sched: Isolate preempt counting in its own config option

Create a new CONFIG_PREEMPT_COUNT that handles the inc/dec
of preempt count offset independently. So that the offset
can be updated by preempt_disable() and preempt_enable()
even without the need for CONFIG_PREEMPT beeing set.

This prepares to make CONFIG_DEBUG_SPINLOCK_SLEEP working
with !CONFIG_PREEMPT where it currently doesn't detect
code that sleeps inside explicit preemption disabled
sections.

Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Acked-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>

1 files changed, 17 insertions, 9 deletions

diff --git a/include/linux/preempt.h b/include/linux/preempt.h
index 2e681d9555bd..58969b2a8a82 100644
--- a/include/linux/preempt.h
+++ b/include/linux/preempt.h
@@ -27,6 +27,21 @@
 
 asmlinkage void preempt_schedule(void);
 
+#define preempt_check_resched() \
+do { \
+        if (unlikely(test_thread_flag(TIF_NEED_RESCHED))) \
+                preempt_schedule(); \
+} while (0)
+
+#else /* !CONFIG_PREEMPT */
+
+#define preempt_check_resched()         do { } while (0)
+
+#endif /* CONFIG_PREEMPT */
+
+
+#ifdef CONFIG_PREEMPT_COUNT
+
 #define preempt_disable() \
 do { \
         inc_preempt_count(); \
@@ -39,12 +54,6 @@ do { \
         dec_preempt_count(); \
 } while (0)
 
-#define preempt_check_resched() \
-do { \
-        if (unlikely(test_thread_flag(TIF_NEED_RESCHED))) \
-                preempt_schedule(); \
-} while (0)
-
 #define preempt_enable() \
 do { \
         preempt_enable_no_resched(); \
@@ -80,18 +89,17 @@ do { \
         preempt_check_resched(); \
 } while (0)
 
-#else
+#else /* !CONFIG_PREEMPT_COUNT */
 
 #define preempt_disable()               do { } while (0)
 #define preempt_enable_no_resched()     do { } while (0)
 #define preempt_enable()                do { } while (0)
-#define preempt_check_resched()         do { } while (0)
 
 #define preempt_disable_notrace()               do { } while (0)
 #define preempt_enable_no_resched_notrace()     do { } while (0)
 #define preempt_enable_notrace()                do { } while (0)
 
-#endif
+#endif /* CONFIG_PREEMPT_COUNT */
 
 #ifdef CONFIG_PREEMPT_NOTIFIERS