscribe kernel-testers" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html
