From cffe4e0e7413eb29fb8bd035c8b12b33a4b8522a Mon Sep 17 00:00:00 2001 From: Stratos Karafotis Date: Wed, 5 Jun 2013 19:01:50 +0300 Subject: cpufreq: Remove unused function __cpufreq_driver_getavg() The target frequency calculation method in the ondemand governor has changed and it is now independent of the measured average frequency. Consequently, the __cpufreq_driver_getavg() function and getavg member of struct cpufreq_driver are not used any more, so drop them. [rjw: Changelog] Signed-off-by: Stratos Karafotis Acked-by: Viresh Kumar Signed-off-by: Rafael J. Wysocki --- drivers/cpufreq/cpufreq.c | 12 ------------ 1 file changed, 12 deletions(-) (limited to 'drivers/cpufreq/cpufreq.c') diff --git a/drivers/cpufreq/cpufreq.c b/drivers/cpufreq/cpufreq.c index a4ad7339588d..9a9d8ee9faec 100644 --- a/drivers/cpufreq/cpufreq.c +++ b/drivers/cpufreq/cpufreq.c @@ -1593,18 +1593,6 @@ fail: } EXPORT_SYMBOL_GPL(cpufreq_driver_target); -int __cpufreq_driver_getavg(struct cpufreq_policy *policy, unsigned int cpu) -{ - if (cpufreq_disabled()) - return 0; - - if (!cpufreq_driver->getavg) - return 0; - - return cpufreq_driver->getavg(policy, cpu); -} -EXPORT_SYMBOL_GPL(__cpufreq_driver_getavg); - /* * when "event" is CPUFREQ_GOV_LIMITS */ -- cgit v1.2.3 From 23d328994b548d6822b88fe7e1903652afc354e0 Mon Sep 17 00:00:00 2001 From: "Srivatsa S. Bhat" Date: Tue, 30 Jul 2013 04:23:56 +0530 Subject: cpufreq: Fix misplaced call to cpufreq_update_policy() The call to cpufreq_update_policy() is placed in the CPU hotplug callback of cpufreq_stats, which has a higher priority than the CPU hotplug callback of cpufreq-core. As a result, during CPU_ONLINE/CPU_ONLINE_FROZEN, we end up calling cpufreq_update_policy() *before* calling cpufreq_add_dev() ! And for uninitialized CPUs, it just returns silently, not doing anything. To add to that, cpufreq_stats is not even the right place to call cpufreq_update_policy() to begin with. The cpufreq core ought to handle this in its own callback, from an elegance/relevance perspective. So move the invocation of cpufreq_update_policy() to cpufreq_cpu_callback, and place it *after* cpufreq_add_dev(). Signed-off-by: Srivatsa S. Bhat Acked-by: Viresh Kumar Signed-off-by: Rafael J. Wysocki --- drivers/cpufreq/cpufreq.c | 1 + 1 file changed, 1 insertion(+) (limited to 'drivers/cpufreq/cpufreq.c') diff --git a/drivers/cpufreq/cpufreq.c b/drivers/cpufreq/cpufreq.c index f0a5e2b0eb8a..5b317b0db902 100644 --- a/drivers/cpufreq/cpufreq.c +++ b/drivers/cpufreq/cpufreq.c @@ -1945,6 +1945,7 @@ static int cpufreq_cpu_callback(struct notifier_block *nfb, case CPU_ONLINE: case CPU_ONLINE_FROZEN: cpufreq_add_dev(dev, NULL); + cpufreq_update_policy(cpu); break; case CPU_DOWN_PREPARE: case CPU_DOWN_PREPARE_FROZEN: -- cgit v1.2.3 From e9698cc5d2749c5b74e137f94a95d7e505b097e8 Mon Sep 17 00:00:00 2001 From: "Srivatsa S. Bhat" Date: Tue, 30 Jul 2013 04:24:11 +0530 Subject: cpufreq: Add helper to perform alloc/free of policy structure Separate out the allocation of the cpufreq policy structure (along with its error handling) to a helper function. This makes the code easier to read and also helps with some upcoming code reorganization. Signed-off-by: Srivatsa S. Bhat Acked-by: Viresh Kumar Signed-off-by: Rafael J. Wysocki --- drivers/cpufreq/cpufreq.c | 49 ++++++++++++++++++++++++++++++++--------------- 1 file changed, 34 insertions(+), 15 deletions(-) (limited to 'drivers/cpufreq/cpufreq.c') diff --git a/drivers/cpufreq/cpufreq.c b/drivers/cpufreq/cpufreq.c index 5b317b0db902..18e58c1bfd66 100644 --- a/drivers/cpufreq/cpufreq.c +++ b/drivers/cpufreq/cpufreq.c @@ -944,6 +944,37 @@ static int cpufreq_add_policy_cpu(unsigned int cpu, unsigned int sibling, } #endif +static struct cpufreq_policy *cpufreq_policy_alloc(void) +{ + struct cpufreq_policy *policy; + + policy = kzalloc(sizeof(*policy), GFP_KERNEL); + if (!policy) + return NULL; + + if (!alloc_cpumask_var(&policy->cpus, GFP_KERNEL)) + goto err_free_policy; + + if (!zalloc_cpumask_var(&policy->related_cpus, GFP_KERNEL)) + goto err_free_cpumask; + + return policy; + +err_free_cpumask: + free_cpumask_var(policy->cpus); +err_free_policy: + kfree(policy); + + return NULL; +} + +static void cpufreq_policy_free(struct cpufreq_policy *policy) +{ + free_cpumask_var(policy->related_cpus); + free_cpumask_var(policy->cpus); + kfree(policy); +} + /** * cpufreq_add_dev - add a CPU device * @@ -997,16 +1028,10 @@ static int cpufreq_add_dev(struct device *dev, struct subsys_interface *sif) goto module_out; } - policy = kzalloc(sizeof(struct cpufreq_policy), GFP_KERNEL); + policy = cpufreq_policy_alloc(); if (!policy) goto nomem_out; - if (!alloc_cpumask_var(&policy->cpus, GFP_KERNEL)) - goto err_free_policy; - - if (!zalloc_cpumask_var(&policy->related_cpus, GFP_KERNEL)) - goto err_free_cpumask; - policy->cpu = cpu; policy->governor = CPUFREQ_DEFAULT_GOVERNOR; cpumask_copy(policy->cpus, cpumask_of(cpu)); @@ -1071,11 +1096,7 @@ err_out_unregister: err_set_policy_cpu: per_cpu(cpufreq_policy_cpu, cpu) = -1; - free_cpumask_var(policy->related_cpus); -err_free_cpumask: - free_cpumask_var(policy->cpus); -err_free_policy: - kfree(policy); + cpufreq_policy_free(policy); nomem_out: module_put(cpufreq_driver->owner); module_out: @@ -1199,9 +1220,7 @@ static int __cpufreq_remove_dev(struct device *dev, if (cpufreq_driver->exit) cpufreq_driver->exit(data); - free_cpumask_var(data->related_cpus); - free_cpumask_var(data->cpus); - kfree(data); + cpufreq_policy_free(data); } else { pr_debug("%s: removing link, cpu: %d\n", __func__, cpu); cpufreq_cpu_put(data); -- cgit v1.2.3 From e18f1682bce701ddcf88ba3651e07c7ee9b3ed60 Mon Sep 17 00:00:00 2001 From: "Srivatsa S. Bhat" Date: Tue, 30 Jul 2013 04:24:23 +0530 Subject: cpufreq: Extract non-interface related stuff from cpufreq_add_dev_interface cpufreq_add_dev_interface() includes the work of exposing the interface to the device, as well as a lot of unrelated stuff. Move the latter to cpufreq_add_dev(), where it is more appropriate. Signed-off-by: Srivatsa S. Bhat Acked-by: Viresh Kumar Signed-off-by: Rafael J. Wysocki --- drivers/cpufreq/cpufreq.c | 43 ++++++++++++++++++++++++++----------------- 1 file changed, 26 insertions(+), 17 deletions(-) (limited to 'drivers/cpufreq/cpufreq.c') diff --git a/drivers/cpufreq/cpufreq.c b/drivers/cpufreq/cpufreq.c index 18e58c1bfd66..f7c58c79217d 100644 --- a/drivers/cpufreq/cpufreq.c +++ b/drivers/cpufreq/cpufreq.c @@ -835,11 +835,8 @@ static int cpufreq_add_dev_interface(unsigned int cpu, struct cpufreq_policy *policy, struct device *dev) { - struct cpufreq_policy new_policy; struct freq_attr **drv_attr; - unsigned long flags; int ret = 0; - unsigned int j; /* prepare interface data */ ret = kobject_init_and_add(&policy->kobj, &ktype_cpufreq, @@ -871,17 +868,23 @@ static int cpufreq_add_dev_interface(unsigned int cpu, goto err_out_kobj_put; } - write_lock_irqsave(&cpufreq_driver_lock, flags); - for_each_cpu(j, policy->cpus) { - per_cpu(cpufreq_cpu_data, j) = policy; - per_cpu(cpufreq_policy_cpu, j) = policy->cpu; - } - write_unlock_irqrestore(&cpufreq_driver_lock, flags); - ret = cpufreq_add_dev_symlink(cpu, policy); if (ret) goto err_out_kobj_put; + return ret; + +err_out_kobj_put: + kobject_put(&policy->kobj); + wait_for_completion(&policy->kobj_unregister); + return ret; +} + +static void cpufreq_init_policy(struct cpufreq_policy *policy) +{ + struct cpufreq_policy new_policy; + int ret = 0; + memcpy(&new_policy, policy, sizeof(struct cpufreq_policy)); /* assure that the starting sequence is run in __cpufreq_set_policy */ policy->governor = NULL; @@ -896,12 +899,6 @@ static int cpufreq_add_dev_interface(unsigned int cpu, if (cpufreq_driver->exit) cpufreq_driver->exit(policy); } - return ret; - -err_out_kobj_put: - kobject_put(&policy->kobj); - wait_for_completion(&policy->kobj_unregister); - return ret; } #ifdef CONFIG_HOTPLUG_CPU @@ -1075,10 +1072,19 @@ static int cpufreq_add_dev(struct device *dev, struct subsys_interface *sif) } #endif + write_lock_irqsave(&cpufreq_driver_lock, flags); + for_each_cpu(j, policy->cpus) { + per_cpu(cpufreq_cpu_data, j) = policy; + per_cpu(cpufreq_policy_cpu, j) = policy->cpu; + } + write_unlock_irqrestore(&cpufreq_driver_lock, flags); + ret = cpufreq_add_dev_interface(cpu, policy, dev); if (ret) goto err_out_unregister; + cpufreq_init_policy(policy); + kobject_uevent(&policy->kobj, KOBJ_ADD); module_put(cpufreq_driver->owner); pr_debug("initialization complete\n"); @@ -1087,8 +1093,11 @@ static int cpufreq_add_dev(struct device *dev, struct subsys_interface *sif) err_out_unregister: write_lock_irqsave(&cpufreq_driver_lock, flags); - for_each_cpu(j, policy->cpus) + for_each_cpu(j, policy->cpus) { per_cpu(cpufreq_cpu_data, j) = NULL; + if (j != cpu) + per_cpu(cpufreq_policy_cpu, j) = -1; + } write_unlock_irqrestore(&cpufreq_driver_lock, flags); kobject_put(&policy->kobj); -- cgit v1.2.3 From f9ba680d23ea7e2fc31b4b7106a482d90ec62a24 Mon Sep 17 00:00:00 2001 From: "Srivatsa S. Bhat" Date: Tue, 30 Jul 2013 04:24:36 +0530 Subject: cpufreq: Extract the handover of policy cpu to a helper function During cpu offline, when the policy->cpu is going down, some other CPU present in the policy->cpus mask is nominated as the new policy->cpu. Extract this functionality from __cpufreq_remove_dev() and implement it in a helper function. This helps in upcoming code reorganization. Signed-off-by: Srivatsa S. Bhat Acked-by: Viresh Kumar Signed-off-by: Rafael J. Wysocki --- drivers/cpufreq/cpufreq.c | 63 +++++++++++++++++++++++++++++------------------ 1 file changed, 39 insertions(+), 24 deletions(-) (limited to 'drivers/cpufreq/cpufreq.c') diff --git a/drivers/cpufreq/cpufreq.c b/drivers/cpufreq/cpufreq.c index f7c58c79217d..0611ae48e767 100644 --- a/drivers/cpufreq/cpufreq.c +++ b/drivers/cpufreq/cpufreq.c @@ -1129,6 +1129,38 @@ static void update_policy_cpu(struct cpufreq_policy *policy, unsigned int cpu) CPUFREQ_UPDATE_POLICY_CPU, policy); } +static int cpufreq_nominate_new_policy_cpu(struct cpufreq_policy *data, + unsigned int old_cpu) +{ + struct device *cpu_dev; + unsigned long flags; + int ret; + + /* first sibling now owns the new sysfs dir */ + cpu_dev = get_cpu_device(cpumask_first(data->cpus)); + sysfs_remove_link(&cpu_dev->kobj, "cpufreq"); + ret = kobject_move(&data->kobj, &cpu_dev->kobj); + if (ret) { + pr_err("%s: Failed to move kobj: %d", __func__, ret); + + WARN_ON(lock_policy_rwsem_write(old_cpu)); + cpumask_set_cpu(old_cpu, data->cpus); + + write_lock_irqsave(&cpufreq_driver_lock, flags); + per_cpu(cpufreq_cpu_data, old_cpu) = data; + write_unlock_irqrestore(&cpufreq_driver_lock, flags); + + unlock_policy_rwsem_write(old_cpu); + + ret = sysfs_create_link(&cpu_dev->kobj, &data->kobj, + "cpufreq"); + + return -EINVAL; + } + + return cpu_dev->id; +} + /** * __cpufreq_remove_dev - remove a CPU device * @@ -1139,12 +1171,12 @@ static void update_policy_cpu(struct cpufreq_policy *policy, unsigned int cpu) static int __cpufreq_remove_dev(struct device *dev, struct subsys_interface *sif) { - unsigned int cpu = dev->id, ret, cpus; + unsigned int cpu = dev->id, cpus; + int new_cpu; unsigned long flags; struct cpufreq_policy *data; struct kobject *kobj; struct completion *cmp; - struct device *cpu_dev; pr_debug("%s: unregistering CPU %u\n", __func__, cpu); @@ -1179,32 +1211,15 @@ static int __cpufreq_remove_dev(struct device *dev, if (cpu != data->cpu) { sysfs_remove_link(&dev->kobj, "cpufreq"); } else if (cpus > 1) { - /* first sibling now owns the new sysfs dir */ - cpu_dev = get_cpu_device(cpumask_first(data->cpus)); - sysfs_remove_link(&cpu_dev->kobj, "cpufreq"); - ret = kobject_move(&data->kobj, &cpu_dev->kobj); - if (ret) { - pr_err("%s: Failed to move kobj: %d", __func__, ret); + new_cpu = cpufreq_nominate_new_policy_cpu(data, cpu); + if (new_cpu >= 0) { WARN_ON(lock_policy_rwsem_write(cpu)); - cpumask_set_cpu(cpu, data->cpus); - - write_lock_irqsave(&cpufreq_driver_lock, flags); - per_cpu(cpufreq_cpu_data, cpu) = data; - write_unlock_irqrestore(&cpufreq_driver_lock, flags); - + update_policy_cpu(data, new_cpu); unlock_policy_rwsem_write(cpu); - - ret = sysfs_create_link(&cpu_dev->kobj, &data->kobj, - "cpufreq"); - return -EINVAL; + pr_debug("%s: policy Kobject moved to cpu: %d " + "from: %d\n",__func__, new_cpu, cpu); } - - WARN_ON(lock_policy_rwsem_write(cpu)); - update_policy_cpu(data, cpu_dev->id); - unlock_policy_rwsem_write(cpu); - pr_debug("%s: policy Kobject moved to cpu: %d from: %d\n", - __func__, cpu_dev->id, cpu); } /* If cpu is last user of policy, free policy */ -- cgit v1.2.3 From a82fab292898f88ea9ca99dd10c1773dcada08b6 Mon Sep 17 00:00:00 2001 From: "Srivatsa S. Bhat" Date: Tue, 30 Jul 2013 04:24:49 +0530 Subject: cpufreq: Introduce a flag ('frozen') to separate full vs temporary init/teardown During suspend/resume we would like to do a light-weight init/teardown of CPUs in the cpufreq subsystem and preserve certain things such as sysfs files etc across suspend/resume transitions. Add a flag called 'frozen' to help distinguish the full init/teardown sequence from the light-weight one. Signed-off-by: Srivatsa S. Bhat Acked-by: Viresh Kumar Signed-off-by: Rafael J. Wysocki --- drivers/cpufreq/cpufreq.c | 76 ++++++++++++++++++++++++++++++----------------- 1 file changed, 49 insertions(+), 27 deletions(-) (limited to 'drivers/cpufreq/cpufreq.c') diff --git a/drivers/cpufreq/cpufreq.c b/drivers/cpufreq/cpufreq.c index 0611ae48e767..1d041aff4d48 100644 --- a/drivers/cpufreq/cpufreq.c +++ b/drivers/cpufreq/cpufreq.c @@ -903,7 +903,7 @@ static void cpufreq_init_policy(struct cpufreq_policy *policy) #ifdef CONFIG_HOTPLUG_CPU static int cpufreq_add_policy_cpu(unsigned int cpu, unsigned int sibling, - struct device *dev) + struct device *dev, bool frozen) { struct cpufreq_policy *policy; int ret = 0, has_target = !!cpufreq_driver->target; @@ -931,13 +931,18 @@ static int cpufreq_add_policy_cpu(unsigned int cpu, unsigned int sibling, __cpufreq_governor(policy, CPUFREQ_GOV_LIMITS); } - ret = sysfs_create_link(&dev->kobj, &policy->kobj, "cpufreq"); - if (ret) { + /* Don't touch sysfs links during light-weight init */ + if (frozen) { + /* Drop the extra refcount that we took above */ cpufreq_cpu_put(policy); - return ret; + return 0; } - return 0; + ret = sysfs_create_link(&dev->kobj, &policy->kobj, "cpufreq"); + if (ret) + cpufreq_cpu_put(policy); + + return ret; } #endif @@ -972,16 +977,8 @@ static void cpufreq_policy_free(struct cpufreq_policy *policy) kfree(policy); } -/** - * cpufreq_add_dev - add a CPU device - * - * Adds the cpufreq interface for a CPU device. - * - * The Oracle says: try running cpufreq registration/unregistration concurrently - * with with cpu hotplugging and all hell will break loose. Tried to clean this - * mess up, but more thorough testing is needed. - Mathieu - */ -static int cpufreq_add_dev(struct device *dev, struct subsys_interface *sif) +static int __cpufreq_add_dev(struct device *dev, struct subsys_interface *sif, + bool frozen) { unsigned int j, cpu = dev->id; int ret = -ENOMEM; @@ -1013,7 +1010,8 @@ static int cpufreq_add_dev(struct device *dev, struct subsys_interface *sif) struct cpufreq_policy *cp = per_cpu(cpufreq_cpu_data, sibling); if (cp && cpumask_test_cpu(cpu, cp->related_cpus)) { read_unlock_irqrestore(&cpufreq_driver_lock, flags); - return cpufreq_add_policy_cpu(cpu, sibling, dev); + return cpufreq_add_policy_cpu(cpu, sibling, dev, + frozen); } } read_unlock_irqrestore(&cpufreq_driver_lock, flags); @@ -1079,9 +1077,11 @@ static int cpufreq_add_dev(struct device *dev, struct subsys_interface *sif) } write_unlock_irqrestore(&cpufreq_driver_lock, flags); - ret = cpufreq_add_dev_interface(cpu, policy, dev); - if (ret) - goto err_out_unregister; + if (!frozen) { + ret = cpufreq_add_dev_interface(cpu, policy, dev); + if (ret) + goto err_out_unregister; + } cpufreq_init_policy(policy); @@ -1112,6 +1112,20 @@ module_out: return ret; } +/** + * cpufreq_add_dev - add a CPU device + * + * Adds the cpufreq interface for a CPU device. + * + * The Oracle says: try running cpufreq registration/unregistration concurrently + * with with cpu hotplugging and all hell will break loose. Tried to clean this + * mess up, but more thorough testing is needed. - Mathieu + */ +static int cpufreq_add_dev(struct device *dev, struct subsys_interface *sif) +{ + return __cpufreq_add_dev(dev, sif, false); +} + static void update_policy_cpu(struct cpufreq_policy *policy, unsigned int cpu) { int j; @@ -1130,7 +1144,7 @@ static void update_policy_cpu(struct cpufreq_policy *policy, unsigned int cpu) } static int cpufreq_nominate_new_policy_cpu(struct cpufreq_policy *data, - unsigned int old_cpu) + unsigned int old_cpu, bool frozen) { struct device *cpu_dev; unsigned long flags; @@ -1138,6 +1152,11 @@ static int cpufreq_nominate_new_policy_cpu(struct cpufreq_policy *data, /* first sibling now owns the new sysfs dir */ cpu_dev = get_cpu_device(cpumask_first(data->cpus)); + + /* Don't touch sysfs files during light-weight tear-down */ + if (frozen) + return cpu_dev->id; + sysfs_remove_link(&cpu_dev->kobj, "cpufreq"); ret = kobject_move(&data->kobj, &cpu_dev->kobj); if (ret) { @@ -1169,7 +1188,7 @@ static int cpufreq_nominate_new_policy_cpu(struct cpufreq_policy *data, * This routine frees the rwsem before returning. */ static int __cpufreq_remove_dev(struct device *dev, - struct subsys_interface *sif) + struct subsys_interface *sif, bool frozen) { unsigned int cpu = dev->id, cpus; int new_cpu; @@ -1208,17 +1227,20 @@ static int __cpufreq_remove_dev(struct device *dev, cpumask_clear_cpu(cpu, data->cpus); unlock_policy_rwsem_write(cpu); - if (cpu != data->cpu) { + if (cpu != data->cpu && !frozen) { sysfs_remove_link(&dev->kobj, "cpufreq"); } else if (cpus > 1) { - new_cpu = cpufreq_nominate_new_policy_cpu(data, cpu); + new_cpu = cpufreq_nominate_new_policy_cpu(data, cpu, frozen); if (new_cpu >= 0) { WARN_ON(lock_policy_rwsem_write(cpu)); update_policy_cpu(data, new_cpu); unlock_policy_rwsem_write(cpu); - pr_debug("%s: policy Kobject moved to cpu: %d " - "from: %d\n",__func__, new_cpu, cpu); + + if (!frozen) { + pr_debug("%s: policy Kobject moved to cpu: %d " + "from: %d\n",__func__, new_cpu, cpu); + } } } @@ -1266,7 +1288,7 @@ static int cpufreq_remove_dev(struct device *dev, struct subsys_interface *sif) if (cpu_is_offline(cpu)) return 0; - retval = __cpufreq_remove_dev(dev, sif); + retval = __cpufreq_remove_dev(dev, sif, false); return retval; } @@ -1992,7 +2014,7 @@ static int cpufreq_cpu_callback(struct notifier_block *nfb, break; case CPU_DOWN_PREPARE: case CPU_DOWN_PREPARE_FROZEN: - __cpufreq_remove_dev(dev, NULL); + __cpufreq_remove_dev(dev, NULL, false); break; case CPU_DOWN_FAILED: case CPU_DOWN_FAILED_FROZEN: -- cgit v1.2.3 From 8414809c6a1e8479e331e09254adb58b33a36d25 Mon Sep 17 00:00:00 2001 From: "Srivatsa S. Bhat" Date: Tue, 30 Jul 2013 04:25:10 +0530 Subject: cpufreq: Preserve policy structure across suspend/resume To perform light-weight cpu-init and teardown in the cpufreq subsystem during suspend/resume, we need to separate out the 2 main functionalities of the cpufreq CPU hotplug callbacks, as outlined below: 1. Init/tear-down of core cpufreq and CPU-specific components, which are critical to the correct functioning of the cpufreq subsystem. 2. Init/tear-down of cpufreq sysfs files during suspend/resume. The first part requires accurate updates to the policy structure such as its ->cpus and ->related_cpus masks, whereas the second part requires that the policy->kobj structure is not released or re-initialized during suspend/resume. To handle both these requirements, we need to allow updates to the policy structure throughout suspend/resume, but prevent the structure from getting freed up. Also, we must have a mechanism by which the cpu-up callbacks can restore the policy structure, without allocating things afresh. (That also helps avoid memory leaks). To achieve this, we use 2 schemes: a. Use a fallback per-cpu storage area for preserving the policy structures during suspend, so that they can be restored during resume appropriately. b. Use the 'frozen' flag to determine when to free or allocate the policy structure vs when to restore the policy from the saved fallback storage. Thus we can successfully preserve the structure across suspend/resume. Effectively, this helps us complete the separation of the 'light-weight' and the 'full' init/tear-down sequences in the cpufreq subsystem, so that this can be made use of in the suspend/resume scenario. Signed-off-by: Srivatsa S. Bhat Acked-by: Viresh Kumar Signed-off-by: Rafael J. Wysocki --- drivers/cpufreq/cpufreq.c | 69 ++++++++++++++++++++++++++++++++++++----------- 1 file changed, 53 insertions(+), 16 deletions(-) (limited to 'drivers/cpufreq/cpufreq.c') diff --git a/drivers/cpufreq/cpufreq.c b/drivers/cpufreq/cpufreq.c index 1d041aff4d48..e0ace3d9382c 100644 --- a/drivers/cpufreq/cpufreq.c +++ b/drivers/cpufreq/cpufreq.c @@ -44,6 +44,7 @@ */ static struct cpufreq_driver *cpufreq_driver; static DEFINE_PER_CPU(struct cpufreq_policy *, cpufreq_cpu_data); +static DEFINE_PER_CPU(struct cpufreq_policy *, cpufreq_cpu_data_fallback); static DEFINE_RWLOCK(cpufreq_driver_lock); static DEFINE_MUTEX(cpufreq_governor_lock); @@ -946,6 +947,20 @@ static int cpufreq_add_policy_cpu(unsigned int cpu, unsigned int sibling, } #endif +static struct cpufreq_policy *cpufreq_policy_restore(unsigned int cpu) +{ + struct cpufreq_policy *policy; + unsigned long flags; + + write_lock_irqsave(&cpufreq_driver_lock, flags); + + policy = per_cpu(cpufreq_cpu_data_fallback, cpu); + + write_unlock_irqrestore(&cpufreq_driver_lock, flags); + + return policy; +} + static struct cpufreq_policy *cpufreq_policy_alloc(void) { struct cpufreq_policy *policy; @@ -1023,7 +1038,12 @@ static int __cpufreq_add_dev(struct device *dev, struct subsys_interface *sif, goto module_out; } - policy = cpufreq_policy_alloc(); + if (frozen) + /* Restore the saved policy when doing light-weight init */ + policy = cpufreq_policy_restore(cpu); + else + policy = cpufreq_policy_alloc(); + if (!policy) goto nomem_out; @@ -1204,6 +1224,10 @@ static int __cpufreq_remove_dev(struct device *dev, data = per_cpu(cpufreq_cpu_data, cpu); per_cpu(cpufreq_cpu_data, cpu) = NULL; + /* Save the policy somewhere when doing a light-weight tear-down */ + if (frozen) + per_cpu(cpufreq_cpu_data_fallback, cpu) = data; + write_unlock_irqrestore(&cpufreq_driver_lock, flags); if (!data) { @@ -1249,27 +1273,40 @@ static int __cpufreq_remove_dev(struct device *dev, if (cpufreq_driver->target) __cpufreq_governor(data, CPUFREQ_GOV_POLICY_EXIT); - lock_policy_rwsem_read(cpu); - kobj = &data->kobj; - cmp = &data->kobj_unregister; - unlock_policy_rwsem_read(cpu); - kobject_put(kobj); + if (!frozen) { + lock_policy_rwsem_read(cpu); + kobj = &data->kobj; + cmp = &data->kobj_unregister; + unlock_policy_rwsem_read(cpu); + kobject_put(kobj); + + /* + * We need to make sure that the underlying kobj is + * actually not referenced anymore by anybody before we + * proceed with unloading. + */ + pr_debug("waiting for dropping of refcount\n"); + wait_for_completion(cmp); + pr_debug("wait complete\n"); + } - /* we need to make sure that the underlying kobj is actually - * not referenced anymore by anybody before we proceed with - * unloading. + /* + * Perform the ->exit() even during light-weight tear-down, + * since this is a core component, and is essential for the + * subsequent light-weight ->init() to succeed. */ - pr_debug("waiting for dropping of refcount\n"); - wait_for_completion(cmp); - pr_debug("wait complete\n"); - if (cpufreq_driver->exit) cpufreq_driver->exit(data); - cpufreq_policy_free(data); + if (!frozen) + cpufreq_policy_free(data); } else { - pr_debug("%s: removing link, cpu: %d\n", __func__, cpu); - cpufreq_cpu_put(data); + + if (!frozen) { + pr_debug("%s: removing link, cpu: %d\n", __func__, cpu); + cpufreq_cpu_put(data); + } + if (cpufreq_driver->target) { __cpufreq_governor(data, CPUFREQ_GOV_START); __cpufreq_governor(data, CPUFREQ_GOV_LIMITS); -- cgit v1.2.3 From 5302c3fb2e62f4ca5e43e060491ba299f58c5231 Mon Sep 17 00:00:00 2001 From: "Srivatsa S. Bhat" Date: Tue, 30 Jul 2013 04:25:25 +0530 Subject: cpufreq: Perform light-weight init/teardown during suspend/resume Now that we have the infrastructure to perform a light-weight init/tear-down, use that in the cpufreq CPU hotplug notifier when invoked from the suspend/resume path. This also ensures that the file permissions of the cpufreq sysfs files are preserved across suspend/resume, something which commit a66b2e (cpufreq: Preserve sysfs files across suspend/resume) originally intended to do, but had to be reverted due to other problems. Signed-off-by: Srivatsa S. Bhat Acked-by: Viresh Kumar Signed-off-by: Rafael J. Wysocki --- drivers/cpufreq/cpufreq.c | 18 +++++++++++------- 1 file changed, 11 insertions(+), 7 deletions(-) (limited to 'drivers/cpufreq/cpufreq.c') diff --git a/drivers/cpufreq/cpufreq.c b/drivers/cpufreq/cpufreq.c index e0ace3d9382c..370abb66babc 100644 --- a/drivers/cpufreq/cpufreq.c +++ b/drivers/cpufreq/cpufreq.c @@ -2040,22 +2040,26 @@ static int cpufreq_cpu_callback(struct notifier_block *nfb, { unsigned int cpu = (unsigned long)hcpu; struct device *dev; + bool frozen = false; dev = get_cpu_device(cpu); if (dev) { - switch (action) { + + if (action & CPU_TASKS_FROZEN) + frozen = true; + + switch (action & ~CPU_TASKS_FROZEN) { case CPU_ONLINE: - case CPU_ONLINE_FROZEN: - cpufreq_add_dev(dev, NULL); + __cpufreq_add_dev(dev, NULL, frozen); cpufreq_update_policy(cpu); break; + case CPU_DOWN_PREPARE: - case CPU_DOWN_PREPARE_FROZEN: - __cpufreq_remove_dev(dev, NULL, false); + __cpufreq_remove_dev(dev, NULL, frozen); break; + case CPU_DOWN_FAILED: - case CPU_DOWN_FAILED_FROZEN: - cpufreq_add_dev(dev, NULL); + __cpufreq_add_dev(dev, NULL, frozen); break; } } -- cgit v1.2.3 From e8fdde1011ea45792e60f14f620b01f78cb0d34d Mon Sep 17 00:00:00 2001 From: Viresh Kumar Date: Wed, 31 Jul 2013 14:31:33 +0200 Subject: cpufreq: Remove extra variables from cpufreq_add_dev_symlink() We call cpufreq_cpu_get() in cpufreq_add_dev_symlink() to increase usage refcount of policy, but not to get a policy for the given CPU. So, we don't really need to capture the return value of this routine. We can simply use policy passed as an argument to cpufreq_add_dev_symlink(). Moreover debug print is rewritten to make it more clear. [rjw: Changelog] Signed-off-by: Viresh Kumar Signed-off-by: Rafael J. Wysocki --- drivers/cpufreq/cpufreq.c | 7 +++---- 1 file changed, 3 insertions(+), 4 deletions(-) (limited to 'drivers/cpufreq/cpufreq.c') diff --git a/drivers/cpufreq/cpufreq.c b/drivers/cpufreq/cpufreq.c index 370abb66babc..b6154ca1f896 100644 --- a/drivers/cpufreq/cpufreq.c +++ b/drivers/cpufreq/cpufreq.c @@ -813,19 +813,18 @@ static int cpufreq_add_dev_symlink(unsigned int cpu, int ret = 0; for_each_cpu(j, policy->cpus) { - struct cpufreq_policy *managed_policy; struct device *cpu_dev; if (j == cpu) continue; - pr_debug("CPU %u already managed, adding link\n", j); - managed_policy = cpufreq_cpu_get(cpu); + pr_debug("Adding link for CPU: %u\n", j); + cpufreq_cpu_get(cpu); cpu_dev = get_cpu_device(j); ret = sysfs_create_link(&cpu_dev->kobj, &policy->kobj, "cpufreq"); if (ret) { - cpufreq_cpu_put(managed_policy); + cpufreq_cpu_put(policy); return ret; } } -- cgit v1.2.3 From 308b60e71541518f3fe97171b4daf71adc607f3d Mon Sep 17 00:00:00 2001 From: Viresh Kumar Date: Wed, 31 Jul 2013 14:35:14 +0200 Subject: cpufreq: Don't pass CPU to cpufreq_add_dev_{symlink|interface}() Pointer to struct cpufreq_policy is already passed to these routines and we don't need to send policy->cpu to them as well. So, get rid of this extra argument and use policy->cpu everywhere. Signed-off-by: Viresh Kumar Signed-off-by: Rafael J. Wysocki --- drivers/cpufreq/cpufreq.c | 14 ++++++-------- 1 file changed, 6 insertions(+), 8 deletions(-) (limited to 'drivers/cpufreq/cpufreq.c') diff --git a/drivers/cpufreq/cpufreq.c b/drivers/cpufreq/cpufreq.c index b6154ca1f896..576b312645a5 100644 --- a/drivers/cpufreq/cpufreq.c +++ b/drivers/cpufreq/cpufreq.c @@ -806,8 +806,7 @@ void cpufreq_sysfs_remove_file(const struct attribute *attr) EXPORT_SYMBOL(cpufreq_sysfs_remove_file); /* symlink affected CPUs */ -static int cpufreq_add_dev_symlink(unsigned int cpu, - struct cpufreq_policy *policy) +static int cpufreq_add_dev_symlink(struct cpufreq_policy *policy) { unsigned int j; int ret = 0; @@ -815,11 +814,11 @@ static int cpufreq_add_dev_symlink(unsigned int cpu, for_each_cpu(j, policy->cpus) { struct device *cpu_dev; - if (j == cpu) + if (j == policy->cpu) continue; pr_debug("Adding link for CPU: %u\n", j); - cpufreq_cpu_get(cpu); + cpufreq_cpu_get(policy->cpu); cpu_dev = get_cpu_device(j); ret = sysfs_create_link(&cpu_dev->kobj, &policy->kobj, "cpufreq"); @@ -831,8 +830,7 @@ static int cpufreq_add_dev_symlink(unsigned int cpu, return ret; } -static int cpufreq_add_dev_interface(unsigned int cpu, - struct cpufreq_policy *policy, +static int cpufreq_add_dev_interface(struct cpufreq_policy *policy, struct device *dev) { struct freq_attr **drv_attr; @@ -868,7 +866,7 @@ static int cpufreq_add_dev_interface(unsigned int cpu, goto err_out_kobj_put; } - ret = cpufreq_add_dev_symlink(cpu, policy); + ret = cpufreq_add_dev_symlink(policy); if (ret) goto err_out_kobj_put; @@ -1097,7 +1095,7 @@ static int __cpufreq_add_dev(struct device *dev, struct subsys_interface *sif, write_unlock_irqrestore(&cpufreq_driver_lock, flags); if (!frozen) { - ret = cpufreq_add_dev_interface(cpu, policy, dev); + ret = cpufreq_add_dev_interface(policy, dev); if (ret) goto err_out_unregister; } -- cgit v1.2.3 From 71c3461ef7c67024792d283b88630245a6c169ba Mon Sep 17 00:00:00 2001 From: "Rafael J. Wysocki" Date: Sun, 4 Aug 2013 01:19:34 +0200 Subject: cpufreq: Do not hold driver module references for additional policy CPUs The cpufreq core is a little inconsistent in the way it uses the driver module refcount. Namely, if __cpufreq_add_dev() is called for a CPU that doesn't share the policy object with any other CPUs, the driver module refcount it grabs to start with will be dropped by it before returning and will be equal to whatever it had been before that function was invoked. However, if the given CPU does share the policy object with other CPUs, either cpufreq_add_policy_cpu() is called to link the new CPU to the existing policy, or cpufreq_add_dev_symlink() is used to link the other CPUs sharing the policy with it to the just created policy object. In that case, because both cpufreq_add_policy_cpu() and cpufreq_add_dev_symlink() call cpufreq_cpu_get() for the given policy (the latter possibly many times) without the balancing cpufreq_cpu_put() (unless there is an error), the driver module refcount will be left by __cpufreq_add_dev() with a nonzero value (different from the initial one). To remove that inconsistency make cpufreq_add_policy_cpu() execute cpufreq_cpu_put() for the given policy before returning, which decrements the driver module refcount so that it will be equal to its initial value after __cpufreq_add_dev() returns. Also remove the cpufreq_cpu_get() call from cpufreq_add_dev_symlink(), since both the policy refcount and the driver module refcount are nonzero when it is called and they don't need to be bumped up by it. Accordingly, drop the cpufreq_cpu_put() from __cpufreq_remove_dev(), since it is only necessary to balance the cpufreq_cpu_get() called by cpufreq_add_policy_cpu() or