locking/rtmutex: Restrict the trylock WARN_ON() to debug

The warning as written is expensive and not really required for a
production kernel. Make it depend on rt mutex debugging and use !in_task()
for the condition which generates far better code and gives the same
answer.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lore.kernel.org/r/20210326153944.436565064@linutronix.de

diff --git a/kernel/locking/rtmutex.c b/kernel/locking/rtmutex.c
index 512b400..c68542d 100644 (file)
--- a/kernel/locking/rtmutex.c
+++ b/kernel/locking/rtmutex.c
@@ -1456,7 +1456,7 @@ int __sched rt_mutex_trylock(struct rt_mutex *lock)
 {
        int ret;
 
-       if (WARN_ON_ONCE(in_irq() || in_nmi() || in_serving_softirq()))
+       if (IS_ENABLED(CONFIG_DEBUG_RT_MUTEXES) && WARN_ON_ONCE(!in_task()))
                return 0;
 
        /*