From ead18c23c263374ed098a7d955b29b4a466d4573 Mon Sep 17 00:00:00 2001 From: Lukas Wunner Date: Sat, 10 Feb 2018 19:27:12 +0100 Subject: driver core: Introduce device links reference counting If device_link_add() is invoked multiple times with the same supplier and consumer combo, it will create the link on first addition and return a pointer to the already existing link on all subsequent additions. The semantics for device_link_del() are quite different, it deletes the link unconditionally, so multiple invocations are not allowed. In other words, this snippet ... struct device *dev1, *dev2; struct device_link *link1, *link2; link1 = device_link_add(dev1, dev2, 0); link2 = device_link_add(dev1, dev2, 0); device_link_del(link1); device_link_del(link2); ... causes the following crash: WARNING: CPU: 4 PID: 2686 at drivers/base/power/runtime.c:1611 pm_runtime_drop_link+0x40/0x50 [...] list_del corruption, 0000000039b800a4->prev is LIST_POISON2 (00000000ecf79852) kernel BUG at lib/list_debug.c:50! The issue isn't as arbitrary as it may seem: Imagine a device link which is added in both the supplier's and the consumer's ->probe hook. The two drivers can't just call device_link_del() in their ->remove hook without coordination. Fix by counting multiple additions and dropping the device link only when the last addition is unwound. Signed-off-by: Lukas Wunner [ rjw: Subject ] Signed-off-by: Rafael J. Wysocki --- include/linux/device.h | 2 ++ 1 file changed, 2 insertions(+) (limited to 'include/linux') diff --git a/include/linux/device.h b/include/linux/device.h index b093405ed525..abf952c82c6d 100644 --- a/include/linux/device.h +++ b/include/linux/device.h @@ -769,6 +769,7 @@ enum device_link_state { * @status: The state of the link (with respect to the presence of drivers). * @flags: Link flags. * @rpm_active: Whether or not the consumer device is runtime-PM-active. + * @kref: Count repeated addition of the same link. * @rcu_head: An RCU head to use for deferred execution of SRCU callbacks. */ struct device_link { @@ -779,6 +780,7 @@ struct device_link { enum device_link_state status; u32 flags; bool rpm_active; + struct kref kref; #ifdef CONFIG_SRCU struct rcu_head rcu_head; #endif -- cgit From d417e0691ac00d35c4e6b90fc3fc85631a7865ad Mon Sep 17 00:00:00 2001 From: Viresh Kumar Date: Thu, 22 Feb 2018 11:29:44 +0530 Subject: cpufreq: Validate frequency table in the core By design, cpufreq drivers are responsible for calling cpufreq_frequency_table_cpuinfo() from their ->init() callbacks to validate the frequency table. However, if a cpufreq driver is buggy and fails to do so properly, it lead to unexpected behavior of the driver or the cpufreq core at a later point in time. It would be better if the core could validate the frequency table during driver initialization. To that end, introduce cpufreq_table_validate_and_sort() and make the cpufreq core call it right after invoking the ->init() callback of the driver and destroy the cpufreq policy if the table is invalid. For the time being the validation of the table happens twice, once from the driver and then from the core. The individual drivers will be updated separately to drop table validation if they don't need it for other reasons. The frequency table is marked "sorted" or "unsorted" by the new helper now instead of in cpufreq_table_validate_and_show(), as it should only be done after validating the table (which the drivers won't do going forward). Signed-off-by: Viresh Kumar [ rjw: Subject/changelog ] Signed-off-by: Rafael J. Wysocki --- include/linux/cpufreq.h | 1 + 1 file changed, 1 insertion(+) (limited to 'include/linux') diff --git a/include/linux/cpufreq.h b/include/linux/cpufreq.h index 21e8d248d956..1fe49724da9e 100644 --- a/include/linux/cpufreq.h +++ b/include/linux/cpufreq.h @@ -962,6 +962,7 @@ extern struct freq_attr cpufreq_freq_attr_scaling_boost_freqs; extern struct freq_attr *cpufreq_generic_attr[]; int cpufreq_table_validate_and_show(struct cpufreq_policy *policy, struct cpufreq_frequency_table *table); +int cpufreq_table_validate_and_sort(struct cpufreq_policy *policy); unsigned int cpufreq_generic_get(unsigned int cpu); int cpufreq_generic_init(struct cpufreq_policy *policy, -- cgit From 64bdff698092aa6be28c3b248f887022eec77902 Mon Sep 17 00:00:00 2001 From: "Rafael J. Wysocki" Date: Wed, 14 Mar 2018 12:27:21 +0100 Subject: PM: cpuidle/suspend: Add s2idle usage and time state attributes Add a new attribute group called "s2idle" under the sysfs directory of each cpuidle state that supports the ->enter_s2idle callback and put two new attributes, "usage" and "time", into that group to represent the number of times the given state was requested for suspend-to-idle and the total time spent in suspend-to-idle after requesting that state, respectively. That will allow diagnostic information related to suspend-to-idle to be collected without enabling advanced debug features and analyzing dmesg output. Signed-off-by: Rafael J. Wysocki --- include/linux/cpuidle.h | 4 ++++ 1 file changed, 4 insertions(+) (limited to 'include/linux') diff --git a/include/linux/cpuidle.h b/include/linux/cpuidle.h index 0b3fc229086c..a806e94c482f 100644 --- a/include/linux/cpuidle.h +++ b/include/linux/cpuidle.h @@ -33,6 +33,10 @@ struct cpuidle_state_usage { unsigned long long disable; unsigned long long usage; unsigned long long time; /* in US */ +#ifdef CONFIG_SUSPEND + unsigned long long s2idle_usage; + unsigned long long s2idle_time; /* in US */ +#endif }; struct cpuidle_state { -- cgit