cpufreq_add_dev_symlink(). Signed-off-by: Rafael J. Wysocki Reviewed-by: Srivatsa S. Bhat Acked-by: Viresh Kumar --- drivers/cpufreq/cpufreq.c | 28 +++++++--------------------- 1 file changed, 7 insertions(+), 21 deletions(-) (limited to 'drivers/cpufreq/cpufreq.c') diff --git a/drivers/cpufreq/cpufreq.c b/drivers/cpufreq/cpufreq.c index 576b312645a5..c8b2ca0f44ae 100644 --- a/drivers/cpufreq/cpufreq.c +++ b/drivers/cpufreq/cpufreq.c @@ -818,14 +818,11 @@ static int cpufreq_add_dev_symlink(struct cpufreq_policy *policy) continue; pr_debug("Adding link for CPU: %u\n", j); - cpufreq_cpu_get(policy->cpu); cpu_dev = get_cpu_device(j); ret = sysfs_create_link(&cpu_dev->kobj, &policy->kobj, "cpufreq"); - if (ret) { - cpufreq_cpu_put(policy); - return ret; - } + if (ret) + break; } return ret; } @@ -908,7 +905,8 @@ static int cpufreq_add_policy_cpu(unsigned int cpu, unsigned int sibling, unsigned long flags; policy = cpufreq_cpu_get(sibling); - WARN_ON(!policy); + if (WARN_ON_ONCE(!policy)) + return -ENODATA; if (has_target) __cpufreq_governor(policy, CPUFREQ_GOV_STOP); @@ -930,16 +928,10 @@ static int cpufreq_add_policy_cpu(unsigned int cpu, unsigned int sibling, } /* Don't touch sysfs links during light-weight init */ - if (frozen) { - /* Drop the extra refcount that we took above */ - cpufreq_cpu_put(policy); - return 0; - } - - ret = sysfs_create_link(&dev->kobj, &policy->kobj, "cpufreq"); - if (ret) - cpufreq_cpu_put(policy); + if (!frozen) + ret = sysfs_create_link(&dev->kobj, &policy->kobj, "cpufreq"); + cpufreq_cpu_put(policy); return ret; } #endif @@ -1298,12 +1290,6 @@ static int __cpufreq_remove_dev(struct device *dev, if (!frozen) cpufreq_policy_free(data); } else { - - if (!frozen) { - pr_debug("%s: removing link, cpu: %d\n", __func__, cpu); - cpufreq_cpu_put(data); - } - if (cpufreq_driver->target) { __cpufreq_governor(data, CPUFREQ_GOV_START); __cpufreq_governor(data, CPUFREQ_GOV_LIMITS); -- cgit v1.2.3 From 10659ab7b50e963429f1a681882404ca37aa584c Mon Sep 17 00:00:00 2001 From: "Rafael J. Wysocki" Date: Sun, 4 Aug 2013 01:19:41 +0200 Subject: cpufreq: Avoid double kobject_put() for the same kobject in error code path The only case triggering a jump to the err_out_unregister label in __cpufreq_add_dev() is when cpufreq_add_dev_interface() fails. However, if cpufreq_add_dev_interface() fails, it calls kobject_put() for the policy kobject in its error code path and since that causes the kobject's refcount to become 0, the additional kobject_put() for the same kobject under err_out_unregister and the wait_for_completion() following it are pointless, so drop them. Signed-off-by: Rafael J. Wysocki Reviewed-by: Srivatsa S. Bhat Acked-by: Viresh Kumar --- drivers/cpufreq/cpufreq.c | 3 --- 1 file changed, 3 deletions(-) (limited to 'drivers/cpufreq/cpufreq.c') diff --git a/drivers/cpufreq/cpufreq.c b/drivers/cpufreq/cpufreq.c index c8b2ca0f44ae..924d3f5df26d 100644 --- a/drivers/cpufreq/cpufreq.c +++ b/drivers/cpufreq/cpufreq.c @@ -1109,9 +1109,6 @@ err_out_unregister: } write_unlock_irqrestore(&cpufreq_driver_lock, flags); - kobject_put(&policy->kobj); - wait_for_completion(&policy->kobj_unregister); - err_set_policy_cpu: per_cpu(cpufreq_policy_cpu, cpu) = -1; cpufreq_policy_free(policy); -- cgit v1.2.3 From d8d3b4711297e101bbad826474013edbe342c333 Mon Sep 17 00:00:00 2001 From: Viresh Kumar Date: Sun, 4 Aug 2013 01:20:07 +0200 Subject: cpufreq: Pass policy to cpufreq_add_policy_cpu() The caller of cpufreq_add_policy_cpu() already has a pointer to the policy structure and there is no need to look it up again in cpufreq_add_policy_cpu(). Let's pass it directly. Signed-off-by: Viresh Kumar Reviewed-by: Srivatsa S. Bhat Signed-off-by: Rafael J. Wysocki --- drivers/cpufreq/cpufreq.c | 18 ++++++------------ 1 file changed, 6 insertions(+), 12 deletions(-) (limited to 'drivers/cpufreq/cpufreq.c') diff --git a/drivers/cpufreq/cpufreq.c b/drivers/cpufreq/cpufreq.c index 924d3f5df26d..1faf320a5038 100644 --- a/drivers/cpufreq/cpufreq.c +++ b/drivers/cpufreq/cpufreq.c @@ -897,21 +897,17 @@ static void cpufreq_init_policy(struct cpufreq_policy *policy) } #ifdef CONFIG_HOTPLUG_CPU -static int cpufreq_add_policy_cpu(unsigned int cpu, unsigned int sibling, - struct device *dev, bool frozen) +static int cpufreq_add_policy_cpu(struct cpufreq_policy *policy, + unsigned int cpu, struct device *dev, + bool frozen) { - struct cpufreq_policy *policy; int ret = 0, has_target = !!cpufreq_driver->target; unsigned long flags; - policy = cpufreq_cpu_get(sibling); - if (WARN_ON_ONCE(!policy)) - return -ENODATA; - if (has_target) __cpufreq_governor(policy, CPUFREQ_GOV_STOP); - lock_policy_rwsem_write(sibling); + lock_policy_rwsem_write(policy->cpu); write_lock_irqsave(&cpufreq_driver_lock, flags); @@ -920,7 +916,7 @@ static int cpufreq_add_policy_cpu(unsigned int cpu, unsigned int sibling, per_cpu(cpufreq_cpu_data, cpu) = policy; write_unlock_irqrestore(&cpufreq_driver_lock, flags); - unlock_policy_rwsem_write(sibling); + unlock_policy_rwsem_write(policy->cpu); if (has_target) { __cpufreq_governor(policy, CPUFREQ_GOV_START); @@ -931,7 +927,6 @@ static int cpufreq_add_policy_cpu(unsigned int cpu, unsigned int sibling, if (!frozen) ret = sysfs_create_link(&dev->kobj, &policy->kobj, "cpufreq"); - cpufreq_cpu_put(policy); return ret; } #endif @@ -1014,8 +1009,7 @@ static int __cpufreq_add_dev(struct device *dev, struct subsys_interface *sif, struct cpufreq_policy *cp = per_cpu(cpufreq_cpu_data, sibling); if (cp && cpumask_test_cpu(cpu, cp->related_cpus)) { read_unlock_irqrestore(&cpufreq_driver_lock, flags); - return cpufreq_add_policy_cpu(cpu, sibling, dev, - frozen); + return cpufreq_add_policy_cpu(cp, cpu, dev, frozen); } } read_unlock_irqrestore(&cpufreq_driver_lock, flags); -- cgit v1.2.3 From 5ff0a268037d344f86df690ccb994d8bc015d2d9 Mon Sep 17 00:00:00 2001 From: Viresh Kumar Date: Tue, 6 Aug 2013 22:53:03 +0530 Subject: cpufreq: Clean up header files included in the core This patch addresses the following issues in the header files in the cpufreq core: - Include headers in ascending order, so that we don't add same many times by mistake. - must be included after , so that they override whatever they need to. - Remove unnecessary includes. - Don't include files already included by cpufreq.h or cpufreq_governor.h. [rjw: Changelog] Signed-off-by: Viresh Kumar Signed-off-by: Rafael J. Wysocki --- drivers/cpufreq/cpufreq.c | 19 ++++++------------- 1 file changed, 6 insertions(+), 13 deletions(-) (limited to 'drivers/cpufreq/cpufreq.c') diff --git a/drivers/cpufreq/cpufreq.c b/drivers/cpufreq/cpufreq.c index e34bd94e12b4..845837174878 100644 --- a/drivers/cpufreq/cpufreq.c +++ b/drivers/cpufreq/cpufreq.c @@ -17,24 +17,17 @@ #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt -#include -#include -#include -#include -#include -#include +#include #include #include -#include -#include -#include #include -#include -#include -#include +#include +#include +#include #include +#include #include - +#include #include /** -- cgit v1.2.3 From 3a3e9e06d0c11b8efa95933a88c9e67209fa4330 Mon Sep 17 00:00:00 2001 From: Viresh Kumar Date: Tue, 6 Aug 2013 22:53:05 +0530 Subject: cpufreq: Give consistent names to cpufreq_policy objects They are called policy, cur_policy, new_policy, data, etc. Just call them policy wherever possible. Signed-off-by: Viresh Kumar Signed-off-by: Rafael J. Wysocki --- drivers/cpufreq/cpufreq.c | 200 +++++++++++++++++++++++----------------------- 1 file changed, 100 insertions(+), 100 deletions(-) (limited to 'drivers/cpufreq/cpufreq.c') diff --git a/drivers/cpufreq/cpufreq.c b/drivers/cpufreq/cpufreq.c index 845837174878..1793fe82595d 100644 --- a/drivers/cpufreq/cpufreq.c +++ b/drivers/cpufreq/cpufreq.c @@ -179,7 +179,7 @@ EXPORT_SYMBOL_GPL(get_cpu_idle_time); static struct cpufreq_policy *__cpufreq_cpu_get(unsigned int cpu, bool sysfs) { - struct cpufreq_policy *data; + struct cpufreq_policy *policy; unsigned long flags; if (cpu >= nr_cpu_ids) @@ -195,16 +195,16 @@ static struct cpufreq_policy *__cpufreq_cpu_get(unsigned int cpu, bool sysfs) goto err_out_unlock; /* get the CPU */ - data = per_cpu(cpufreq_cpu_data, cpu); + policy = per_cpu(cpufreq_cpu_data, cpu); - if (!data) + if (!policy) goto err_out_put_module; - if (!sysfs && !kobject_get(&data->kobj)) + if (!sysfs && !kobject_get(&policy->kobj)) goto err_out_put_module; read_unlock_irqrestore(&cpufreq_driver_lock, flags); - return data; + return policy; err_out_put_module: module_put(cpufreq_driver->owner); @@ -228,25 +228,25 @@ static struct cpufreq_policy *cpufreq_cpu_get_sysfs(unsigned int cpu) return __cpufreq_cpu_get(cpu, true); } -static void __cpufreq_cpu_put(struct cpufreq_policy *data, bool sysfs) +static void __cpufreq_cpu_put(struct cpufreq_policy *policy, bool sysfs) { if (!sysfs) - kobject_put(&data->kobj); + kobject_put(&policy->kobj); module_put(cpufreq_driver->owner); } -void cpufreq_cpu_put(struct cpufreq_policy *data) +void cpufreq_cpu_put(struct cpufreq_policy *policy) { if (cpufreq_disabled()) return; - __cpufreq_cpu_put(data, false); + __cpufreq_cpu_put(policy, false); } EXPORT_SYMBOL_GPL(cpufreq_cpu_put); -static void cpufreq_cpu_put_sysfs(struct cpufreq_policy *data) +static void cpufreq_cpu_put_sysfs(struct cpufreq_policy *policy) { - __cpufreq_cpu_put(data, true); + __cpufreq_cpu_put(policy, true); } /********************************************************************* @@ -453,8 +453,8 @@ show_one(scaling_min_freq, min); show_one(scaling_max_freq, max); show_one(scaling_cur_freq, cur); -static int __cpufreq_set_policy(struct cpufreq_policy *data, - struct cpufreq_policy *policy); +static int __cpufreq_set_policy(struct cpufreq_policy *policy, + struct cpufreq_policy *new_policy); /** * cpufreq_per_cpu_attr_write() / store_##file_name() - sysfs write access @@ -1136,7 +1136,7 @@ static void update_policy_cpu(struct cpufreq_policy *policy, unsigned int cpu) CPUFREQ_UPDATE_POLICY_CPU, policy); } -static int cpufreq_nominate_new_policy_cpu(struct cpufreq_policy *data, +static int cpufreq_nominate_new_policy_cpu(struct cpufreq_policy *policy, unsigned int old_cpu, bool frozen) { struct device *cpu_dev; @@ -1144,27 +1144,27 @@ static int cpufreq_nominate_new_policy_cpu(struct cpufreq_policy *data, int ret; /* first sibling now owns the new sysfs dir */ - cpu_dev = get_cpu_device(cpumask_first(data->cpus)); + cpu_dev = get_cpu_device(cpumask_first(policy->cpus)); /* Don't touch sysfs files during light-weight tear-down */ if (frozen) return cpu_dev->id; sysfs_remove_link(&cpu_dev->kobj, "cpufreq"); - ret = kobject_move(&data->kobj, &cpu_dev->kobj); + ret = kobject_move(&policy->kobj, &cpu_dev->kobj); if (ret) { pr_err("%s: Failed to move kobj: %d", __func__, ret); WARN_ON(lock_policy_rwsem_write(old_cpu)); - cpumask_set_cpu(old_cpu, data->cpus); + cpumask_set_cpu(old_cpu, policy->cpus); write_lock_irqsave(&cpufreq_driver_lock, flags); - per_cpu(cpufreq_cpu_data, old_cpu) = data; + per_cpu(cpufreq_cpu_data, old_cpu) = policy; write_unlock_irqrestore(&cpufreq_driver_lock, flags); unlock_policy_rwsem_write(old_cpu); - ret = sysfs_create_link(&cpu_dev->kobj, &data->kobj, + ret = sysfs_create_link(&cpu_dev->kobj, &policy->kobj, "cpufreq"); return -EINVAL; @@ -1186,7 +1186,7 @@ static int __cpufreq_remove_dev(struct device *dev, unsigned int cpu = dev->id, cpus; int new_cpu; unsigned long flags; - struct cpufreq_policy *data; + struct cpufreq_policy *policy; struct kobject *kobj; struct completion *cmp; @@ -1194,44 +1194,44 @@ static int __cpufreq_remove_dev(struct device *dev, write_lock_irqsave(&cpufreq_driver_lock, flags); - data = per_cpu(cpufreq_cpu_data, cpu); + policy = per_cpu(cpufreq_cpu_data, cpu); per_cpu(cpufreq_cpu_data, cpu) = NULL; /* Save the policy somewhere when doing a light-weight tear-down */ if (frozen) - per_cpu(cpufreq_cpu_data_fallback, cpu) = data; + per_cpu(cpufreq_cpu_data_fallback, cpu) = policy; write_unlock_irqrestore(&cpufreq_driver_lock, flags); - if (!data) { + if (!policy) { pr_debug("%s: No cpu_data found\n", __func__); return -EINVAL; } if (cpufreq_driver->target) - __cpufreq_governor(data, CPUFREQ_GOV_STOP); + __cpufreq_governor(policy, CPUFREQ_GOV_STOP); #ifdef CONFIG_HOTPLUG_CPU if (!cpufreq_driver->setpolicy) strncpy(per_cpu(cpufreq_cpu_governor, cpu), - data->governor->name, CPUFREQ_NAME_LEN); + policy->governor->name, CPUFREQ_NAME_LEN); #endif WARN_ON(lock_policy_rwsem_write(cpu)); - cpus = cpumask_weight(data->cpus); + cpus = cpumask_weight(policy->cpus); if (cpus > 1) - cpumask_clear_cpu(cpu, data->cpus); + cpumask_clear_cpu(cpu, policy->cpus); unlock_policy_rwsem_write(cpu); - if (cpu != data->cpu && !frozen) { + if (cpu != policy->cpu && !frozen) { sysfs_remove_link(&dev->kobj, "cpufreq"); } else if (cpus > 1) { - new_cpu = cpufreq_nominate_new_policy_cpu(data, cpu, frozen); + new_cpu = cpufreq_nominate_new_policy_cpu(policy, cpu, frozen); if (new_cpu >= 0) { WARN_ON(lock_policy_rwsem_write(cpu)); - update_policy_cpu(data, new_cpu); + update_policy_cpu(policy, new_cpu); unlock_policy_rwsem_write(cpu); if (!frozen) { @@ -1244,12 +1244,12 @@ static int __cpufreq_remove_dev(struct device *dev, /* If cpu is last user of policy, free policy */ if (cpus == 1) { if (cpufreq_driver->target) - __cpufreq_governor(data, CPUFREQ_GOV_POLICY_EXIT); + __cpufreq_governor(policy, CPUFREQ_GOV_POLICY_EXIT); if (!frozen) { lock_policy_rwsem_read(cpu); - kobj = &data->kobj; - cmp = &data->kobj_unregister; + kobj = &policy->kobj; + cmp = &policy->kobj_unregister; unlock_policy_rwsem_read(cpu); kobject_put(kobj); @@ -1269,14 +1269,14 @@ static int __cpufreq_remove_dev(struct device *dev, * subsequent light-weight ->init() to succeed. */ if (cpufreq_driver->exit) - cpufreq_driver->exit(data); + cpufreq_driver->exit(policy); if (!frozen) - cpufreq_policy_free(data); + cpufreq_policy_free(policy); } else { if (cpufreq_driver->target) { - __cpufreq_governor(data, CPUFREQ_GOV_START); - __cpufreq_governor(data, CPUFREQ_GOV_LIMITS); + __cpufreq_governor(policy, CPUFREQ_GOV_START); + __cpufreq_governor(policy, CPUFREQ_GOV_LIMITS); } } @@ -1450,23 +1450,23 @@ static int cpufreq_bp_suspend(void) int ret = 0; int cpu = smp_processor_id(); - struct cpufreq_policy *cpu_policy; + struct cpufreq_policy *policy; pr_debug("suspending cpu %u\n", cpu); /* If there's no policy for the boot CPU, we have nothing to do. */ - cpu_policy = cpufreq_cpu_get(cpu); - if (!cpu_policy) + policy = cpufreq_cpu_get(cpu); + if (!policy) return 0; if (cpufreq_driver->suspend) { - ret = cpufreq_driver->suspend(cpu_policy); + ret = cpufreq_driver->suspend(policy); if (ret) printk(KERN_ERR "cpufreq: suspend failed in ->suspend " - "step on CPU %u\n", cpu_policy->cpu); + "step on CPU %u\n", policy->cpu); } - cpufreq_cpu_put(cpu_policy); + cpufreq_cpu_put(policy); return ret; } @@ -1488,28 +1488,28 @@ static void cpufreq_bp_resume(void) int ret = 0; int cpu = smp_processor_id(); - struct cpufreq_policy *cpu_policy; + struct cpufreq_policy *policy; pr_debug("resuming cpu %u\n", cpu); /* If there's no policy for the boot CPU, we have nothing to do. */ - cpu_policy = cpufreq_cpu_get(cpu); - if (!cpu_policy) + policy = cpufreq_cpu_get(cpu); + if (!policy) return; if (cpufreq_driver->resume) { - ret = cpufreq_driver->resume(cpu_policy); + ret = cpufreq_driver->resume(policy); if (ret) { printk(KERN_ERR "cpufreq: resume failed in ->resume " - "step on CPU %u\n", cpu_policy->cpu); + "step on CPU %u\n", policy->cpu); goto fail; } } - schedule_work(&cpu_policy->update); + schedule_work(&policy->update); fail: - cpufreq_cpu_put(cpu_policy); + cpufreq_cpu_put(policy); } static struct syscore_ops cpufreq_syscore_ops = { @@ -1829,95 +1829,95 @@ EXPORT_SYMBOL(cpufreq_get_policy); * data : current policy. * policy : policy to be set. */ -static