From a31323bef2b66455920d054b160c17d4240f8fd4 Mon Sep 17 00:00:00 2001 From: "Steven Rostedt (Google)" Date: Wed, 23 Nov 2022 21:18:55 +0100 Subject: timers: Update the documentation to reflect on the new timer_shutdown() API In order to make sure that a timer is not re-armed after it is stopped before freeing, a new shutdown state is added to the timer code. The API timer_shutdown_sync() and timer_shutdown() must be called before the object that holds the timer can be freed. Update the documentation to reflect this new workflow. [ tglx: Updated to the new semantics and updated the zh_CN version ] Signed-off-by: Steven Rostedt (Google) Signed-off-by: Thomas Gleixner Tested-by: Guenter Roeck Reviewed-by: Jacob Keller Reviewed-by: Anna-Maria Behnsen Link: https://lore.kernel.org/r/20221110064147.712934793@goodmis.org Link: https://lore.kernel.org/r/20221123201625.375284489@linutronix.de --- Documentation/kernel-hacking/locking.rst | 5 +++++ 1 file changed, 5 insertions(+) (limited to 'Documentation/kernel-hacking') diff --git a/Documentation/kernel-hacking/locking.rst b/Documentation/kernel-hacking/locking.rst index c5b8678ed232..c756786e17ae 100644 --- a/Documentation/kernel-hacking/locking.rst +++ b/Documentation/kernel-hacking/locking.rst @@ -1007,6 +1007,11 @@ calling add_timer() at the end of their timer function). Because this is a fairly common case which is prone to races, you should use timer_delete_sync() (``include/linux/timer.h``) to handle this case. +Before freeing a timer, timer_shutdown() or timer_shutdown_sync() should be +called which will keep it from being rearmed. Any subsequent attempt to +rearm the timer will be silently ignored by the core code. + + Locking Speed ============= -- cgit v1.2.3