diff options
Diffstat (limited to 'kernel/cpu.c')
| -rw-r--r-- | kernel/cpu.c | 42 |
1 files changed, 16 insertions, 26 deletions
diff --git a/kernel/cpu.c b/kernel/cpu.c index 8df2d773fe3b..01968a5c4a16 100644 --- a/kernel/cpu.c +++ b/kernel/cpu.c @@ -534,6 +534,11 @@ int lockdep_is_cpus_held(void) { return percpu_rwsem_is_held(&cpu_hotplug_lock); } + +int lockdep_is_cpus_write_held(void) +{ + return percpu_rwsem_is_write_held(&cpu_hotplug_lock); +} #endif static void lockdep_acquire_cpus_lock(void) @@ -1410,6 +1415,16 @@ static int __ref _cpu_down(unsigned int cpu, int tasks_frozen, cpus_write_lock(); + /* + * Keep at least one housekeeping cpu onlined to avoid generating + * an empty sched_domain span. + */ + if (cpumask_any_and(cpu_online_mask, + housekeeping_cpumask(HK_TYPE_DOMAIN)) >= nr_cpu_ids) { + ret = -EBUSY; + goto out; + } + cpuhp_tasks_frozen = tasks_frozen; prev_state = cpuhp_set_state(cpu, st, target); @@ -1456,22 +1471,8 @@ out: return ret; } -struct cpu_down_work { - unsigned int cpu; - enum cpuhp_state target; -}; - -static long __cpu_down_maps_locked(void *arg) -{ - struct cpu_down_work *work = arg; - - return _cpu_down(work->cpu, 0, work->target); -} - static int cpu_down_maps_locked(unsigned int cpu, enum cpuhp_state target) { - struct cpu_down_work work = { .cpu = cpu, .target = target, }; - /* * If the platform does not support hotplug, report it explicitly to * differentiate it from a transient offlining failure. @@ -1480,18 +1481,7 @@ static int cpu_down_maps_locked(unsigned int cpu, enum cpuhp_state target) return -EOPNOTSUPP; if (cpu_hotplug_disabled) return -EBUSY; - - /* - * Ensure that the control task does not run on the to be offlined - * CPU to prevent a deadlock against cfs_b->period_timer. - * Also keep at least one housekeeping cpu onlined to avoid generating - * an empty sched_domain span. - */ - for_each_cpu_and(cpu, cpu_online_mask, housekeeping_cpumask(HK_TYPE_DOMAIN)) { - if (cpu != work.cpu) - return work_on_cpu(cpu, __cpu_down_maps_locked, &work); - } - return -EBUSY; + return _cpu_down(cpu, 0, target); } static int cpu_down(unsigned int cpu, enum cpuhp_state target) |