From: David Woodhouse <dwmw@xxxxxxxxxxxx>
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@xxxxxxxxxxxx>
Reviewed-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Signed-off-by: Usama Arif <usama.arif@xxxxxxxxxxxxx>
Tested-by: Paul E. McKenney <paulmck@xxxxxxxxxx>
Tested-by: Kim Phillips <kim.phillips@xxxxxxx>
Tested-by: Oleksandr Natalenko <oleksandr@xxxxxxxxxxxxxx>
Tested-by: Guilherme G. Piccoli <gpiccoli@xxxxxxxxxx>
Reviewed-by: Mark Rutland <mark.rutland@xxxxxxx>
Tested-by: Mark Rutland <mark.rutland@xxxxxxx> [arm64]
---
include/linux/smpboot.h | 7 +++++++
kernel/smpboot.h | 2 --
2 files changed, 7 insertions(+), 2 deletions(-)
diff --git a/include/linux/smpboot.h b/include/linux/smpboot.h
index 9d1bc65d226c..3862addcaa34 100644
--- 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 34dd3d7ba40b..60c609318ad6 100644
--- 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
--
2.25.1
