From dcd42591ebb8a25895b551a5297ea9c24414ba54 Mon Sep 17 00:00:00 2001
From: Frederic Weisbecker <frederic@kernel.org>
Date: Fri, 13 Nov 2020 13:13:33 +0100
Subject: [PATCH] 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>
---
include/linux/timer.h | 2 ++
kernel/time/timer.c | 13 +++++++++++++
2 files changed, 15 insertions(+)
diff --git a/include/linux/timer.h b/include/linux/timer.h
index fda13c9d1256c..4118a97e62fb4 100644
--- 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 8dbc008f8942b..f9b2096456e59 100644
--- 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)
{