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>

1 files changed, 4 insertions, 4 deletions

diff --git a/kernel/timer.c b/kernel/timer.c
index 4296d13db3d1..6582b82fa966 100644
--- a/kernel/timer.c
+++ b/kernel/timer.c
@@ -1092,7 +1092,7 @@ static int cascade(struct tvec_base *base, struct tvec *tv, int index)
 static void call_timer_fn(struct timer_list *timer, void (*fn)(unsigned long),
                           unsigned long data)
 {
-        int preempt_count = preempt_count();
+        int count = preempt_count();
 
 #ifdef CONFIG_LOCKDEP
         /*
@@ -1119,16 +1119,16 @@ static void call_timer_fn(struct timer_list *timer, void (*fn)(unsigned long),
 
         lock_map_release(&lockdep_map);
 
-        if (preempt_count != preempt_count()) {
+        if (count != preempt_count()) {
                 WARN_ONCE(1, "timer: %pF preempt leak: %08x -> %08x\n",
-                          fn, preempt_count, preempt_count());
+                          fn, count, preempt_count());
                 /*
                  * Restore the preempt count. That gives us a decent
                  * chance to survive and extract information. If the
                  * callback kept a lock held, bad luck, but not worse
                  * than the BUG() we had.
                  */
-                preempt_count() = preempt_count;
+                preempt_count_set(count);
         }
 }