sched: Extract the basic add/sub preempt_count modifiers

Rewrite the preempt_count macros in order to extract the 3 basic
preempt_count value modifiers:

  __preempt_count_add()
  __preempt_count_sub()

and the new:

  __preempt_count_dec_and_test()

And since we're at it anyway, replace the unconventional
$op_preempt_count names with the more conventional preempt_count_$op.

Since these basic operators are equivalent to the previous _notrace()
variants, do away with the _notrace() versions.

Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/n/tip-ewbpdbupy9xpsjhg960zwbv8@git.kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>

1 files changed, 35 insertions, 0 deletions

diff --git a/include/asm-generic/preempt.h b/include/asm-generic/preempt.h
index 8100b1ec1715..82d958fc3823 100644
--- a/include/asm-generic/preempt.h
+++ b/include/asm-generic/preempt.h
@@ -65,4 +65,39 @@ static __always_inline bool test_preempt_need_resched(void)
         return !(*preempt_count_ptr() & PREEMPT_NEED_RESCHED);
 }
 
+/*
+ * The various preempt_count add/sub methods
+ */
+
+static __always_inline void __preempt_count_add(int val)
+{
+        *preempt_count_ptr() += val;
+}
+
+static __always_inline void __preempt_count_sub(int val)
+{
+        *preempt_count_ptr() -= val;
+}
+
+static __always_inline bool __preempt_count_dec_and_test(void)
+{
+        return !--*preempt_count_ptr();
+}
+
+/*
+ * Returns true when we need to resched -- even if we can not.
+ */
+static __always_inline bool need_resched(void)
+{
+        return unlikely(test_preempt_need_resched());
+}
+
+/*
+ * Returns true when we need to resched and can (barring IRQ state).
+ */
+static __always_inline bool should_resched(void)
+{
+        return unlikely(!*preempt_count_ptr());
+}
+
 #endif /* __ASM_PREEMPT_H */