smpboot: Allow selfparking per cpu threads

The stop machine threads are still killed when a cpu goes offline. The
reason is that the thread is used to bring the cpu down, so it can't
be parked along with the other per cpu threads.

Allow a per cpu thread to be excluded from automatic parking, so it
can park itself once it's done

Add a create callback function as well.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Cc: Paul McKenney <paulmck@linux.vnet.ibm.com>
Cc: Srivatsa S. Bhat <srivatsa.bhat@linux.vnet.ibm.com>
Cc: Arjan van de Veen <arjan@infradead.org>
Cc: Paul Turner <pjt@google.com>
Cc: Richard Weinberger <rw@linutronix.de>
Cc: Magnus Damm <magnus.damm@gmail.com>
Link: http://lkml.kernel.org/r/20130131120741.553993267@linutronix.de
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

1 files changed, 5 insertions, 0 deletions

diff --git a/include/linux/smpboot.h b/include/linux/smpboot.h
index e0106d8581d3..c65dee059913 100644
--- a/include/linux/smpboot.h
+++ b/include/linux/smpboot.h
@@ -14,6 +14,8 @@ struct smpboot_thread_data;
  * @thread_should_run:  Check whether the thread should run or not. Called with
  *                      preemption disabled.
  * @thread_fn:          The associated thread function
+ * @create:             Optional setup function, called when the thread gets
+ *                      created (Not called from the thread context)
  * @setup:              Optional setup function, called when the thread gets
  *                      operational the first time
  * @cleanup:            Optional cleanup function, called when the thread
@@ -22,6 +24,7 @@ struct smpboot_thread_data;
  *                      parked (cpu offline)
  * @unpark:             Optional unpark function, called when the thread is
  *                      unparked (cpu online)
+ * @selfparking:        Thread is not parked by the park function.
  * @thread_comm:        The base name of the thread
  */
 struct smp_hotplug_thread {
@@ -29,10 +32,12 @@ struct smp_hotplug_thread {
         struct list_head                list;
         int                             (*thread_should_run)(unsigned int cpu);
         void                            (*thread_fn)(unsigned int cpu);
+        void                            (*create)(unsigned int cpu);
         void                            (*setup)(unsigned int cpu);
         void                            (*cleanup)(unsigned int cpu, bool online);
         void                            (*park)(unsigned int cpu);
         void                            (*unpark)(unsigned int cpu);
+        bool                            selfparking;
         const char                      *thread_comm;
 };