Merge remote-tracking branch 'asoc/topic/simple' into asoc-next

[cascardo/linux.git] / kernel / cpu.c

diff --git a/kernel/cpu.c b/kernel/cpu.c
index 6ea42e8..3e3f6e4 100644 (file)
--- a/kernel/cpu.c
+++ b/kernel/cpu.c
@@ -36,6 +36,7 @@
  * @target:    The target state
  * @thread:    Pointer to the hotplug thread
  * @should_run:        Thread should execute
+ * @rollback:  Perform a rollback
  * @cb_stat:   The state for a single callback (install/uninstall)
  * @cb:                Single callback function (install/uninstall)
  * @result:    Result of the operation
@@ -47,6 +48,7 @@ struct cpuhp_cpu_state {
 #ifdef CONFIG_SMP
        struct task_struct      *thread;
        bool                    should_run;
+       bool                    rollback;
        enum cpuhp_state        cb_state;
        int                     (*cb)(unsigned int cpu);
        int                     result;
@@ -301,6 +303,11 @@ static int cpu_notify(unsigned long val, unsigned int cpu)
        return __cpu_notify(val, cpu, -1, NULL);
 }
 
+static void cpu_notify_nofail(unsigned long val, unsigned int cpu)
+{
+       BUG_ON(cpu_notify(val, cpu));
+}
+
 /* Notifier wrappers for transitioning to state machine */
 static int notify_prepare(unsigned int cpu)
 {
@@ -477,6 +484,16 @@ static void cpuhp_thread_fun(unsigned int cpu)
                } else {
                        ret = cpuhp_invoke_callback(cpu, st->cb_state, st->cb);
                }
+       } else if (st->rollback) {
+               BUG_ON(st->state < CPUHP_AP_ONLINE_IDLE);
+
+               undo_cpu_down(cpu, st, cpuhp_ap_states);
+               /*
+                * This is a momentary workaround to keep the notifier users
+                * happy. Will go away once we got rid of the notifiers.
+                */
+               cpu_notify_nofail(CPU_DOWN_FAILED, cpu);
+               st->rollback = false;
        } else {
                /* Cannot happen .... */
                BUG_ON(st->state < CPUHP_AP_ONLINE_IDLE);
@@ -636,11 +653,6 @@ static inline void check_for_tasks(int dead_cpu)
        read_unlock(&tasklist_lock);
 }
 
-static void cpu_notify_nofail(unsigned long val, unsigned int cpu)
-{
-       BUG_ON(cpu_notify(val, cpu));
-}
-
 static int notify_down_prepare(unsigned int cpu)
 {
        int err, nr_calls = 0;
@@ -721,9 +733,10 @@ static int takedown_cpu(unsigned int cpu)
         */
        err = stop_machine(take_cpu_down, NULL, cpumask_of(cpu));
        if (err) {
-               /* CPU didn't die: tell everyone.  Can't complain. */
-               cpu_notify_nofail(CPU_DOWN_FAILED, cpu);
+               /* CPU refused to die */
                irq_unlock_sparse();
+               /* Unpark the hotplug thread so we can rollback there */
+               kthread_unpark(per_cpu_ptr(&cpuhp_state, cpu)->thread);
                return err;
        }
        BUG_ON(cpu_online(cpu));
@@ -832,6 +845,11 @@ static int __ref _cpu_down(unsigned int cpu, int tasks_frozen,
         * to do the further cleanups.
         */
        ret = cpuhp_down_callbacks(cpu, st, cpuhp_bp_states, target);
+       if (ret && st->state > CPUHP_TEARDOWN_CPU && st->state < prev_state) {
+               st->target = prev_state;
+               st->rollback = true;
+               cpuhp_kick_ap_work(cpu);
+       }
 
        hasdied = prev_state != st->state && st->state == CPUHP_OFFLINE;
 out:
@@ -1249,6 +1267,7 @@ static struct cpuhp_step cpuhp_ap_states[] = {
                .name                   = "notify:online",
                .startup                = notify_online,
                .teardown               = notify_down_prepare,
+               .skip_onerr             = true,
        },
 #endif
        /*