timer: Add timer_curr_running()

This commit adds a timer_curr_running() function that verifies that the
current code is running in the context of the specified timer's handler.

Cc: Josh Triplett <josh@joshtriplett.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: Lai Jiangshan <jiangshanlai@gmail.com>
Cc: Joel Fernandes <joel@joelfernandes.org>
Cc: Neeraj Upadhyay <neeraju@codeaurora.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Tested-by: Boqun Feng <boqun.feng@gmail.com>
Signed-off-by: Frederic Weisbecker <frederic@kernel.org>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>

diff --git a/include/linux/timer.h b/include/linux/timer.h
index fda13c9..4118a97 100644 (file)
--- a/include/linux/timer.h
+++ b/include/linux/timer.h
@@ -192,6 +192,8 @@ extern int try_to_del_timer_sync(struct timer_list *timer);
 
 #define del_singleshot_timer_sync(t) del_timer_sync(t)
 
+extern bool timer_curr_running(struct timer_list *timer);
+
 extern void init_timers(void);
 struct hrtimer;
 extern enum hrtimer_restart it_real_fn(struct hrtimer *);

diff --git a/kernel/time/timer.c b/kernel/time/timer.c
index 8dbc008..f9b2096 100644 (file)
--- a/kernel/time/timer.c
+++ b/kernel/time/timer.c
@@ -1237,6 +1237,19 @@ int try_to_del_timer_sync(struct timer_list *timer)
 }
 EXPORT_SYMBOL(try_to_del_timer_sync);
 
+bool timer_curr_running(struct timer_list *timer)
+{
+       int i;
+
+       for (i = 0; i < NR_BASES; i++) {
+               struct timer_base *base = this_cpu_ptr(&timer_bases[i]);
+               if (base->running_timer == timer)
+                       return true;
+       }
+
+       return false;
+}
+
 #ifdef CONFIG_PREEMPT_RT
 static __init void timer_base_init_expiry_lock(struct timer_base *base)
 {