int __cpufreq_set_policy(struct cpufreq_policy *data, - struct cpufreq_policy *policy) +static int __cpufreq_set_policy(struct cpufreq_policy *policy, + struct cpufreq_policy *new_policy) { int ret = 0, failed = 1; - pr_debug("setting new policy for CPU %u: %u - %u kHz\n", policy->cpu, - policy->min, policy->max); + pr_debug("setting new policy for CPU %u: %u - %u kHz\n", new_policy->cpu, + new_policy->min, new_policy->max); - memcpy(&policy->cpuinfo, &data->cpuinfo, + memcpy(&new_policy->cpuinfo, &policy->cpuinfo, sizeof(struct cpufreq_cpuinfo)); - if (policy->min > data->max || policy->max < data->min) { + if (new_policy->min > policy->max || new_policy->max < policy->min) { ret = -EINVAL; goto error_out; } /* verify the cpu speed can be set within this limit */ - ret = cpufreq_driver->verify(policy); + ret = cpufreq_driver->verify(new_policy); if (ret) goto error_out; /* adjust if necessary - all reasons */ blocking_notifier_call_chain(&cpufreq_policy_notifier_list, - CPUFREQ_ADJUST, policy); + CPUFREQ_ADJUST, new_policy); /* adjust if necessary - hardware incompatibility*/ blocking_notifier_call_chain(&cpufreq_policy_notifier_list, - CPUFREQ_INCOMPATIBLE, policy); + CPUFREQ_INCOMPATIBLE, new_policy); /* * verify the cpu speed can be set within this limit, which might be * different to the first one */ - ret = cpufreq_driver->verify(policy); + ret = cpufreq_driver->verify(new_policy); if (ret) goto error_out; /* notification of the new policy */ blocking_notifier_call_chain(&cpufreq_policy_notifier_list, - CPUFREQ_NOTIFY, policy); + CPUFREQ_NOTIFY, new_policy); - data->min = policy->min; - data->max = policy->max; + policy->min = new_policy->min; + policy->max = new_policy->max; pr_debug("new min and max freqs are %u - %u kHz\n", - data->min, data->max); + policy->min, policy->max); if (cpufreq_driver->setpolicy) { - data->policy = policy->policy; + policy->policy = new_policy->policy; pr_debug("setting range\n"); - ret = cpufreq_driver->setpolicy(policy); + ret = cpufreq_driver->setpolicy(new_policy); } else { - if (policy->governor != data->governor) { + if (new_policy->governor != policy->governor) { /* save old, working values */ - struct cpufreq_governor *old_gov = data->governor; + struct cpufreq_governor *old_gov = policy->governor; pr_debug("governor switch\n"); /* end old governor */ - if (data->governor) { - __cpufreq_governor(data, CPUFREQ_GOV_STOP); - unlock_policy_rwsem_write(policy->cpu); - __cpufreq_governor(data, + if (policy->governor) { + __cpufreq_governor(policy, CPUFREQ_GOV_STOP); + unlock_policy_rwsem_write(new_policy->cpu); + __cpufreq_governor(policy, CPUFREQ_GOV_POLICY_EXIT); - lock_policy_rwsem_write(policy->cpu); + lock_policy_rwsem_write(new_policy->cpu); } /* start new governor */ - data->governor = policy->governor; - if (!__cpufreq_governor(data, CPUFREQ_GOV_POLICY_INIT)) { - if (!__cpufreq_governor(data, CPUFREQ_GOV_START)) { + policy->governor = new_policy->governor; + if (!__cpufreq_governor(policy, CPUFREQ_GOV_POLICY_INIT)) { + if (!__cpufreq_governor(policy, CPUFREQ_GOV_START)) { failed = 0; } else { - unlock_policy_rwsem_write(policy->cpu); - __cpufreq_governor(data, + unlock_policy_rwsem_write(new_policy->cpu); + __cpufreq_governor(policy, CPUFREQ_GOV_POLICY_EXIT); - lock_policy_rwsem_write(policy->cpu); + lock_policy_rwsem_write(new_policy->cpu); } } if (failed) { /* new governor failed, so re-start old one */ pr_debug("starting governor %s failed\n", - data->governor->name); + policy->governor->name); if (old_gov) { - data->governor = old_gov; - __cpufreq_governor(data, + policy->governor = old_gov; + __cpufreq_governor(policy, CPUFREQ_GOV_POLICY_INIT); - __cpufreq_governor(data, + __cpufreq_governor(policy, CPUFREQ_GOV_START); } ret = -EINVAL; @@ -1926,7 +1926,7 @@ static int __cpufreq_set_policy(struct cpufreq_policy *data, /* might be a policy change, too, so fall through */ } pr_debug("governor: change or update limits\n"); - __cpufreq_governor(data, CPUFREQ_GOV_LIMITS); + __cpufreq_governor(policy, CPUFREQ_GOV_LIMITS); } error_out: @@ -1942,11 +1942,11 @@ error_out: */ int cpufreq_update_policy(unsigned int cpu) { - struct cpufreq_policy *data = cpufreq_cpu_get(cpu); - struct cpufreq_policy policy; + struct cpufreq_policy *policy = cpufreq_cpu_get(cpu); + struct cpufreq_policy new_policy; int ret; - if (!data) { + if (!policy) { ret = -ENODEV; goto no_policy; } @@ -1957,34 +1957,34 @@ int cpufreq_update_policy(unsigned int cpu) } pr_debug("updating policy for CPU %u\n", cpu); - memcpy(&policy, data, sizeof(struct cpufreq_policy)); - policy.min = data->user_policy.min; - policy.max = data->user_policy.max; - policy.policy = data->user_policy.policy; - policy.governor = data->user_policy.governor; + memcpy(&new_policy, policy, sizeof(struct cpufreq_policy)); + new_policy.min = policy->user_policy.min; + new_policy.max = policy->user_policy.max; + new_policy.policy = policy->user_policy.policy; + new_policy.governor = policy->user_policy.governor; /* * BIOS might change freq behind our back * -> ask driver for current freq and notify governors about a change */ if (cpufreq_driver->get) { - policy.cur = cpufreq_driver->get(cpu); - if (!data->cur) { + new_policy.cur = cpufreq_driver->get(cpu); + if (!policy->cur) { pr_debug("Driver did not initialize current freq"); - data->cur = policy.cur; + policy->cur = new_policy.cur; } else { - if (data->cur != policy.cur && cpufreq_driver->target) - cpufreq_out_of_sync(cpu, data->cur, - policy.cur); + if (policy->cur != new_policy.cur && cpufreq_driver->target) + cpufreq_out_of_sync(cpu, policy->cur, + new_policy.cur); } } - ret = __cpufreq_set_policy(data, &policy); + ret = __cpufreq_set_policy(policy, &new_policy); unlock_policy_rwsem_write(cpu); fail: - cpufreq_cpu_put(data); + cpufreq_cpu_put(policy); no_policy: return ret; } -- cgit v1.2.3 From d5b73cd870e2b049ef566aec2791dbf5fd26a7ec Mon Sep 17 00:00:00 2001 From: Viresh Kumar Date: Tue, 6 Aug 2013 22:53:06 +0530 Subject: cpufreq: Use sizeof(*ptr) convetion for computing sizes Chapter 14 of Documentation/CodingStyle says: The preferred form for passing a size of a struct is the following: p = kmalloc(sizeof(*p), ...); The alternative form where struct name is spelled out hurts readability and introduces an opportunity for a bug when the pointer variable type is changed but the corresponding sizeof that is passed to a memory allocator is not. This wasn't followed consistently in drivers/cpufreq, let's make it more consistent by always following this rule. Signed-off-by: Viresh Kumar Signed-off-by: Rafael J. Wysocki --- drivers/cpufreq/cpufreq.c | 9 ++++----- 1 file changed, 4 insertions(+), 5 deletions(-) (limited to 'drivers/cpufreq/cpufreq.c') diff --git a/drivers/cpufreq/cpufreq.c b/drivers/cpufreq/cpufreq.c index 1793fe82595d..9e83d9142072 100644 --- a/drivers/cpufreq/cpufreq.c +++ b/drivers/cpufreq/cpufreq.c @@ -873,7 +873,7 @@ static void cpufreq_init_policy(struct cpufreq_policy *policy) struct cpufreq_policy new_policy; int ret = 0; - memcpy(&new_policy, policy, sizeof(struct cpufreq_policy)); + memcpy(&new_policy, policy, sizeof(*policy)); /* assure that the starting sequence is run in __cpufreq_set_policy */ policy->governor = NULL; @@ -1818,7 +1818,7 @@ int cpufreq_get_policy(struct cpufreq_policy *policy, unsigned int cpu) if (!cpu_policy) return -EINVAL; - memcpy(policy, cpu_policy, sizeof(struct cpufreq_policy)); + memcpy(policy, cpu_policy, sizeof(*policy)); cpufreq_cpu_put(cpu_policy); return 0; @@ -1837,8 +1837,7 @@ static int __cpufreq_set_policy(struct cpufreq_policy *policy, pr_debug("setting new policy for CPU %u: %u - %u kHz\n", new_policy->cpu, new_policy->min, new_policy->max); - memcpy(&new_policy->cpuinfo, &policy->cpuinfo, - sizeof(struct cpufreq_cpuinfo)); + memcpy(&new_policy->cpuinfo, &policy->cpuinfo, sizeof(policy->cpuinfo)); if (new_policy->min > policy->max || new_policy->max < policy->min) { ret = -EINVAL; @@ -1957,7 +1956,7 @@ int cpufreq_update_policy(unsigned int cpu) } pr_debug("updating policy for CPU %u\n", cpu); - memcpy(&new_policy, policy, sizeof(struct cpufreq_policy)); + memcpy(&new_policy, policy, sizeof(*policy)); new_policy.min = policy->user_policy.min; new_policy.max = policy->user_policy.max; new_policy.policy = policy->user_policy.policy; -- cgit v1.2.3 From c88a1f8b96e7384627b918dfabbfc0c615a4a914 Mon Sep 17 00:00:00 2001 From: Lukasz Majewski Date: Tue, 6 Aug 2013 22:53:08 +0530 Subject: cpufreq: Store cpufreq policies in a list Policies available in the cpufreq framework are now linked together. They are accessible via cpufreq_policy_list defined in the cpufreq core. [rjw: Fix from Yinghai Lu folded in] Signed-off-by: Lukasz Majewski Signed-off-by: Myungjoo Ham Signed-off-by: Viresh Kumar Signed-off-by: Rafael J. Wysocki --- drivers/cpufreq/cpufreq.c | 12 ++++++++++++ 1 file changed, 12 insertions(+) (limited to 'drivers/cpufreq/cpufreq.c') diff --git a/drivers/cpufreq/cpufreq.c b/drivers/cpufreq/cpufreq.c index 9e83d9142072..75c5bd424d59 100644 --- a/drivers/cpufreq/cpufreq.c +++ b/drivers/cpufreq/cpufreq.c @@ -40,6 +40,7 @@ static DEFINE_PER_CPU(struct cpufreq_policy *, cpufreq_cpu_data); static DEFINE_PER_CPU(struct cpufreq_policy *, cpufreq_cpu_data_fallback); static DEFINE_RWLOCK(cpufreq_driver_lock); static DEFINE_MUTEX(cpufreq_governor_lock); +static LIST_HEAD(cpufreq_policy_list); #ifdef CONFIG_HOTPLUG_CPU /* This one keeps track of the previously set governor of a removed CPU */ @@ -952,6 +953,7 @@ static struct cpufreq_policy *cpufreq_policy_alloc(void) if (!zalloc_cpumask_var(&policy->related_cpus, GFP_KERNEL)) goto err_free_cpumask; + INIT_LIST_HEAD(&policy->policy_list); return policy; err_free_cpumask: @@ -964,6 +966,12 @@ err_free_policy: static void cpufreq_policy_free(struct cpufreq_policy *policy) { + unsigned long flags; + + write_lock_irqsave(&cpufreq_driver_lock, flags); + list_del(&policy->policy_list); + write_unlock_irqrestore(&cpufreq_driver_lock, flags); + free_cpumask_var(policy->related_cpus); free_cpumask_var(policy->cpus); kfree(policy); @@ -1077,6 +1085,10 @@ static int __cpufreq_add_dev(struct device *dev, struct subsys_interface *sif, ret = cpufreq_add_dev_interface(policy, dev); if (ret) goto err_out_unregister; + + write_lock_irqsave(&cpufreq_driver_lock, flags); + list_add(&policy->policy_list, &cpufreq_policy_list); + write_unlock_irqrestore(&cpufreq_driver_lock, flags); } cpufreq_init_policy(policy); -- cgit v1.2.3 From eb608521f1e25a8c14295b6d9a3853c3cd8c6cf8 Mon Sep 17 00:00:00 2001 From: Viresh Kumar Date: Tue, 6 Aug 2013 22:53:09 +0530 Subject: cpufreq: Use cpufreq_policy_list for iterating over policies To iterate over all policies we currently iterate over all CPUs and then get the policy for each of them. Let's use the newly created cpufreq_policy_list for this purpose. [rjw: Changelog] Signed-off-by: Viresh Kumar Signed-off-by: Rafael J. Wysocki --- drivers/cpufreq/cpufreq.c | 10 +++++----- 1 file changed, 5 insertions(+), 5 deletions(-) (limited to 'drivers/cpufreq/cpufreq.c') diff --git a/drivers/cpufreq/cpufreq.c b/drivers/cpufreq/cpufreq.c index 75c5bd424d59..37af929746af 100644 --- a/drivers/cpufreq/cpufreq.c +++ b/drivers/cpufreq/cpufreq.c @@ -985,8 +985,8 @@ static int __cpufreq_add_dev(struct device *dev, struct subsys_interface *sif, struct cpufreq_policy *policy; unsigned long flags; #ifdef CONFIG_HOTPLUG_CPU + struct cpufreq_policy *tpolicy; struct cpufreq_governor *gov; - int sibling; #endif if (cpu_is_offline(cpu)) @@ -1006,11 +1006,11 @@ static int __cpufreq_add_dev(struct device *dev, struct subsys_interface *sif, #ifdef CONFIG_HOTPLUG_CPU /* Check if this cpu was hot-unplugged earlier and has siblings */ read_lock_irqsave(&cpufreq_driver_lock, flags); - for_each_online_cpu(sibling) { - struct cpufreq_policy *cp = per_cpu(cpufreq_cpu_data, sibling); - if (cp && cpumask_test_cpu(cpu, cp->related_cpus)) { + list_for_each_entry(tpolicy, &cpufreq_policy_list, policy_list) { + if (cpumask_test_cpu(cpu, tpolicy->related_cpus)) { read_unlock_irqrestore(&cpufreq_driver_lock, flags); - return cpufreq_add_policy_cpu(cp, cpu, dev, frozen); + return cpufreq_add_policy_cpu(tpolicy, cpu, dev, + frozen); } } read_unlock_irqrestore(&cpufreq_driver_lock, flags); -- cgit v1.2.3 From fe492f3f0332e23cc6ca4913e5a2ed78e1888902 Mon Sep 17 00:00:00 2001 From: Viresh Kumar Date: Tue, 6 Aug 2013 22:53:10 +0530 Subject: cpufreq: Fix broken usage of governor->owner's refcount The cpufreq governor owner refcount usage is broken. We should only increment that refcount when a CPUFREQ_GOV_POLICY_INIT event has come and it should only be decremented if CPUFREQ_GOV_POLICY_EXIT has come. Currently, there can be situations where the governor is in use, but we have allowed it to be unloaded which may result in undefined behavior. Let's fix it. Signed-off-by: Viresh Kumar Signed-off-by: Rafael J. Wysocki --- drivers/cpufreq/cpufreq.c | 14 +++++++------- 1 file changed, 7 insertions(+), 7 deletions(-) (limited to 'drivers/cpufreq/cpufreq.c') diff --git a/drivers/cpufreq/cpufreq.c b/drivers/cpufreq/cpufreq.c index 37af929746af..f149e14f77c7 100644 --- a/drivers/cpufreq/cpufreq.c +++ b/drivers/cpufreq/cpufreq.c @@ -1709,8 +1709,9 @@ static int __cpufreq_governor(struct cpufreq_policy *policy, } } - if (!try_module_get(policy->governor->owner)) - return -EINVAL; + if (event == CPUFREQ_GOV_POLICY_INIT) + if (!try_module_get(policy->governor->owner)) + return -EINVAL; pr_debug("__cpufreq_governor for CPU %u, event %u\n", policy->cpu, event); @@ -1719,6 +1720,8 @@ static int __cpufreq_governor(struct cpufreq_policy *policy, if ((!policy->governor_enabled && (event == CPUFREQ_GOV_STOP)) || (policy->governor_enabled && (event == CPUFREQ_GOV_START))) { mutex_unlock(&cpufreq_governor_lock); + if (event == CPUFREQ_GOV_POLICY_INIT) + module_put(policy->governor->owner); return -EBUSY; } @@ -1746,11 +1749,8 @@ static int __cpufreq_governor(struct cpufreq_policy *policy, mutex_unlock(&cpufreq_governor_lock); } - /* we keep one module reference alive for - each CPU governed by this CPU */ - if ((event != CPUFREQ_GOV_START) || ret) - module_put(policy->governor->owner); - if ((event == CPUFREQ_GOV_STOP) && !ret) + if (((event == CPUFREQ_GOV_POLICY_INIT) && ret) || + ((event == CPUFREQ_GOV_POLICY_EXIT) && !ret)) module_put(policy->governor->owner); return ret; -- cgit v1.2.3 From 6eed9404ab3c4baea54ce4c7e862e69df1d39f38 Mon Sep 17 00:00:00 2001 From: Viresh Kumar Date: Tue, 6 Aug 2013 22:53:11 +0530 Subject: cpufreq: Use rwsem for protecting critical sections Critical sections of the cpufreq core are protected with the help of the driver module owner's refcount, which isn't the correct approach, because it causes rmmod to return an error when some routine has updated that refcount. Let's use rwsem for this purpose instead. Only cpufreq_unregister_driver() will use write sem and everybody else will use read sem. [rjw: Subject & changelog] Signed-off-by: Viresh Kumar Signed-off-by: Rafael J. Wysocki --- drivers/cpufreq/cpufreq.c | 135 ++++++++++++++++++++-------------------------- 1 file changed, 57 insertions(+), 78 deletions(-) (limited to 'drivers/cpufreq/cpufreq.c') diff --git a/drivers/cpufreq/cpufreq.c b/drivers/cpufreq/cpufreq.c index f149e14f77c7..c9bbfeef92e3 100644 --- a/drivers/cpufreq/cpufreq.c +++ b/drivers/cpufreq/cpufreq.c @@ -91,6 +91,12 @@ static void unlock_policy_rwsem_##mode(int cpu) \ unlock_policy_rwsem(read, cpu); unlock_policy_rwsem(write, cpu); +/* + * rwsem to guarantee that cpufreq driver module doesn't unload during critical + * sections + */ +static DECLARE_RWSEM(cpufreq_rwsem); + /* internal prototypes */ static int __cpufreq_governor(struct cpufreq_policy *policy, unsigned int event); @@ -178,78 +184,46 @@ u64 