diff options
| -rw-r--r-- | include/linux/cpuhplock.h | 2 | ||||
| -rw-r--r-- | kernel/cpu.c | 13 |
2 files changed, 14 insertions, 1 deletions
diff --git a/include/linux/cpuhplock.h b/include/linux/cpuhplock.h index 431560bbd045..f7aa20f62b87 100644 --- a/include/linux/cpuhplock.h +++ b/include/linux/cpuhplock.h @@ -21,6 +21,7 @@ void cpus_read_lock(void); void cpus_read_unlock(void); int cpus_read_trylock(void); void lockdep_assert_cpus_held(void); +void cpu_hotplug_disable_offlining(void); void cpu_hotplug_disable(void); void cpu_hotplug_enable(void); void clear_tasks_mm_cpumask(int cpu); @@ -36,6 +37,7 @@ static inline void cpus_read_lock(void) { } static inline void cpus_read_unlock(void) { } static inline int cpus_read_trylock(void) { return true; } static inline void lockdep_assert_cpus_held(void) { } +static inline void cpu_hotplug_disable_offlining(void) { } static inline void cpu_hotplug_disable(void) { } static inline void cpu_hotplug_enable(void) { } static inline int remove_cpu(unsigned int cpu) { return -EPERM; } diff --git a/kernel/cpu.c b/kernel/cpu.c index 563877d6c28b..4c15b478e2bc 100644 --- a/kernel/cpu.c +++ b/kernel/cpu.c @@ -483,6 +483,8 @@ static int cpu_hotplug_disabled; DEFINE_STATIC_PERCPU_RWSEM(cpu_hotplug_lock); +static bool cpu_hotplug_offline_disabled __ro_after_init; + void cpus_read_lock(void) { percpu_down_read(&cpu_hotplug_lock); @@ -542,6 +544,14 @@ static void lockdep_release_cpus_lock(void) rwsem_release(&cpu_hotplug_lock.dep_map, _THIS_IP_); } +/* Declare CPU offlining not supported */ +void cpu_hotplug_disable_offlining(void) +{ + cpu_maps_update_begin(); + cpu_hotplug_offline_disabled = true; + cpu_maps_update_done(); +} + /* * Wait for currently running CPU hotplug operations to complete (if any) and * disable future CPU hotplug (from sysfs). The 'cpu_add_remove_lock' protects @@ -1471,7 +1481,8 @@ static int cpu_down_maps_locked(unsigned int cpu, enum cpuhp_state target) * If the platform does not support hotplug, report it explicitly to * differentiate it from a transient offlining failure. */ - if (cc_platform_has(CC_ATTR_HOTPLUG_DISABLED)) + if (cc_platform_has(CC_ATTR_HOTPLUG_DISABLED) || + cpu_hotplug_offline_disabled) return -EOPNOTSUPP; if (cpu_hotplug_disabled) return -EBUSY; |