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| author | Thomas Gleixner <tglx@linutronix.de> | 2022-11-23 21:18:53 +0100 |
|---|---|---|
| committer | Thomas Gleixner <tglx@linutronix.de> | 2022-11-24 15:09:12 +0100 |
| commit | f571faf6e443b6011ccb585d57866177af1f643c (patch) | |
| tree | 8d74854eea3753a7888f939a8256e9c73279488b /include/linux/timer.h | |
| parent | 0cc04e80458a822300b93f82ed861a513edde194 (diff) | |
| download | linux-f571faf6e443b6011ccb585d57866177af1f643c.tar.bz2 | |
timers: Provide timer_shutdown[_sync]()
Tearing down timers which have circular dependencies to other
functionality, e.g. workqueues, where the timer can schedule work and work
can arm timers, is not trivial.
In those cases it is desired to shutdown the timer in a way which prevents
rearming of the timer. The mechanism to do so is to set timer->function to
NULL and use this as an indicator for the timer arming functions to ignore
the (re)arm request.
Expose new interfaces for this: timer_shutdown_sync() and timer_shutdown().
timer_shutdown_sync() has the same functionality as timer_delete_sync()
plus the NULL-ification of the timer function.
timer_shutdown() has the same functionality as timer_delete() plus the
NULL-ification of the timer function.
In both cases the rearming of the timer is prevented by silently discarding
rearm attempts due to timer->function being NULL.
Co-developed-by: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Tested-by: Guenter Roeck <linux@roeck-us.net>
Reviewed-by: Jacob Keller <jacob.e.keller@intel.com>
Reviewed-by: Anna-Maria Behnsen <anna-maria@linutronix.de>
Link: https://lore.kernel.org/all/20220407161745.7d6754b3@gandalf.local.home
Link: https://lore.kernel.org/all/20221110064101.429013735@goodmis.org
Link: https://lore.kernel.org/r/20221123201625.314230270@linutronix.de
Diffstat (limited to 'include/linux/timer.h')
| -rw-r--r-- | include/linux/timer.h | 2 |
1 files changed, 2 insertions, 0 deletions
diff --git a/include/linux/timer.h b/include/linux/timer.h index e338e173ce8b..9162f275819a 100644 --- a/include/linux/timer.h +++ b/include/linux/timer.h @@ -184,6 +184,8 @@ extern void add_timer(struct timer_list *timer); extern int try_to_del_timer_sync(struct timer_list *timer); extern int timer_delete_sync(struct timer_list *timer); extern int timer_delete(struct timer_list *timer); +extern int timer_shutdown_sync(struct timer_list *timer); +extern int timer_shutdown(struct timer_list *timer); /** * del_timer_sync - Delete a pending timer and wait for a running callback |