get_cpu_idle_time(unsigned int cpu, u64 *wall, int io_busy) } EXPORT_SYMBOL_GPL(get_cpu_idle_time); -static struct cpufreq_policy *__cpufreq_cpu_get(unsigned int cpu, bool sysfs) +struct cpufreq_policy *cpufreq_cpu_get(unsigned int cpu) { - struct cpufreq_policy *policy; + struct cpufreq_policy *policy = NULL; unsigned long flags; - if (cpu >= nr_cpu_ids) - goto err_out; + if (cpufreq_disabled() || (cpu >= nr_cpu_ids)) + return NULL; + + if (!down_read_trylock(&cpufreq_rwsem)) + return NULL; /* get the cpufreq driver */ read_lock_irqsave(&cpufreq_driver_lock, flags); - if (!cpufreq_driver) - goto err_out_unlock; - - if (!try_module_get(cpufreq_driver->owner)) - goto err_out_unlock; + if (cpufreq_driver) { + /* get the CPU */ + policy = per_cpu(cpufreq_cpu_data, cpu); + if (policy) + kobject_get(&policy->kobj); + } - /* get the CPU */ - policy = per_cpu(cpufreq_cpu_data, cpu); + read_unlock_irqrestore(&cpufreq_driver_lock, flags); if (!policy) - goto err_out_put_module; - - if (!sysfs && !kobject_get(&policy->kobj)) - goto err_out_put_module; + up_read(&cpufreq_rwsem); - read_unlock_irqrestore(&cpufreq_driver_lock, flags); return policy; - -err_out_put_module: - module_put(cpufreq_driver->owner); -err_out_unlock: - read_unlock_irqrestore(&cpufreq_driver_lock, flags); -err_out: - return NULL; -} - -struct cpufreq_policy *cpufreq_cpu_get(unsigned int cpu) -{ - if (cpufreq_disabled()) - return NULL; - - return __cpufreq_cpu_get(cpu, false); } EXPORT_SYMBOL_GPL(cpufreq_cpu_get); -static struct cpufreq_policy *cpufreq_cpu_get_sysfs(unsigned int cpu) -{ - return __cpufreq_cpu_get(cpu, true); -} - -static void __cpufreq_cpu_put(struct cpufreq_policy *policy, bool sysfs) -{ - if (!sysfs) - kobject_put(&policy->kobj); - module_put(cpufreq_driver->owner); -} - void cpufreq_cpu_put(struct cpufreq_policy *policy) { if (cpufreq_disabled()) return; - __cpufreq_cpu_put(policy, false); + kobject_put(&policy->kobj); + up_read(&cpufreq_rwsem); } EXPORT_SYMBOL_GPL(cpufreq_cpu_put); -static void cpufreq_cpu_put_sysfs(struct cpufreq_policy *policy) -{ - __cpufreq_cpu_put(policy, true); -} - /********************************************************************* * EXTERNALLY AFFECTING FREQUENCY CHANGES * *********************************************************************/ @@ -694,12 +668,12 @@ static ssize_t show(struct kobject *kobj, struct attribute *attr, char *buf) struct cpufreq_policy *policy = to_policy(kobj); struct freq_attr *fattr = to_attr(attr); ssize_t ret = -EINVAL; - policy = cpufreq_cpu_get_sysfs(policy->cpu); - if (!policy) - goto no_policy; + + if (!down_read_trylock(&cpufreq_rwsem)) + goto exit; if (lock_policy_rwsem_read(policy->cpu) < 0) - goto fail; + goto up_read; if (fattr->show) ret = fattr->show(policy, buf); @@ -707,9 +681,10 @@ static ssize_t show(struct kobject *kobj, struct attribute *attr, char *buf) ret = -EIO; unlock_policy_rwsem_read(policy->cpu); -fail: - cpufreq_cpu_put_sysfs(policy); -no_policy: + +up_read: + up_read(&cpufreq_rwsem); +exit: return ret; } @@ -719,12 +694,12 @@ static ssize_t store(struct kobject *kobj, struct attribute *attr, struct cpufreq_policy *policy = to_policy(kobj); struct freq_attr *fattr = to_attr(attr); ssize_t ret = -EINVAL; - policy = cpufreq_cpu_get_sysfs(policy->cpu); - if (!policy) - goto no_policy; + + if (!down_read_trylock(&cpufreq_rwsem)) + goto exit; if (lock_policy_rwsem_write(policy->cpu) < 0) - goto fail; + goto up_read; if (fattr->store) ret = fattr->store(policy, buf, count); @@ -732,9 +707,10 @@ static ssize_t store(struct kobject *kobj, struct attribute *attr, ret = -EIO; unlock_policy_rwsem_write(policy->cpu); -fail: - cpufreq_cpu_put_sysfs(policy); -no_policy: + +up_read: + up_read(&cpufreq_rwsem); +exit: return ret; } @@ -1003,25 +979,24 @@ static int __cpufreq_add_dev(struct device *dev, struct subsys_interface *sif, return 0; } + if (!down_read_trylock(&cpufreq_rwsem)) + return 0; + #ifdef CONFIG_HOTPLUG_CPU /* Check if this cpu was hot-unplugged earlier and has siblings */ read_lock_irqsave(&cpufreq_driver_lock, flags); list_for_each_entry(tpolicy, &cpufreq_policy_list, policy_list) { if (cpumask_test_cpu(cpu, tpolicy->related_cpus)) { read_unlock_irqrestore(&cpufreq_driver_lock, flags); - return cpufreq_add_policy_cpu(tpolicy, cpu, dev, - frozen); + ret = cpufreq_add_policy_cpu(tpolicy, cpu, dev, frozen); + up_read(&cpufreq_rwsem); + return ret; } } read_unlock_irqrestore(&cpufreq_driver_lock, flags); #endif #endif - if (!try_module_get(cpufreq_driver->owner)) { - ret = -EINVAL; - goto module_out; - } - if (frozen) /* Restore the saved policy when doing light-weight init */ policy = cpufreq_policy_restore(cpu); @@ -1094,7 +1069,8 @@ static int __cpufreq_add_dev(struct device *dev, struct subsys_interface *sif, cpufreq_init_policy(policy); kobject_uevent(&policy->kobj, KOBJ_ADD); - module_put(cpufreq_driver->owner); + up_read(&cpufreq_rwsem); + pr_debug("initialization complete\n"); return 0; @@ -1112,8 +1088,8 @@ err_set_policy_cpu: per_cpu(cpufreq_policy_cpu, cpu) = -1; cpufreq_policy_free(policy); nomem_out: - module_put(cpufreq_driver->owner); -module_out: + up_read(&cpufreq_rwsem); + return ret; } @@ -1425,10 +1401,9 @@ static unsigned int __cpufreq_get(unsigned int cpu) unsigned int cpufreq_get(unsigned int cpu) { unsigned int ret_freq = 0; - struct cpufreq_policy *policy = cpufreq_cpu_get(cpu); - if (!policy) - goto out; + if (!down_read_trylock(&cpufreq_rwsem)) + return 0; if (unlikely(lock_policy_rwsem_read(cpu))) goto out_policy; @@ -1438,8 +1413,8 @@ unsigned int cpufreq_get(unsigned int cpu) unlock_policy_rwsem_read(cpu); out_policy: - cpufreq_cpu_put(policy); -out: + up_read(&cpufreq_rwsem); + return ret_freq; } EXPORT_SYMBOL(cpufreq_get); @@ -2132,9 +2107,13 @@ int cpufreq_unregister_driver(struct cpufreq_driver *driver) subsys_interface_unregister(&cpufreq_interface); unregister_hotcpu_notifier(&cpufreq_cpu_notifier); + down_write(&cpufreq_rwsem); write_lock_irqsave(&cpufreq_driver_lock, flags); + cpufreq_driver = NULL; + write_unlock_irqrestore(&cpufreq_driver_lock, flags); + up_write(&cpufreq_rwsem); return 0; } -- cgit v1.2.3 From 3de9bdeb28638e164d1f0eb38dd68e3f5d2ac95c Mon Sep 17 00:00:00 2001 From: Viresh Kumar Date: Tue, 6 Aug 2013 22:53:13 +0530 Subject: cpufreq: improve error checking on return values of __cpufreq_governor() The __cpufreq_governor() function can fail in rare cases especially if there are bugs in cpufreq drivers. Thus we must stop processing as soon as this routine fails, otherwise it may result in undefined behavior. This patch adds error checking code whenever this routine is called from any place. Signed-off-by: Viresh Kumar Signed-off-by: Rafael J. Wysocki --- drivers/cpufreq/cpufreq.c | 48 +++++++++++++++++++++++++++++++++++------------ 1 file changed, 36 insertions(+), 12 deletions(-) (limited to 'drivers/cpufreq/cpufreq.c') diff --git a/drivers/cpufreq/cpufreq.c b/drivers/cpufreq/cpufreq.c index c9bbfeef92e3..37a687467329 100644 --- a/drivers/cpufreq/cpufreq.c +++ b/drivers/cpufreq/cpufreq.c @@ -874,8 +874,13 @@ static int cpufreq_add_policy_cpu(struct cpufreq_policy *policy, int ret = 0, has_target = !!cpufreq_driver->target; unsigned long flags; - if (has_target) - __cpufreq_governor(policy, CPUFREQ_GOV_STOP); + if (has_target) { + ret = __cpufreq_governor(policy, CPUFREQ_GOV_STOP); + if (ret) { + pr_err("%s: Failed to stop governor\n", __func__); + return ret; + } + } lock_policy_rwsem_write(policy->cpu); @@ -889,8 +894,11 @@ static int cpufreq_add_policy_cpu(struct cpufreq_policy *policy, unlock_policy_rwsem_write(policy->cpu); if (has_target) { - __cpufreq_governor(policy, CPUFREQ_GOV_START); - __cpufreq_governor(policy, CPUFREQ_GOV_LIMITS); + if ((ret = __cpufreq_governor(policy, CPUFREQ_GOV_START)) || + (ret = __cpufreq_governor(policy, CPUFREQ_GOV_LIMITS))) { + pr_err("%s: Failed to start governor\n", __func__); + return ret; + } } /* Don't touch sysfs links during light-weight init */ @@ -1172,7 +1180,7 @@ static int __cpufreq_remove_dev(struct device *dev, struct subsys_interface *sif, bool frozen) { unsigned int cpu = dev->id, cpus; - int new_cpu; + int new_cpu, ret; unsigned long flags; struct cpufreq_policy *policy; struct kobject *kobj; @@ -1196,8 +1204,13 @@ static int __cpufreq_remove_dev(struct device *dev, return -EINVAL; } - if (cpufreq_driver->target) - __cpufreq_governor(policy, CPUFREQ_GOV_STOP); + if (cpufreq_driver->target) { + ret = __cpufreq_governor(policy, CPUFREQ_GOV_STOP); + if (ret) { + pr_err("%s: Failed to stop governor\n", __func__); + return ret; + } + } #ifdef CONFIG_HOTPLUG_CPU if (!cpufreq_driver->setpolicy) @@ -1231,8 +1244,15 @@ static int __cpufreq_remove_dev(struct device *dev, /* If cpu is last user of policy, free policy */ if (cpus == 1) { - if (cpufreq_driver->target) - __cpufreq_governor(policy, CPUFREQ_GOV_POLICY_EXIT); + if (cpufreq_driver->target) { + ret = __cpufreq_governor(policy, + CPUFREQ_GOV_POLICY_EXIT); + if (ret) { + pr_err("%s: Failed to exit governor\n", + __func__); + return ret; + } + } if (!frozen) { lock_policy_rwsem_read(cpu); @@ -1263,8 +1283,12 @@ static int __cpufreq_remove_dev(struct device *dev, cpufreq_policy_free(policy); } else { if (cpufreq_driver->target) { - __cpufreq_governor(policy, CPUFREQ_GOV_START); - __cpufreq_governor(policy, CPUFREQ_GOV_LIMITS); + if ((ret = __cpufreq_governor(policy, CPUFREQ_GOV_START)) || + (ret = __cpufreq_governor(policy, CPUFREQ_GOV_LIMITS))) { + pr_err("%s: Failed to start governor\n", + __func__); + return ret; + } } } @@ -1912,7 +1936,7 @@ static int __cpufreq_set_policy(struct cpufreq_policy *policy, /* might be a policy change, too, so fall through */ } pr_debug("governor: change or update limits\n"); - __cpufreq_governor(policy, CPUFREQ_GOV_LIMITS); + ret = __cpufreq_governor(policy, CPUFREQ_GOV_LIMITS); } error_out: -- cgit v1.2.3 From 878f6e074e9a7784a6e351512eace4ccb3542eef Mon Sep 17 00:00:00 2001 From: "Rafael J. Wysocki" Date: Sun, 18 Aug 2013 15:35:59 +0200 Subject: Revert "cpufreq: Use cpufreq_policy_list for iterating over policies" Revert commit eb60852 (cpufreq: Use cpufreq_policy_list for iterating over policies), because it breaks system suspend/resume on multiple machines. It either causes resume to block indefinitely or causes the BUG_ON() in lock_policy_rwsem_##mode() to trigger on sysfs accesses to cpufreq attributes. Conflicts: drivers/cpufreq/cpufreq.c --- drivers/cpufreq/cpufreq.c | 9 +++++---- 1 file changed, 5 insertions(+), 4 deletions(-) (limited to 'drivers/cpufreq/cpufreq.c') diff --git a/drivers/cpufreq/cpufreq.c b/drivers/cpufreq/cpufreq.c index 37a687467329..c0ef84d601b7 100644 --- a/drivers/cpufreq/cpufreq.c +++ b/drivers/cpufreq/cpufreq.c @@ -969,8 +969,8 @@ static int __cpufreq_add_dev(struct device *dev, struct subsys_interface *sif, struct cpufreq_policy *policy; unsigned long flags; #ifdef CONFIG_HOTPLUG_CPU - struct cpufreq_policy *tpolicy; struct cpufreq_governor *gov; + int sibling; #endif if (cpu_is_offline(cpu)) @@ -993,10 +993,11 @@ static int __cpufreq_add_dev(struct device *dev, struct subsys_interface *sif, #ifdef CONFIG_HOTPLUG_CPU /* Check if this cpu was hot-unplugged earlier and has siblings */ read_lock_irqsave(&cpufreq_driver_lock, flags); - list_for_each_entry(tpolicy, &cpufreq_policy_list, policy_list) { - if (cpumask_test_cpu(cpu, tpolicy->related_cpus)) { + for_each_online_cpu(sibling) { + struct cpufreq_policy *cp = per_cpu(cpufreq_cpu_data, sibling); + if (cp && cpumask_test_cpu(cpu, cp->related_cpus)) { read_unlock_irqrestore(&cpufreq_driver_lock, flags); - ret = cpufreq_add_policy_cpu(tpolicy, cpu, dev, frozen); + ret = cpufreq_add_policy_cpu(cp, cpu, dev, frozen); up_read(&cpufreq_rwsem); return ret; } -- cgit v1.2.3 From edab2fbc21b9eb37007ad8bffe1159d536bbb451 Mon Sep 17 00:00:00 2001 From: Viresh Kumar Date: Tue, 20 Aug 2013 12:08:22 +0530 Subject: cpufreq: Fix white space in __cpufreq_remove_dev() Align closing brace '}' of an if block. [rjw: Subject and changelog] Signed-off-by: Viresh Kumar Signed-off-by: Rafael J. Wysocki --- drivers/cpufreq/cpufreq.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'drivers/cpufreq/cpufreq.c') diff --git a/drivers/cpufreq/cpufreq.c b/drivers/cpufreq/cpufreq.c index c0ef84d601b7..fedc8420214e 100644 --- a/drivers/cpufreq/cpufreq.c +++ b/drivers/cpufreq/cpufreq.c @@ -1253,7 +1253,7 @@ static int __cpufreq_remove_dev(struct device *dev, __func__); return ret; } - } + } if (!frozen) { lock_policy_rwsem_read(cpu); -- cgit v1.2.3 From 9515f4d69b92feafe37581047a1bb41e41602faa Mon Sep 17 00:00:00 2001 From: Viresh Kumar Date: Tue, 20 Aug 2013 12:08:23 +0530 Subject: cpufreq: remove policy from cpufreq_policy_list during suspend cpufreq_policy_list is a list of active policies. We do remove policies from this list when all CPUs belonging to that policy are removed. But during system suspend we don't really free a policy struct as it will be used again during resume, so we didn't remove it from cpufreq_policy_list as well.. However, this is incorrect. We are saying this policy isn't valid anymore and must not be referenced (though we haven't freed it), but it can still be used by code that iterates over cpufreq_policy_list. Remove policy from this list during system suspend as well. Of course, we must add it back whenever the first CPU belonging to that policy shows up. [rjw: Changelog] Signed-off-by: Viresh Kumar Signed-off-by: Rafael J. Wysocki --- drivers/cpufreq/cpufreq.c | 19 +++++++++---------- 1 file changed, 9 insertions(+), 10 deletions(-) (limited to 'drivers/cpufreq/cpufreq.c') diff --git a/drivers/cpufreq/cpufreq.c b/drivers/cpufreq/cpufreq.c index fedc8420214e..030212104fe6 100644 --- a/drivers/cpufreq/cpufreq.c +++ b/drivers/cpufreq/cpufreq.c @@ -950,12 +950,6 @@ err_free_policy: static void cpufreq_policy_free(struct cpufreq_policy *policy) { - unsigned long flags; - - write_lock_irqsave(&cpufreq_driver_lock, flags); - list_del(&policy->policy_list); - write_unlock_irqrestore(&cpufreq_driver_lock, flags); - free_cpumask_var(policy->related_cpus); free_cpumask_var(policy->cpus); kfree(policy); @@ -1069,12 +1063,12 @@ static int __cpufreq_add_dev(struct device *dev, struct subsys_interface *sif, ret = cpufreq_add_dev_interface(policy, dev); if (ret) goto err_out_unregister; - - write_lock_irqsave(&cpufreq_driver_lock, flags); - list_add(&policy->policy_list, &cpufreq_policy_list); - write_unlock_irqrestore(&cpufreq_driver_lock, flags); } + write_lock_irqsave(&cpufreq_driver_lock, flags); + list_add(&policy->policy_list, &cpufreq_policy_list); + write_unlock_irqrestore(&cpufreq_driver_lock, flags); + cpufreq_init_policy(policy); kobject_uevent(&policy->kobj, KOBJ_ADD); @@ -1280,6 +1274,11 @@ static int __cpufreq_remove_dev(struct device *dev, if (cpufreq_driver->exit) cpufreq_driver->exit(policy); + /* Remove policy from list of active policies */ + write_lock_irqsave(&cpufreq_driver_lock, flags); + list_del(&policy->policy_list); + write_unlock_irqrestore(&cpufreq_driver_lock, flags); + if (!frozen) cpufreq_policy_free(policy); } else { -- cgit v1.2.3 From 9e9fd801676a946b759a8669baa24ba327c8c903 Mon Sep 17 00:00:00 2001 From: Viresh Kumar Date: Tue, 20 Aug 2013 12:08:24 +0530 Subject: cpufreq: remove unnecessary check in __cpufreq_governor() We don't need to check if event is CPUFREQ_GOV_POLICY_INIT and put governor module as we are sure event can only be START/STOP here. Remove the useless check. Signed-off-by: Viresh Kumar Signed-off-by: Rafael J. Wysocki --- drivers/cpufreq/cpufreq.c | 2 -- 1 file changed, 2 deletions(-) (limited to 'drivers/cpufreq/cpufreq.c') diff --git a/drivers/cpufreq/cpufreq.c b/drivers/cpufreq/cpufreq.c index 030212104fe6..b03a8514b574 100644 --- a/drivers/cpufreq/cpufreq.c +++ b/drivers/cpufreq/cpufreq.c @@ -1719,8 +1719,6 @@ static int __cpufreq_governor(struct cpufreq_policy *policy, if ((!policy->governor_enabled && (event == CPUFREQ_GOV_STOP)) || (policy->governor_enabled && (event == CPUFREQ_GOV_START))) { mutex_unlock(&cpufreq_governor_lock); - if (event == CPUFREQ_GOV_POLICY_INIT) - module_put(policy->governor->owner); return -EBUSY; } -- cgit v1.2.3 From 474deff744c4012f07cfa994947d7c6260c9ab89 Mon Sep 17 00:00:00 2001 From: Viresh Kumar Date: Tue, 20 Aug 2013 12:08:25 +0530 Subject: cpufreq: remove cpufreq_policy_cpu per-cpu variable cpufreq_policy_cpu per-cpu variables are used for storing the ID of the CPU that manages the given CPU's policy. However, we also store a policy pointer for each cpu in cpufreq_cpu_data, so the cpufreq_policy_cpu information is simply redundant. It is better to use cpufreq_cpu_data to retrieve a policy and get policy->cpu from there, so make that happen everywhere and drop the cpufreq_policy_cpu per-cpu variables which aren't necessary any more. [rjw: Changelog] Signed-off-by: Viresh Kumar Signed-off-by: Rafael J. Wysocki --- drivers/cpufreq/cpufreq.c | 45 ++++++++++----------------------------------- 1 file changed, 10 insertions(+), 35 deletions(-) (limited to 'drivers/cpufreq/cpufreq.c') diff --git a/drivers/cpufreq/cpufreq.c b/drivers/cpufreq/cpufreq.c index b03a8514b574..0586bd20a474 100644 --- a/drivers/cpufreq/cpufreq.c +++ b/drivers/cpufreq/cpufreq.c @@ -64,15 +64,14 @@ static DEFINE_PER_CPU(char[CPUFREQ_NAME_LEN], cpufreq_cpu_governor); * - Lock should not be held across * __cpufreq_governor(data, CPUFREQ_GOV_STOP); */ -static DEFINE_PER_CPU(int, cpufreq_policy_cpu); static DEFINE_PER_CPU(struct rw_semaphore, cpu_policy_rwsem); #define lock_policy_rwsem(mode, cpu) \ static int lock_policy_rwsem_##mode(int cpu) \ { \ - int policy_cpu = per_cpu(cpufreq_policy_cpu, cpu); \ - BUG_ON(policy_cpu == -1); \ - down_##mode(&per_cpu(cpu_policy_rwsem, policy_cpu)); \ + struct cpufreq_policy *policy = per_cpu(cpufreq_cpu_data, cpu); \ + BUG_ON(!policy); \ + down_##mode(&per_cpu(cpu_policy_rwsem, policy->cpu)); \ \ return 0; \ } @@ -83,9 +82,9 @@ lock_policy_rwsem(write, cpu); #define unlock_policy_rwsem(mode, cpu) \ static void unlock_policy_rwsem_##mode(int cpu) \ { \ - int policy_cpu = per_cpu(cpufreq_policy_cpu, cpu); \ - BUG_ON(policy_cpu == -1); \ - up_##mode(&per_cpu(cpu_policy_rwsem, policy_cpu)); \ + struct cpufreq_policy *policy = per_cpu(cpufreq_cpu_data, cpu); \ + BUG_ON(!policy); \ + up_##mode(&per_cpu(cpu_policy_rwsem, policy->cpu)); \ } unlock_policy_rwsem(read, cpu); @@ -887,7 +886,6 @@ static int cpufreq_add_policy_cpu(struct cpufreq_policy *policy, write_lock_irqsave(&cpufreq_driver_lock, flags); cpumask_set_cpu(cpu, policy->cpus); - per_cpu(cpufreq_policy_cpu, cpu) = policy->cpu; per_cpu(cpufreq_cpu_data, cpu) = policy; write_unlock_irqrestore(&cpufreq_driver_lock, flags); @@ -1013,9 +1011,6 @@ static int __cpufreq_add_dev(struct device *dev, struct subsys_interface *sif, policy->governor = CPUFREQ_DEFAULT_GOVERNOR; cpumask_copy(policy->cpus, cpumask_of(cpu)); - /* Initially set CPU itself as the policy_cpu */ - per_cpu(cpufreq_policy_cpu, cpu) = cpu; - init_completion(&policy->kobj_unregister); INIT_WORK(&policy->update, handle_update); @@ -1053,10 +1048,8 @@ static int __cpufreq_add_dev(struct device *dev, struct subsys_interface *sif, #endif write_lock_irqsave(&cpufreq_driver_lock, flags); - for_each_cpu(j, policy->cpus) { + for_each_cpu(j, policy->cpus) per_cpu(cpufreq_cpu_data, j) = policy; - per_cpu(cpufreq_policy_cpu, j) = policy->cpu; - } write_unlock_irqrestore(&cpufreq_driver_lock, flags); if (!frozen) { @@ -1080,15 +1073,11 @@ static int __cpufreq_add_dev(struct device *dev, struct subsys_interface *sif, err_out_unregister: write_lock_irqsave(&cpufreq_driver_lock, flags); - for_each_cpu(j, policy->cpus) { + for_each_cpu(j, policy->cpus) per_cpu(cpufreq_cpu_data, j) = NULL; - if (j != cpu) - per_cpu(cpufreq_policy_cpu, j) = -1; - } write_unlock_irqrestore(&cpufreq_driver_lock, flags); err_set_policy_cpu: - per_cpu(cpufreq_policy_cpu, cpu) = -1; cpufreq_policy_free(policy); nomem_out: up_read(&cpufreq_rwsem); @@ -1112,14 +1101,9 @@ static int cpufreq_add_dev(struct device *dev, struct subsys_interface *sif) static void update_policy_cpu(struct cpufreq_policy *policy, unsigned int cpu) { - int j; - policy->last_cpu = policy->cpu; policy->cpu = cpu; - for_each_cpu(j, policy->cpus) - per_cpu(cpufreq_policy_cpu, j) = cpu; - #ifdef CONFIG_CPU_FREQ_TABLE cpufreq_frequency_table_update_policy_cpu(policy); #endif @@ -1131,7 +1115,6 @@ static int cpufreq_nominate_new_policy_cpu(struct cpufreq_policy *policy, unsigned int old_cpu, bool frozen) { struct device *cpu_dev; - unsigned long flags; int ret; /* first sibling now owns the new sysfs dir */ @@ -1148,11 +1131,6 @@ static int cpufreq_nominate_new_policy_cpu(struct cpufreq_policy *policy, WARN_ON(lock_policy_rwsem_write(old_cpu)); cpumask_set_cpu(old_cpu, policy->cpus); - - write_lock_irqsave(&cpufreq_driver_lock, flags); - per_cpu(cpufreq_cpu_data, old_cpu) = policy; - write_unlock_irqrestore(&cpufreq_driver_lock, flags); - unlock_policy_rwsem_write(old_cpu); ret = sysfs_create_link(&cpu_dev->kobj, &policy->kobj, @@ -1186,7 +1164,6 @@ static int __cpufreq_remove_dev(struct device *dev, write_lock_irqsave(&cpufreq_driver_lock, flags); policy = per_cpu(cpufreq_cpu_data, cpu); - per_cpu(cpufreq_cpu_data, cpu) = NULL; /* Save the policy somewhere when doing a light-weight tear-down */ if (frozen) @@ -1292,7 +1269,7 @@ static int __cpufreq_remove_dev(struct device *dev, } } - per_cpu(cpufreq_policy_cpu, cpu) = -1; + per_cpu(cpufreq_cpu_data, cpu) = NULL; return 0; } @@ -2148,10 +2125,8 @@ static int __init cpufreq_core_init(void) if (cpufreq_disabled()) return -ENODEV; - for_each_possible_cpu(cpu) { - per_cpu(cpufreq_policy_cpu, cpu) = -1; + for_each_possible_cpu(cpu) init_rwsem(&per_cpu(cpu_policy_rwsem, cpu)); - } cpufreq_global_kobject = kobject_create(); BUG_ON(!cpufreq_global_kobject); -- cgit v1.2.3 From 1b27429446f0c37353179544e844dc2086fa2353 Mon Sep 17 00:00:00 2001 From: Viresh Kumar Date: Tue, 20 Aug 2013 12:08:26 +0530 Subject: cpufreq: Use cpufreq_policy_list for iterating over policies To iterate over all policies we currently iterate over all online CPUs and then get the policy for each of them which is suboptimal. Use the newly created cpufreq_policy_list for this purpose instead. Signed-off-by: Viresh Kumar Signed-off-by: Rafael J. Wysocki --- drivers/cpufreq/cpufreq.c | 9 ++++----- 1 file changed, 4 insertions(+), 5 deletions(-) (limited to 'drivers/cpufreq/cpufreq.c') diff --git a/drivers/cpufreq/cpufreq.c b/drivers/cpufreq/cpufreq.c index 0586bd20a474..81ceea6ed630 100644 --- a/drivers/cpufreq/cpufreq.c +++ b/drivers/cpufreq/cpufreq.c @@ -961,8 +961,8 @@ static int __cpufreq_add_dev(struct device *dev, struct subsys_interface *sif, struct cpufreq_policy *policy; unsigned long flags; #ifdef CONFIG_HOTPLUG_CPU + struct cpufreq_policy *tpolicy; struct cpufreq_governor *gov; - int sibling; #endif if (cpu_is_offline(cpu)) @@ -985,11 +985,10 @@ static int __cpufreq_add_dev(struct device *dev, struct subsys_interface *sif, #ifdef CONFIG_HOTPLUG_CPU /* Check if this cpu was hot-unplugged earlier and has siblings */ read_lock_irqsave(&cpufreq_driver_lock, flags); - for_each_online_cpu(sibling) { - struct cpufreq_policy *cp = per_cpu(cpufreq_cpu_data, sibling); - if (cp && cpumask_test_cpu(cpu, cp->related_cpus)) { + list_for_each_entry(tpolicy, &cpufreq_policy_list, policy_list) { + if (cpumask_test_cpu(cpu, tpolicy->related_cpus)) { read_unlock_irqrestore(&cpufreq_driver_lock, flags); - ret = cpufreq_add_policy_cpu(cp, cpu, dev, frozen); + ret = cpufreq_add_policy_cpu(tpolicy, cpu, dev, frozen); up_read(&cpufreq_rwsem); return ret; } -- cgit v1.2.3 From 5025d628c8659fbf939f929107bf76db81dcdfff Mon Sep 17 00:00:00 2001 From: Li Zhong Date: Wed, 21 Aug 2013 01:31:08 +0200 Subject: cpufreq: fix bad unlock balance on !CONFIG_SMP This patch tries to fix lockdep complaint attached below. It seems that we should always read acquire the cpufreq_rwsem, whether CONFIG_SMP is enabled or not. And CONFIG_HOTPLUG_CPU depends on CONFIG_SMP, so it seems we don't need CONFIG_SMP for the code enabled by CONFIG_HOTPLUG_CPU. [ 0.504191] ===================================== [ 0.504627] [ BUG: bad unlock balance detected! ] [ 0.504627] 3.11.0-rc6-next-20130819 #1 Not tainted [ 0.504627] ------------------------------------- [ 0.504627] swapper/1 is trying to release lock (cpufreq_rwsem) at: [ 0.504627] [] cpufreq_add_dev+0x13a/0x3e0 [ 0.504627] but there are no more locks to release! [ 0.504627] [ 0.504627] other info that might help us debug this: [ 0.504627] 1 lock held by swapper/1: [ 0.504627] #0: (subsys mutex#4){+.+.+.}, at: [] subsys_interface_register+0x4f/0xe0 [ 0.504627] [ 0.504627] stack backtrace: [ 0.504627] CPU: 0 PID: 1 Comm: swapper Not tainted 3.11.0-rc6-next-20130819 #1 [ 0.504627] Hardware name: Bochs Bochs, BIOS Bochs 01/01/2007 [ 0.504627] ffffffff813d927a ffff88007f847c98 ffffffff814c062b ffff88007f847cc8 [ 0.504627] ffffffff81098bce ffff88007f847cf8 ffffffff81aadc30 ffffffff813d927a [ 0.504627] 00000000ffffffff ffff88007f847d68 ffffffff8109d0be 0000000000000006 [ 0.504627] Call Trace: [ 0.504627] [] ? cpufreq_add_dev+0x13a/0x3e0 [ 0.504627] [] dump_stack+0x19/0x1b [ 0.504627] [] print_unlock_imbalance_bug+0xfe/0x110 [ 0.504627] [] ? cpufreq_add_dev+0x13a/0x3e0 [ 0.504627] [] lock_release_non_nested+0x1ee/0x310 [ 0.504627] [] ? mark_held_locks+0xae/0x120 [ 0.504627] [] ? kfree+0xcb/0x1d0 [ 0.504627] [] ? cpufreq_policy_free+0x4a/0x60 [ 0.504627] [] ? cpufreq_add_dev+0x13a/0x3e0 [ 0.504627] [] lock_release+0xc4/0x250 [ 0.504627] [] up_read+0x23/0x40 [ 0.504627] [] cpufreq_add_dev+0x13a/0x3e0 [ 0.504627] [] subsys_interface_register+0x99/0xe0 [ 0.504627] [] ? cpufreq_gov_dbs_init+0x12/0x12 [ 0.504627] [] cpufreq_register_driver+0x9d/0x1d0 [ 0.504627] [] ? cpufreq_gov_dbs_init+0x12/0x12 [ 0.504627] [] acpi_cpufreq_init+0xfe/0x1f8 [ 0.504627] [] do_one_initcall+0xda/0x180 [ 0.504627] [] kernel_init_freeable+0x12c/0x1bb [ 0.504627] [] ? do_early_param+0x8c/0x8c [ 0.504627] [] ? rest_init+0x140/0x140 [ 0.504627] [] kernel_init+0xe/0xf0 [ 0.504627] [] ret_from_fork+0x7a/0xb0 [ 0.504627] [] ? rest_init+0x140/0x140 Signed-off-by: Li Zhong Acked-and-tested-by: Viresh Kumar Signed-off-by: Rafael J. Wysocki --- drivers/cpufreq/cpufreq.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'drivers/cpufreq/cpufreq.c') diff --git a/drivers/cpufreq/cpufreq.c b/drivers/cpufreq/cpufreq.c index 81ceea6ed630..5c75e3147a60 100644 --- a/drivers/cpufreq/cpufreq.c +++ b/drivers/cpufreq/cpufreq.c @@ -978,6 +978,7 @@ static int __cpufreq_add_dev(struct device *dev, struct subsys_interface *sif, cpufreq_cpu_put(policy); return 0; } +#endif if (!down_read_trylock(&cpufreq_rwsem)) return 0; @@ -994,7 +995,6 @@ static int __cpufreq_add_dev(struct device *dev, struct subsys_interface *sif, } } read_unlock_irqrestore(&cpufreq_driver_lock, flags); -#endif #endif if (frozen) -- cgit v1.2.3 From f73d39338444d9915c746403bd98b145ff9d2ba4 Mon Sep 17 00:00:00 2001 From: Viresh Kumar Date: Sat, 31 Aug 2013 17:53:40 +0530 Subject: cpufreq: don't allow governor limits to be changed when it is disabled __cpufreq_governor() returns with -EBUSY when governor is already stopped and we try to stop it again, but when it is stopped we must not allow calls to CPUFREQ_GOV_LIMITS event as well. This patch adds this check in __cpufreq_governor(). Reported-by: Stephen Boyd Signed-off-by: Viresh Kumar Signed-off-by: Rafael J. Wysocki --- drivers/cpufreq/cpufreq.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) (limited to 'drivers/cpufreq/cpufreq.c') diff --git a/drivers/cpufreq/cpufreq.c b/drivers/cpufreq/cpufreq.c index 5c75e3147a60..06a2496d2075 100644 --- a/drivers/cpufreq/cpufreq.c +++ b/drivers/cpufreq/cpufreq.c @@ -1692,8 +1692,9 @@ static int __cpufreq_governor(struct cpufreq_policy *policy, policy->cpu, event); mutex_lock(&cpufreq_governor_lock); - if ((!policy->governor_enabled && (event == CPUFREQ_GOV_STOP)) || - (policy->governor_enabled && (event == CPUFREQ_GOV_START))) { + if ((policy->governor_enabled && event == CPUFREQ_GOV_START) + || (!policy->governor_enabled + && (event == CPUFREQ_GOV_LIMITS || event == CPUFREQ_GOV_STOP))) { mutex_unlock(&cpufreq_governor_lock); return -EBUSY; } -- cgit v1.2.3 From 19c763031acb831a5ab9c1a701b7fedda073eb3f Mon Sep 17 00:00:00 2001 From: Viresh Kumar Date: Sat, 31 Aug 2013 17:48:23 +0530 Subject: cpufreq: serialize calls to __cpufreq_governor() We can't take a big lock around __cpufreq_governor() as this causes recursive locking for some cases. But calls to this routine must be serialized for every policy. Otherwise we can see some unpredictable events. For example, consider following scenario: __cpufreq_remove_dev() __cpufreq_governor(policy, CPUFREQ_GOV_STOP); policy->governor->governor(policy, CPUFREQ_GOV_STOP); cpufreq_governor_dbs() case CPUFREQ_GOV_STOP: mutex_destroy(&cpu_cdbs->timer_mutex) cpu_cdbs->cur_policy = NULL; store() __cpufreq_set_policy() __cpufreq_governor(policy, CPUFREQ_GOV_LIMITS); policy->governor->governor(policy, CPUFREQ_GOV_LIMITS); case CPUFREQ_GOV_LIMITS: mutex_lock(&cpu_cdbs->timer_mutex); <-- Warning (destroyed mutex) if (policy->max < cpu_cdbs->cur_policy->cur) <- cur_policy == NULL And so store() will eventually result in a crash if cur_policy is NULL at this point. Introduce an additional variable which would guarantee serialization here. Reported-by: Stephen Boyd Signed-off-by: Viresh Kumar Signed-off-by: Rafael J. Wysocki --- drivers/cpufreq/cpufreq.c | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-) (limited to 'drivers/cpufreq/cpufreq.c') diff --git a/drivers/cpufreq/cpufreq.c b/drivers/cpufreq/cpufreq.c index 06a2496d2075..7e6baa58a7f2 100644 --- a/drivers/cpufreq/cpufreq.c +++ b/drivers/cpufreq/cpufreq.c @@ -1692,13 +1692,15 @@ static int __cpufreq_governor(struct cpufreq_policy *policy, policy->cpu, event); mutex_lock(&cpufreq_governor_lock); - if ((policy->governor_enabled && event == CPUFREQ_GOV_START) + if (policy->governor_busy + || (policy->governor_enabled && event == CPUFREQ_GOV_START) || (!policy->governor_enabled && (event == CPUFREQ_GOV_LIMITS || event == CPUFREQ_GOV_STOP))) { mutex_unlock(&cpufreq_governor_lock); return -EBUSY; } + policy->governor_busy = true; if (event == CPUFREQ_GOV_STOP) policy->governor_enabled = false; else if (event == CPUFREQ_GOV_START) @@ -1727,6 +1729,9 @@ static int __cpufreq_governor(struct cpufreq_policy *policy, ((event == CPUFREQ_GOV_POLICY_EXIT) && !ret)) module_put(policy->governor->owner); + mutex_lock(&cpufreq_governor_lock); + policy->governor_busy = false; + mutex_unlock(&cpufreq_governor_lock); return ret; } -- cgit v1.2.3 From cedb70afd077b00bff7379042fdbf7eef32606c9 Mon Sep 17 00:00:00 2001 From: "Srivatsa S. Bhat" Date: Sat, 7 Sep 2013 01:23:09 +0530 Subject: cpufreq: Split __cpufreq_remove_dev() into two parts During CPU offline, the cpufreq core invokes __cpufreq_remove_dev() to perform work such as stopping the cpufreq governor, clearing the CPU from the policy structure etc, and finally cleaning up the kobject. There are certain subtle issues related to the kobject cleanup, and it would be much easier to deal with them if we separate that part from the rest of the cleanup-work in the CPU offline phase. So split the __cpufreq_remove_dev() function into 2 parts: one that handles the kobject cleanup, and the other that handles the rest of the work. Reported-by: Stephen Boyd Signed-off-by: Srivatsa S. Bhat Signed-off-by: Rafael J. Wysocki --- drivers/cpufreq/cpufreq.c | 65 ++++++++++++++++++++++++++++++++++++++--------- 1 file changed, 