cpu/hotplug: Move idle_thread_get() to <linux/smpboot.h>

Instead of relying purely on the special-case wrapper in bringup_cpu()
to pass the idle thread to __cpu_up(), expose idle_thread_get() so that
the architecture code can obtain it directly when necessary.

This will be useful when the existing __cpu_up() is split into multiple
phases, only *one* of which will actually need the idle thread.

If the architecture code is to register its new pre-bringup states with
the cpuhp core, having a special-case wrapper to pass extra arguments is
non-trivial and it's easier just to let the arch register its function
pointer to be invoked with the standard API.

Signed-off-by: David Woodhouse <dwmw@amazon.co.uk>

diff --git a/include/linux/smpboot.h b/include/linux/smpboot.h
index 9d1bc65d226cc00b8cbd73484279ed3d6aa852d9..3862addcaa34923e24267a16e53a1c63e8274480 100644 (file)
--- a/include/linux/smpboot.h
+++ b/include/linux/smpboot.h
@@ -5,6 +5,13 @@
 #include <linux/types.h>
 
 struct task_struct;
+
+#ifdef CONFIG_GENERIC_SMP_IDLE_THREAD
+struct task_struct *idle_thread_get(unsigned int cpu);
+#else
+static inline struct task_struct *idle_thread_get(unsigned int cpu) { return NULL; }
+#endif
+
 /* Cookie handed to the thread_fn*/
 struct smpboot_thread_data;
 

diff --git a/kernel/smpboot.h b/kernel/smpboot.h
index 34dd3d7ba40bc0a5e3a11d7cf5cea4a641f030ad..60c609318ad6d208136a77ca99a797b442e0dc35 100644 (file)
--- a/kernel/smpboot.h
+++ b/kernel/smpboot.h
@@ -5,11 +5,9 @@
 struct task_struct;
 
 #ifdef CONFIG_GENERIC_SMP_IDLE_THREAD
-struct task_struct *idle_thread_get(unsigned int cpu);
 void idle_thread_set_boot_cpu(void);
 void idle_threads_init(void);
 #else
-static inline struct task_struct *idle_thread_get(unsigned int cpu) { return NULL; }
 static inline void idle_thread_set_boot_cpu(void) { }
 static inline void idle_threads_init(void) { }
 #endif