sched: Introduce preempt_count accessor functions

Replace the single preempt_count() 'function' that's an lvalue with
two proper functions:

 preempt_count() - returns the preempt_count value as rvalue
 preempt_count_set() - Allows setting the preempt-count value

Also provide preempt_count_ptr() as a convenience wrapper to implement
all modifying operations.

Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/n/tip-orxrbycjozopqfhb4dxdkdvb@git.kernel.org
[ Fixed build failure. ]
Signed-off-by: Ingo Molnar <mingo@kernel.org>

2 files changed, 2 insertions, 3 deletions

diff --git a/lib/locking-selftest.c b/lib/locking-selftest.c
index 6dc09d8f4c24..872a15a2a637 100644
--- a/lib/locking-selftest.c
+++ b/lib/locking-selftest.c
@@ -1002,7 +1002,7 @@ static void dotest(void (*testcase_fn)(void), int expected, int lockclass_mask)
          * Some tests (e.g. double-unlock) might corrupt the preemption
          * count, so restore it:
          */
-        preempt_count() = saved_preempt_count;
+        preempt_count_set(saved_preempt_count);
 #ifdef CONFIG_TRACE_IRQFLAGS
         if (softirq_count())
                 current->softirqs_enabled = 0;
diff --git a/lib/smp_processor_id.c b/lib/smp_processor_id.c
index 4c0d0e51d49e..04abe53f12a1 100644
--- a/lib/smp_processor_id.c
+++ b/lib/smp_processor_id.c
@@ -9,10 +9,9 @@
 
 notrace unsigned int debug_smp_processor_id(void)
 {
-        unsigned long preempt_count = preempt_count();
         int this_cpu = raw_smp_processor_id();
 
-        if (likely(preempt_count))
+        if (likely(preempt_count()))
                 goto out;
 
         if (irqs_disabled())