53 insertions(+), 12 deletions(-) (limited to 'drivers/cpufreq/cpufreq.c') diff --git a/drivers/cpufreq/cpufreq.c b/drivers/cpufreq/cpufreq.c index 7e6baa58a7f2..a33174e324d1 100644 --- a/drivers/cpufreq/cpufreq.c +++ b/drivers/cpufreq/cpufreq.c @@ -1141,22 +1141,14 @@ static int cpufreq_nominate_new_policy_cpu(struct cpufreq_policy *policy, return cpu_dev->id; } -/** - * __cpufreq_remove_dev - remove a CPU device - * - * Removes the cpufreq interface for a CPU device. - * Caller should already have policy_rwsem in write mode for this CPU. - * This routine frees the rwsem before returning. - */ -static int __cpufreq_remove_dev(struct device *dev, - struct subsys_interface *sif, bool frozen) +static int __cpufreq_remove_dev_prepare(struct device *dev, + struct subsys_interface *sif, + bool frozen) { unsigned int cpu = dev->id, cpus; int new_cpu, ret; unsigned long flags; struct cpufreq_policy *policy; - struct kobject *kobj; - struct completion *cmp; pr_debug("%s: unregistering CPU %u\n", __func__, cpu); @@ -1213,6 +1205,33 @@ static int __cpufreq_remove_dev(struct device *dev, } } + return 0; +} + +static int __cpufreq_remove_dev_finish(struct device *dev, + struct subsys_interface *sif, + bool frozen) +{ + unsigned int cpu = dev->id, cpus; + int ret; + unsigned long flags; + struct cpufreq_policy *policy; + struct kobject *kobj; + struct completion *cmp; + + read_lock_irqsave(&cpufreq_driver_lock, flags); + policy = per_cpu(cpufreq_cpu_data, cpu); + read_unlock_irqrestore(&cpufreq_driver_lock, flags); + + if (!policy) { + pr_debug("%s: No cpu_data found\n", __func__); + return -EINVAL; + } + + lock_policy_rwsem_read(cpu); + cpus = cpumask_weight(policy->cpus); + unlock_policy_rwsem_read(cpu); + /* If cpu is last user of policy, free policy */ if (cpus == 1) { if (cpufreq_driver->target) { @@ -1272,6 +1291,27 @@ static int __cpufreq_remove_dev(struct device *dev, return 0; } +/** + * __cpufreq_remove_dev - remove a CPU device + * + * Removes the cpufreq interface for a CPU device. + * Caller should already have policy_rwsem in write mode for this CPU. + * This routine frees the rwsem before returning. + */ +static inline int __cpufreq_remove_dev(struct device *dev, + struct subsys_interface *sif, + bool frozen) +{ + int ret; + + ret = __cpufreq_remove_dev_prepare(dev, sif, frozen); + + if (!ret) + ret = __cpufreq_remove_dev_finish(dev, sif, frozen); + + return ret; +} + static int cpufreq_remove_dev(struct device *dev, struct subsys_interface *sif) { unsigned int cpu = dev->id; @@ -2000,7 +2040,8 @@ static int cpufreq_cpu_callback(struct notifier_block *nfb, break; case CPU_DOWN_PREPARE: - __cpufreq_remove_dev(dev, NULL, frozen); + __cpufreq_remove_dev_prepare(dev, NULL, frozen); + __cpufreq_remove_dev_finish(dev, NULL, frozen); break; case CPU_DOWN_FAILED: -- cgit v1.2.3 From 1aee40ac9c86759c05f2ceb4523642b22fc8ea36 Mon Sep 17 00:00:00 2001 From: "Srivatsa S. Bhat" Date: Sat, 7 Sep 2013 01:23:27 +0530 Subject: cpufreq: Invoke __cpufreq_remove_dev_finish() after releasing cpu_hotplug.lock __cpufreq_remove_dev_finish() handles the kobject cleanup for a CPU going offline. But because we destroy the kobject towards the end of the CPU offline phase, there are certain race windows where a task can try to write to a cpufreq sysfs file (eg: using store_scaling_max_freq()) while we are taking that CPU offline, and this can bump up the kobject refcount, which in turn might hinder the CPU offline task from running to completion. (It can also cause other more serious problems such as trying to acquire a destroyed timer-mutex etc., depending on the exact stage of the cleanup at which the task managed to take a new refcount). To fix the race window, we will need to synchronize those store_*() call-sites with CPU hotplug, using get_online_cpus()/put_online_cpus(). However, that in turn can cause a total deadlock because it can end up waiting for the CPU offline task to complete, with incremented refcount! Write to sysfs CPU offline task -------------- ---------------- kobj_refcnt++ Acquire cpu_hotplug.lock get_online_cpus(); Wait for kobj_refcnt to drop to zero **DEADLOCK** A simple way to avoid this problem is to perform the kobject cleanup in the CPU offline path, with the cpu_hotplug.lock *released*. That is, we can perform the wait-for-kobj-refcnt-to-drop as well as the subsequent cleanup in the CPU_POST_DEAD stage of CPU offline, which is run with cpu_hotplug.lock released. Doing this helps us avoid deadlocks due to holding kobject refcounts and waiting on each other on the cpu_hotplug.lock. (Note: We can't move all of the cpufreq CPU offline steps to the CPU_POST_DEAD stage, because certain things such as stopping the governors have to be done before the outgoing CPU is marked offline. So retain those parts in the CPU_DOWN_PREPARE stage itself). Reported-by: Stephen Boyd Signed-off-by: Srivatsa S. Bhat Signed-off-by: Rafael J. Wysocki --- drivers/cpufreq/cpufreq.c | 3 +++ 1 file changed, 3 insertions(+) (limited to 'drivers/cpufreq/cpufreq.c') diff --git a/drivers/cpufreq/cpufreq.c b/drivers/cpufreq/cpufreq.c index a33174e324d1..34999fc3216f 100644 --- a/drivers/cpufreq/cpufreq.c +++ b/drivers/cpufreq/cpufreq.c @@ -2041,6 +2041,9 @@ static int cpufreq_cpu_callback(struct notifier_block *nfb, case CPU_DOWN_PREPARE: __cpufreq_remove_dev_prepare(dev, NULL, frozen); + break; + + case CPU_POST_DEAD: __cpufreq_remove_dev_finish(dev, NULL, frozen); break; -- cgit v1.2.3 From 4f750c930822b92df74327a4d1364eff87701360 Mon Sep 17 00:00:00 2001 From: "Srivatsa S. Bhat" Date: Sat, 7 Sep 2013 01:23:43 +0530 Subject: cpufreq: Synchronize the cpufreq store_*() routines with CPU hotplug The functions that are used to write to cpufreq sysfs files (such as store_scaling_max_freq()) are not hotplug safe. They can race with CPU hotplug tasks and lead to problems such as trying to acquire an already destroyed timer-mutex etc. Eg: __cpufreq_remove_dev() __cpufreq_governor(policy, CPUFREQ_GOV_STOP); policy->governor->governor(policy, CPUFREQ_GOV_STOP); cpufreq_governor_dbs() case CPUFREQ_GOV_STOP: mutex_destroy(&cpu_cdbs->timer_mutex) cpu_cdbs->cur_policy = NULL; store() __cpufreq_set_policy() __cpufreq_governor(policy, CPUFREQ_GOV_LIMITS); policy->governor->governor(policy, CPUFREQ_GOV_LIMITS); case CPUFREQ_GOV_LIMITS: mutex_lock(&cpu_cdbs->timer_mutex); <-- Warning (destroyed mutex) if (policy->max < cpu_cdbs->cur_policy->cur) <- cur_policy == NULL So use get_online_cpus()/put_online_cpus() in the store_*() functions, to synchronize with CPU hotplug. However, there is an additional point to note here: some parts of the CPU teardown in the cpufreq subsystem are done in the CPU_POST_DEAD stage, with cpu_hotplug.lock *released*. So, using the get/put_online_cpus() functions alone is insufficient; we should also ensure that we don't race with those latter steps in the hotplug sequence. We can easily achieve this by checking if the CPU is online before proceeding with the store, since the CPU would have been marked offline by the time the CPU_POST_DEAD notifiers are executed. Reported-by: Stephen Boyd Signed-off-by: Srivatsa S. Bhat Signed-off-by: Rafael J. Wysocki --- drivers/cpufreq/cpufreq.c | 11 +++++++++-- 1 file changed, 9 insertions(+), 2 deletions(-) (limited to 'drivers/cpufreq/cpufreq.c') diff --git a/drivers/cpufreq/cpufreq.c b/drivers/cpufreq/cpufreq.c index 34999fc3216f..cf016584b4ac 100644 --- a/drivers/cpufreq/cpufreq.c +++ b/drivers/cpufreq/cpufreq.c @@ -694,8 +694,13 @@ static ssize_t store(struct kobject *kobj, struct attribute *attr, struct freq_attr *fattr = to_attr(attr); ssize_t ret = -EINVAL; + get_online_cpus(); + + if (!cpu_online(policy->cpu)) + goto unlock; + if (!down_read_trylock(&cpufreq_rwsem)) - goto exit; + goto unlock; if (lock_policy_rwsem_write(policy->cpu) < 0) goto up_read; @@ -709,7 +714,9 @@ static ssize_t store(struct kobject *kobj, struct attribute *attr, up_read: up_read(&cpufreq_rwsem); -exit: +unlock: + put_online_cpus(); + return ret; } -- cgit v1.2.3 From 56d07db274b7b15ca38b60ea4a762d40de093000 Mon Sep 17 00:00:00 2001 From: "Srivatsa S. Bhat" Date: Sat, 7 Sep 2013 01:23:55 +0530 Subject: cpufreq: Remove temporary fix for race between CPU hotplug and sysfs-writes Commit "cpufreq: serialize calls to __cpufreq_governor()" had been a temporary and partial solution to the race condition between writing to a cpufreq sysfs file and taking a CPU offline. Now that we have a proper and complete solution to that problem, remove the temporary fix. Signed-off-by: Srivatsa S. Bhat Signed-off-by: Rafael J. Wysocki --- drivers/cpufreq/cpufreq.c | 7 +------ 1 file changed, 1 insertion(+), 6 deletions(-) (limited to 'drivers/cpufreq/cpufreq.c') diff --git a/drivers/cpufreq/cpufreq.c b/drivers/cpufreq/cpufreq.c index cf016584b4ac..2863214c5381 100644 --- a/drivers/cpufreq/cpufreq.c +++ b/drivers/cpufreq/cpufreq.c @@ -1739,15 +1739,13 @@ static int __cpufreq_governor(struct cpufreq_policy *policy, policy->cpu, event); mutex_lock(&cpufreq_governor_lock); - if (policy->governor_busy - || (policy->governor_enabled && event == CPUFREQ_GOV_START) + if ((policy->governor_enabled && event == CPUFREQ_GOV_START) || (!policy->governor_enabled && (event == CPUFREQ_GOV_LIMITS || event == CPUFREQ_GOV_STOP))) { mutex_unlock(&cpufreq_governor_lock); return -EBUSY; } - policy->governor_busy = true; if (event == CPUFREQ_GOV_STOP) policy->governor_enabled = false; else if (event == CPUFREQ_GOV_START) @@ -1776,9 +1774,6 @@ static int __cpufreq_governor(struct cpufreq_policy *policy, ((event == CPUFREQ_GOV_POLICY_EXIT) && !ret)) module_put(policy->governor->owner); - mutex_lock(&cpufreq_governor_lock); - policy->governor_busy = false; - mutex_unlock(&cpufreq_governor_lock); return ret; } -- cgit v1.2.3 From 5136fa56582beadb7fa71eb30bc79148bfcba5c1 Mon Sep 17 00:00:00 2001 From: "Srivatsa S. Bhat" Date: Sat, 7 Sep 2013 01:24:06 +0530 Subject: cpufreq: Use signed type for 'ret' variable, to store negative error values There are places where the variable 'ret' is declared as unsigned int and then used to store negative return values such as -EINVAL. Fix them by declaring the variable as a signed quantity. Signed-off-by: Srivatsa S. Bhat Signed-off-by: Rafael J. Wysocki --- drivers/cpufreq/cpufreq.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) (limited to 'drivers/cpufreq/cpufreq.c') diff --git a/drivers/cpufreq/cpufreq.c b/drivers/cpufreq/cpufreq.c index 2863214c5381..73d53d5a16ee 100644 --- a/drivers/cpufreq/cpufreq.c +++ b/drivers/cpufreq/cpufreq.c @@ -437,7 +437,7 @@ static int __cpufreq_set_policy(struct cpufreq_policy *policy, static ssize_t store_##file_name \ (struct cpufreq_policy *policy, const char *buf, size_t count) \ { \ - unsigned int ret; \ + int ret; \ struct cpufreq_policy new_policy; \ \ ret = cpufreq_get_policy(&new_policy, policy->cpu); \ @@ -490,7 +490,7 @@ static ssize_t show_scaling_governor(struct cpufreq_policy *policy, char *buf) static ssize_t store_scaling_governor(struct cpufreq_policy *policy, const char *buf, size_t count) { - unsigned int ret; + int ret; char str_governor[16]; struct cpufreq_policy new_policy; -- cgit v1.2.3 From 798282a8718347b04a2f0a4bae7d775c48c6bcb9 Mon Sep 17 00:00:00 2001 From: "Rafael J. Wysocki" Date: Tue, 10 Sep 2013 02:54:50 +0200 Subject: Revert "cpufreq: make sure frequency transitions are serialized" Commit 7c30ed5 (cpufreq: make sure frequency transitions are serialized) attempted to serialize frequency transitions by adding checks to the CPUFREQ_PRECHANGE and CPUFREQ_POSTCHANGE notifications. However, it assumed that the notifications will always originate from the driver's .target() callback, but they also can be triggered by cpufreq_out_of_sync() and that leads to warnings like this on some systems: WARNING: CPU: 0 PID: 14543 at drivers/cpufreq/cpufreq.c:317 __cpufreq_notify_transition+0x238/0x260() In middle of another frequency transition accompanied by a call trace similar to this one: [] dump_stack+0x46/0x58 [] warn_slowpath_common+0x8c/0xc0 [] ? acpi_cpufreq_target+0x320/0x320 [] warn_slowpath_fmt+0x46/0x50 [] __cpufreq_notify_transition+0x238/0x260 [] cpufreq_notify_transition+0x3e/0x70 [] cpufreq_out_of_sync+0x6d/0xb0 [] cpufreq_update_policy+0x10c/0x160 [] ? cpufreq_update_policy+0x160/0x160 [] cpufreq_set_cur_state+0x8c/0xb5 [] processor_set_cur_state+0xa3/0xcf [] thermal_cdev_update+0x9c/0xb0 [] step_wise_throttle+0x5a/0x90 [] handle_thermal_trip+0x4f/0x140 [] thermal_zone_device_update+0x57/0xa0 [] acpi_thermal_check+0x2e/0x30 [] acpi_thermal_notify+0x40/0xdc [] acpi_device_notify+0x19/0x1b [] acpi_ev_notify_dispatch+0x41/0x5c [] acpi_os_execute_deferred+0x25/0x32 [] process_one_work+0x170/0x4a0 [] worker_thread+0x121/0x390 [] ? manage_workers.isra.20+0x170/0x170 [] kthread+0xc0/0xd0 [] ? flush_kthread_worker+0xb0/0xb0 [] ret_from_fork+0x7c/0xb0 [] ? flush_kthread_worker+0xb0/0xb0 For this reason, revert commit 7c30ed5 along with the fix 266c13d (cpufreq: Fix serialization of frequency transitions) on top of it and we will revisit the serialization problem later. Reported-by: Alessandro Bono Signed-off-by: Rafael J. Wysocki --- drivers/cpufreq/cpufreq.c | 15 --------------- 1 file changed, 15 deletions(-) (limited to 'drivers/cpufreq/cpufreq.c') diff --git a/drivers/cpufreq/cpufreq.c b/drivers/cpufreq/cpufreq.c index 73d53d5a16ee..5a64f66d36e0 100644 --- a/drivers/cpufreq/cpufreq.c +++ b/drivers/cpufreq/cpufreq.c @@ -280,13 +280,6 @@ static void __cpufreq_notify_transition(struct cpufreq_policy *policy, switch (state) { case CPUFREQ_PRECHANGE: - if (WARN(policy->transition_ongoing == - cpumask_weight(policy->cpus), - "In middle of another frequency transition\n")) - return; - - policy->transition_ongoing++; - /* detect if the driver reported a value as "old frequency" * which is not equal to what the cpufreq core thinks is * "old frequency". @@ -306,12 +299,6 @@ static void __cpufreq_notify_transition(struct cpufreq_policy *policy, break; case CPUFREQ_POSTCHANGE: - if (WARN(!policy->transition_ongoing, - "No frequency transition in progress\n")) - return; - - policy->transition_ongoing--; - adjust_jiffies(CPUFREQ_POSTCHANGE, freqs); pr_debug("FREQ: %lu - CPU: %lu", (unsigned long)freqs->new, (unsigned long)freqs->cpu); @@ -1657,8 +1644,6 @@ int __cpufreq_driver_target(struct cpufreq_policy *policy, if (cpufreq_disabled()) return -ENODEV; - if (policy->transition_ongoing) - return -EBUSY; /* Make sure that target_freq is within supported range */ if (target_freq > policy->max) -- cgit v1.2.3 From 0d66b91ebff49841f607a3c079984c907c8a4199 Mon Sep 17 00:00:00 2001 From: "Srivatsa S. Bhat" Date: Thu, 12 Sep 2013 01:42:59 +0530 Subject: cpufreq: Fix crash in cpufreq-stats during suspend/resume Stephen Warren reported that the cpufreq-stats code hits a NULL pointer dereference during the second attempt to suspend a system. He also pin-pointed the problem to commit 5302c3f "cpufreq: Perform light-weight init/teardown during suspend/resume". That commit actually ensured that the cpufreq-stats table and the cpufreq-stats sysfs entries are *not* torn down (ie., not freed) during suspend/resume, which makes it all the more surprising. However, it turns out that the root-cause is not that we access an already freed memory, but that the reference to the allocated memory gets moved around and we lose track of that during resume, leading to the reported crash in a subsequent suspend attempt. In the suspend path, during CPU offline, the value of policy->cpu is updated by choosing one of the surviving CPUs in that policy, as long as there is atleast one CPU in that policy. And cpufreq_stats_update_policy_cpu() is invoked to update the reference to the stats structure by assigning it to the new CPU. However, in