[PATCH 03/11] timers: Rename del_timer_sync() to timer_delete_sync()

[Yuxuan Luo]

From: Thomas Gleixner <tglx at linutronix.de>

The timer related functions do not have a strict timer_ prefixed namespace
which is really annoying.

Rename del_timer_sync() to timer_delete_sync() and provide del_timer_sync()
as a wrapper. Document that del_timer_sync() is not for new code.

Signed-off-by: Thomas Gleixner <tglx at linutronix.de>
Tested-by: Guenter Roeck <linux at roeck-us.net>
Reviewed-by: Steven Rostedt (Google) <rostedt at goodmis.org>
Reviewed-by: Jacob Keller <jacob.e.keller at intel.com>
Reviewed-by: Anna-Maria Behnsen <anna-maria at linutronix.de>
Link: https://lore.kernel.org/r/20221123201624.954785441@linutronix.de

(cherry picked from commit 9b13df3fb64ee95e2397585404e442afee2c7d4f)
CVE-2023-6039
Signed-off-by: Yuxuan Luo <yuxuan.luo at canonical.com>
---
 include/linux/timer.h | 15 ++++++++++++++-
 kernel/time/timer.c   | 18 +++++++++---------
 2 files changed, 23 insertions(+), 10 deletions(-)

diff --git a/include/linux/timer.h b/include/linux/timer.h
index 2e6f50b342662..e78521bce565a 100644
--- a/include/linux/timer.h
+++ b/include/linux/timer.h
@@ -183,7 +183,20 @@ extern int timer_reduce(struct timer_list *timer, unsigned long expires);
 extern void add_timer(struct timer_list *timer);
 
 extern int try_to_del_timer_sync(struct timer_list *timer);
-extern int del_timer_sync(struct timer_list *timer);
+extern int timer_delete_sync(struct timer_list *timer);
+
+/**
+ * del_timer_sync - Delete a pending timer and wait for a running callback
+ * @timer:	The timer to be deleted
+ *
+ * See timer_delete_sync() for detailed explanation.
+ *
+ * Do not use in new code. Use timer_delete_sync() instead.
+ */
+static inline int del_timer_sync(struct timer_list *timer)
+{
+	return timer_delete_sync(timer);
+}
 
 #define del_singleshot_timer_sync(t) del_timer_sync(t)
 
diff --git a/kernel/time/timer.c b/kernel/time/timer.c
index 2c0e26718c7a9..d4ce3ebe2c8cf 100644
--- a/kernel/time/timer.c
+++ b/kernel/time/timer.c
@@ -1030,7 +1030,7 @@ __mod_timer(struct timer_list *timer, unsigned long expires, unsigned int option
 		/*
 		 * We are trying to schedule the timer on the new base.
 		 * However we can't change timer's base while it is running,
-		 * otherwise del_timer_sync() can't detect that the timer's
+		 * otherwise timer_delete_sync() can't detect that the timer's
 		 * handler yet has not finished. This also guarantees that the
 		 * timer is serialized wrt itself.
 		 */
@@ -1206,7 +1206,7 @@ EXPORT_SYMBOL_GPL(add_timer_on);
  * @timer:	The timer to be deactivated
  *
  * The function only deactivates a pending timer, but contrary to
- * del_timer_sync() it does not take into account whether the timer's
+ * timer_delete_sync() it does not take into account whether the timer's
  * callback function is concurrently executed on a different CPU or not.
  * It neither prevents rearming of the timer. If @timer can be rearmed
  * concurrently then the return value of this function is meaningless.
@@ -1342,7 +1342,7 @@ static inline void del_timer_wait_running(struct timer_list *timer) { }
 #endif
 
 /**
- * del_timer_sync - Deactivate a timer and wait for the handler to finish.
+ * timer_delete_sync - Deactivate a timer and wait for the handler to finish.
  * @timer:	The timer to be deactivated
  *
  * Synchronization rules: Callers must prevent restarting of the timer,
@@ -1364,10 +1364,10 @@ static inline void del_timer_wait_running(struct timer_list *timer) { }
  *    spin_lock_irq(somelock);
  *                                     <IRQ>
  *                                        spin_lock(somelock);
- *    del_timer_sync(mytimer);
+ *    timer_delete_sync(mytimer);
  *    while (base->running_timer == mytimer);
  *
- * Now del_timer_sync() will never return and never release somelock.
+ * Now timer_delete_sync() will never return and never release somelock.
  * The interrupt on the other CPU is waiting to grab somelock but it has
  * interrupted the softirq that CPU0 is waiting to finish.
  *
@@ -1380,7 +1380,7 @@ static inline void del_timer_wait_running(struct timer_list *timer) { }
  * * %0	- The timer was not pending
  * * %1	- The timer was pending and deactivated
  */
-int del_timer_sync(struct timer_list *timer)
+int timer_delete_sync(struct timer_list *timer)
 {
 	int ret;
 
@@ -1420,7 +1420,7 @@ int del_timer_sync(struct timer_list *timer)
 
 	return ret;
 }
-EXPORT_SYMBOL(del_timer_sync);
+EXPORT_SYMBOL(timer_delete_sync);
 
 static void call_timer_fn(struct timer_list *timer,
 			  void (*fn)(struct timer_list *),
@@ -1442,8 +1442,8 @@ static void call_timer_fn(struct timer_list *timer,
 #endif
 	/*
 	 * Couple the lock chain with the lock chain at
-	 * del_timer_sync() by acquiring the lock_map around the fn()
-	 * call here and in del_timer_sync().
+	 * timer_delete_sync() by acquiring the lock_map around the fn()
+	 * call here and in timer_delete_sync().
 	 */
 	lock_map_acquire(&lockdep_map);
 
-- 
2.34.1