cpu/hotplug: Handle early registration gracefully
authorThomas Gleixner <tglx@linutronix.de>
Wed, 13 Jul 2016 17:16:03 +0000 (17:16 +0000)
committerIngo Molnar <mingo@kernel.org>
Thu, 14 Jul 2016 07:34:25 +0000 (09:34 +0200)
We switched the hotplug machinery to smpboot threads. Early registration of
hotplug callbacks, i.e. from do_pre_smp_initcalls(), happens before the
threads are initialized. Instead of moving the thread init, we simply handle
it in the hotplug code itself and invoke the function directly.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Anna-Maria Gleixner <anna-maria@linutronix.de>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: rt@linutronix.de
Link: http://lkml.kernel.org/r/20160713153332.896450738@linutronix.de
Signed-off-by: Ingo Molnar <mingo@kernel.org>
kernel/cpu.c

index 7b61887f7ccdf57fdcb3083574a56c5580110d73..fe71ce4e60f138c161f0e5c1bba5e17842081b0e 100644 (file)
@@ -517,6 +517,13 @@ static int cpuhp_invoke_ap_callback(int cpu, enum cpuhp_state state,
        if (!cpu_online(cpu))
                return 0;
 
+       /*
+        * If we are up and running, use the hotplug thread. For early calls
+        * we invoke the thread function directly.
+        */
+       if (!st->thread)
+               return cpuhp_invoke_callback(cpu, state, cb);
+
        st->cb_state = state;
        st->cb = cb;
        /*