the resume path, during CPU online, we end up assigning a fresh CPU as the policy->cpu, without letting cpufreq-stats know about this. Thus the reference to the stats structure remains (incorrectly) associated with the old CPU. So, in a subsequent suspend attempt, during CPU offline, we end up accessing an incorrect location to get the stats structure, which eventually leads to the NULL pointer dereference. Fix this by letting cpufreq-stats know about the update of the policy->cpu during CPU online in the resume path. (Also, move the update_policy_cpu() function higher up in the file, so that __cpufreq_add_dev() can invoke it). Reported-and-tested-by: Stephen Warren Signed-off-by: Srivatsa S. Bhat Signed-off-by: Rafael J. Wysocki --- drivers/cpufreq/cpufreq.c | 37 ++++++++++++++++++++++++------------- 1 file changed, 24 insertions(+), 13 deletions(-) (limited to 'drivers/cpufreq/cpufreq.c') diff --git a/drivers/cpufreq/cpufreq.c b/drivers/cpufreq/cpufreq.c index 5a64f66d36e0..62bdb955ea56 100644 --- a/drivers/cpufreq/cpufreq.c +++ b/drivers/cpufreq/cpufreq.c @@ -947,6 +947,18 @@ static void cpufreq_policy_free(struct cpufreq_policy *policy) kfree(policy); } +static void update_policy_cpu(struct cpufreq_policy *policy, unsigned int cpu) +{ + policy->last_cpu = policy->cpu; + policy->cpu = cpu; + +#ifdef CONFIG_CPU_FREQ_TABLE + cpufreq_frequency_table_update_policy_cpu(policy); +#endif + blocking_notifier_call_chain(&cpufreq_policy_notifier_list, + CPUFREQ_UPDATE_POLICY_CPU, policy); +} + static int __cpufreq_add_dev(struct device *dev, struct subsys_interface *sif, bool frozen) { @@ -1000,7 +1012,18 @@ static int __cpufreq_add_dev(struct device *dev, struct subsys_interface *sif, if (!policy) goto nomem_out; - policy->cpu = cpu; + + /* + * In the resume path, since we restore a saved policy, the assignment + * to policy->cpu is like an update of the existing policy, rather than + * the creation of a brand new one. So we need to perform this update + * by invoking update_policy_cpu(). + */ + if (frozen && cpu != policy->cpu) + update_policy_cpu(policy, cpu); + else + policy->cpu = cpu; + policy->governor = CPUFREQ_DEFAULT_GOVERNOR; cpumask_copy(policy->cpus, cpumask_of(cpu)); @@ -1092,18 +1115,6 @@ static int cpufreq_add_dev(struct device *dev, struct subsys_interface *sif) return __cpufreq_add_dev(dev, sif, false); } -static void update_policy_cpu(struct cpufreq_policy *policy, unsigned int cpu) -{ - policy->last_cpu = policy->cpu; - policy->cpu = cpu; - -#ifdef CONFIG_CPU_FREQ_TABLE - cpufreq_frequency_table_update_policy_cpu(policy); -#endif - blocking_notifier_call_chain(&cpufreq_policy_notifier_list, - CPUFREQ_UPDATE_POLICY_CPU, policy); -} - static int cpufreq_nominate_new_policy_cpu(struct cpufreq_policy *policy, unsigned int old_cpu, bool frozen) { -- cgit v1.2.3 From 61173f256a3bebfbd09b4bd2c164dde378614091 Mon Sep 17 00:00:00 2001 From: "Srivatsa S. Bhat" Date: Thu, 12 Sep 2013 01:43:25 +0530 Subject: cpufreq: Restructure if/else block to avoid unintended behavior In __cpufreq_remove_dev_prepare(), the code which decides whether to remove the sysfs link or nominate a new policy cpu, is governed by an if/else block with a rather complex set of conditionals. Worse, they harbor a subtlety which leads to certain unintended behavior. The code looks like this: if (cpu != policy->cpu && !frozen) { sysfs_remove_link(&dev->kobj, "cpufreq"); } else if (cpus > 1) { new_cpu = cpufreq_nominate_new_policy_cpu(...); ... update_policy_cpu(..., new_cpu); } The original intention was: If the CPU going offline is not policy->cpu, just remove the link. On the other hand, if the CPU going offline is the policy->cpu itself, handover the policy->cpu job to some other surviving CPU in that policy. But because the 'if' condition also includes the 'frozen' check, now there are *two* possibilities by which we can enter the 'else' block: 1. cpu == policy->cpu (intended) 2. cpu != policy->cpu && frozen (unintended) Due to the second (unintended) scenario, we end up spuriously nominating a CPU as the policy->cpu, even when the existing policy->cpu is alive and well. This can cause problems further down the line, especially when we end up nominating the same policy->cpu as the new one (ie., old == new), because it totally confuses update_policy_cpu(). To avoid this mess, restructure the if/else block to only do what was originally intended, and thus prevent any unwelcome surprises. Signed-off-by: Srivatsa S. Bhat Tested-by: Stephen Warren Signed-off-by: Rafael J. Wysocki --- drivers/cpufreq/cpufreq.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) (limited to 'drivers/cpufreq/cpufreq.c') diff --git a/drivers/cpufreq/cpufreq.c b/drivers/cpufreq/cpufreq.c index 62bdb955ea56..247842b2ee2d 100644 --- a/drivers/cpufreq/cpufreq.c +++ b/drivers/cpufreq/cpufreq.c @@ -1193,8 +1193,9 @@ static int __cpufreq_remove_dev_prepare(struct device *dev, cpumask_clear_cpu(cpu, policy->cpus); unlock_policy_rwsem_write(cpu); - if (cpu != policy->cpu && !frozen) { - sysfs_remove_link(&dev->kobj, "cpufreq"); + if (cpu != policy->cpu) { + if (!frozen) + sysfs_remove_link(&dev->kobj, "cpufreq"); } else if (cpus > 1) { new_cpu = cpufreq_nominate_new_policy_cpu(policy, cpu, frozen); -- cgit v1.2.3 From cb38ed5cf1c4fdb7454e4b48fb70c396f5acfb21 Mon Sep 17 00:00:00 2001 From: "Srivatsa S. Bhat" Date: Thu, 12 Sep 2013 01:43:42 +0530 Subject: cpufreq: Prevent problems in update_policy_cpu() if last_cpu == new_cpu If update_policy_cpu() is invoked with the existing policy->cpu itself as the new-cpu parameter, then a lot of things can go terribly wrong. In its present form, update_policy_cpu() always assumes that the new-cpu is different from policy->cpu and invokes other functions to perform their respective updates. And those functions implement the actual update like this: per_cpu(..., new_cpu) = per_cpu(..., last_cpu); per_cpu(..., last_cpu) = NULL; Thus, when new_cpu == last_cpu, the final NULL assignment makes the per-cpu references vanish into thin air! (memory leak). From there, it leads to more problems: cpufreq_stats_create_table() now doesn't find the per-cpu reference and hence tries to create a new sysfs-group; but sysfs already had created the group earlier, so it complains that it cannot create a duplicate filename. In short, the repercussions of a rather innocuous invocation of update_policy_cpu() can turn out to be pretty nasty. Ideally update_policy_cpu() should handle this situation (new == last) gracefully, and not lead to such severe problems. So fix it by adding an appropriate check. Signed-off-by: Srivatsa S. Bhat Tested-by: Stephen Warren Signed-off-by: Rafael J. Wysocki --- drivers/cpufreq/cpufreq.c | 3 +++ 1 file changed, 3 insertions(+) (limited to 'drivers/cpufreq/cpufreq.c') diff --git a/drivers/cpufreq/cpufreq.c b/drivers/cpufreq/cpufreq.c index 247842b2ee2d..d32040cc1c46 100644 --- a/drivers/cpufreq/cpufreq.c +++ b/drivers/cpufreq/cpufreq.c @@ -949,6 +949,9 @@ static void cpufreq_policy_free(struct cpufreq_policy *policy) static void update_policy_cpu(struct cpufreq_policy *policy, unsigned int cpu) { + if (cpu == policy->cpu) + return; + policy->last_cpu = policy->cpu; policy->cpu = cpu; -- cgit v1.2.3 From 44871c9c7f7963f8869dd8bc9620221c9e9db153 Mon Sep 17 00:00:00 2001 From: Lan Tianyu Date: Wed, 11 Sep 2013 15:05:05 +0800 Subject: cpufreq: Acquire the lock in cpufreq_policy_restore() for reading In cpufreq_policy_restore() before system suspend policy is read from percpu's cpufreq_cpu_data_fallback. It's a read operation rather than a write one, so take the lock for reading in there. Signed-off-by: Lan Tianyu Reviewed-by: Srivatsa S. Bhat Acked-by: Viresh Kumar Signed-off-by: Rafael J. Wysocki --- drivers/cpufreq/cpufreq.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) (limited to 'drivers/cpufreq/cpufreq.c') diff --git a/drivers/cpufreq/cpufreq.c b/drivers/cpufreq/cpufreq.c index d32040cc1c46..43c24aa756f6 100644 --- a/drivers/cpufreq/cpufreq.c +++ b/drivers/cpufreq/cpufreq.c @@ -906,11 +906,11 @@ static struct cpufreq_policy *cpufreq_policy_restore(unsigned int cpu) struct cpufreq_policy *policy; unsigned long flags; - write_lock_irqsave(&cpufreq_driver_lock, flags); + read_lock_irqsave(&cpufreq_driver_lock, flags); policy = per_cpu(cpufreq_cpu_data_fallback, cpu); - write_unlock_irqrestore(&cpufreq_driver_lock, flags); + read_unlock_irqrestore(&cpufreq_driver_lock, flags); return policy; } -- cgit v1.2.3 From 9c8f1ee40b6368e6b2775c9c9f816e2a5dca3c07 Mon Sep 17 00:00:00 2001 From: Viresh Kumar Date: Thu, 12 Sep 2013 17:06:33 +0530 Subject: cpufreq: Clear policy->cpus bits in __cpufreq_remove_dev_finish() This broke after a recent change "cedb70a cpufreq: Split __cpufreq_remove_dev() into two parts" from Srivatsa. Consider a scenario where we have two CPUs in a policy (0 & 1) and we are removing CPU 1. On the call to __cpufreq_remove_dev_prepare() we have cleared 1 from policy->cpus and now on a call to __cpufreq_remove_dev_finish() we read cpumask_weight of policy->cpus, which will come as 1 and this code will behave as if we are removing the last CPU from policy :) Fix it by clearing the CPU mask in __cpufreq_remove_dev_finish() instead of __cpufreq_remove_dev_prepare(). Tested-by: Stephen Warren Reviewed-by: Srivatsa S. Bhat Signed-off-by: Viresh Kumar Signed-off-by: Rafael J. Wysocki --- drivers/cpufreq/cpufreq.c | 16 ++++++++-------- 1 file changed, 8 insertions(+), 8 deletions(-) (limited to 'drivers/cpufreq/cpufreq.c') diff --git a/drivers/cpufreq/cpufreq.c b/drivers/cpufreq/cpufreq.c index 43c24aa756f6..dbfe219667d3 100644 --- a/drivers/cpufreq/cpufreq.c +++ b/drivers/cpufreq/cpufreq.c @@ -1125,7 +1125,7 @@ static int cpufreq_nominate_new_policy_cpu(struct cpufreq_policy *policy, int ret; /* first sibling now owns the new sysfs dir */ - cpu_dev = get_cpu_device(cpumask_first(policy->cpus)); + cpu_dev = get_cpu_device(cpumask_any_but(policy->cpus, old_cpu)); /* Don't touch sysfs files during light-weight tear-down */ if (frozen) @@ -1189,12 +1189,9 @@ static int __cpufreq_remove_dev_prepare(struct device *dev, policy->governor->name, CPUFREQ_NAME_LEN); #endif - WARN_ON(lock_policy_rwsem_write(cpu)); + lock_policy_rwsem_read(cpu); cpus = cpumask_weight(policy->cpus); - - if (cpus > 1) - cpumask_clear_cpu(cpu, policy->cpus); - unlock_policy_rwsem_write(cpu); + unlock_policy_rwsem_read(cpu); if (cpu != policy->cpu) { if (!frozen) @@ -1237,9 +1234,12 @@ static int __cpufreq_remove_dev_finish(struct device *dev, return -EINVAL; } - lock_policy_rwsem_read(cpu); + WARN_ON(lock_policy_rwsem_write(cpu)); cpus = cpumask_weight(policy->cpus); - unlock_policy_rwsem_read(cpu); + + if (cpus > 1) + cpumask_clear_cpu(cpu, policy->cpus); + unlock_policy_rwsem_write(cpu); /* If cpu is last user of policy, free policy */ if (cpus == 1) { -- cgit v1.2.3 From 8efd57657d8ef666810b55e609da72de92314dc4 Mon Sep 17 00:00:00 2001 From: Viresh Kumar Date: Tue, 17 Sep 2013 10:22:11 +0530 Subject: cpufreq: unlock correct rwsem while updating policy->cpu Current code looks like this: WARN_ON(lock_policy_rwsem_write(cpu)); update_policy_cpu(policy, new_cpu); unlock_policy_rwsem_write(cpu); {lock|unlock}_policy_rwsem_write(cpu) takes/releases policy->cpu's rwsem. Because cpu is changing with the call to update_policy_cpu(), the unlock_policy_rwsem_write() will release the incorrect lock. The right solution would be to release the same lock as was taken earlier. Also update_policy_cpu() was also called from cpufreq_add_dev() without any locks and so its better if we move this locking to inside update_policy_cpu(). This patch fixes a regression introduced in 3.12 by commit f9ba680d23 (cpufreq: Extract the handover of policy cpu to a helper function). Reported-and-tested-by: Jon Medhurst Signed-off-by: Viresh Kumar Signed-off-by: Rafael J. Wysocki --- drivers/cpufreq/cpufreq.c | 13 +++++++++++-- 1 file changed, 11 insertions(+), 2 deletions(-) (limited to 'drivers/cpufreq/cpufreq.c') diff --git a/drivers/cpufreq/cpufreq.c b/drivers/cpufreq/cpufreq.c index dbfe219667d3..82ecbe39dfb0 100644 --- a/drivers/cpufreq/cpufreq.c +++ b/drivers/cpufreq/cpufreq.c @@ -952,9 +952,20 @@ static void update_policy_cpu(struct cpufreq_policy *policy, unsigned int cpu) if (cpu == policy->cpu) return; + /* + * Take direct locks as lock_policy_rwsem_write wouldn't work here. + * Also lock for last cpu is enough here as contention will happen only + * after policy->cpu is changed and after it is changed, other threads + * will try to acquire lock for new cpu. And policy is already updated + * by then. + */ + down_write(&per_cpu(cpu_policy_rwsem, policy->cpu)); + policy->last_cpu = policy->cpu; policy->cpu = cpu; + up_write(&per_cpu(cpu_policy_rwsem, policy->last_cpu)); + #ifdef CONFIG_CPU_FREQ_TABLE cpufreq_frequency_table_update_policy_cpu(policy); #endif @@ -1200,9 +1211,7 @@ static int __cpufreq_remove_dev_prepare(struct device *dev, new_cpu = cpufreq_nominate_new_policy_cpu(policy, cpu, frozen); if (new_cpu >= 0) { - WARN_ON(lock_policy_rwsem_write(cpu)); update_policy_cpu(policy, new_cpu); - unlock_policy_rwsem_write(cpu); if (!frozen) { pr_debug("%s: policy Kobject moved to cpu: %d " -- cgit v1.2.3 From 4dea5806d332f91d640d99943db99a5539e832c3 Mon Sep 17 00:00:00 2001 From: Yinghai Lu Date: Wed, 18 Sep 2013 21:05:20 -0700 Subject: cpufreq: return EEXIST instead of EBUSY for second registering On systems that support intel_pstate, acpi_cpufreq fails to load, and udev keeps trying until trace gets filled up and kernel crashes. The root cause is driver return ret from cpufreq_register_driver(), because when some other driver takes over before, it will return EBUSY and then udev will keep trying ... cpufreq_register_driver() should return EEXIST instead so that the system can boot without appending intel_pstate=disable and still use intel_pstate. Signed-off-by: Yinghai Lu Acked-by: Viresh Kumar Signed-off-by: Rafael J. Wysocki --- drivers/cpufreq/cpufreq.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'drivers/cpufreq/cpufreq.c') diff --git a/drivers/cpufreq/cpufreq.c b/drivers/cpufreq/cpufreq.c index 82ecbe39dfb0..89b3c52cd5c3 100644 --- a/drivers/cpufreq/cpufreq.c +++ b/drivers/cpufreq/cpufreq.c @@ -2104,7 +2104,7 @@ int cpufreq_register_driver(struct cpufreq_driver *driver_data) write_lock_irqsave(&cpufreq_driver_lock, flags); if (cpufreq_driver) { write_unlock_irqrestore(&cpufreq_driver_lock, flags); - return -EBUSY; + return -EEXIST; } cpufreq_driver = driver_data; write_unlock_irqrestore(&cpufreq_driver_lock, flags); -- cgit v1.2.3 From 26ca8694344af4c833d22590c5b77d6b9cff0722 Mon Sep 17 00:00:00 2001 From: Viresh Kumar Date: Fri, 20 Sep 2013 22:37:31 +0530 Subject: cpufreq: check cpufreq driver is valid and cpufreq isn't disabled in cpufreq_get() cpufreq_get() can be called from external drivers which might not be aware if cpufreq driver is registered or not. And so we should actually check if cpufreq driver is registered or not and also if cpufreq is active or disabled, at the beginning of cpufreq_get(). Otherwise call to lock_policy_rwsem_read() might hit BUG_ON(!policy). Reported-and-tested-by: Linus Walleij Signed-off-by: Viresh Kumar Reviewed-by: Srivatsa S. Bhat Signed-off-by: Rafael J. Wysocki --- drivers/cpufreq/cpufreq.c | 3 +++ 1 file changed, 3 insertions(+) (limited to 'drivers/cpufreq/cpufreq.c') diff --git a/drivers/cpufreq/cpufreq.c b/drivers/cpufreq/cpufreq.c index 89b3c52cd5c3..04548f7023af 100644 --- a/drivers/cpufreq/cpufreq.c +++ b/drivers/cpufreq/cpufreq.c @@ -1460,6 +1460,9 @@ unsigned int cpufreq_get(unsigned int cpu) { unsigned int ret_freq = 0; + if (cpufreq_disabled() || !cpufreq_driver) + return -ENOENT; + if (!down_read_trylock(&cpufreq_rwsem)) return 0; -- cgit v1.2.3