From: Benjamin Berg benjamin.berg@intel.com

The normal timer mechanism assume that timeout further in the future need a lower accuracy. As an example, the granularity for a timer scheduled 4096 ms in the future on a 1000 Hz system is already 512 ms. This granularity is perfectly sufficient for e.g. timeouts, but there are other types of events that will happen at a future point in time and require a higher accuracy.

Add a new wiphy_hrtimer_work type that uses an hrtimer internally. The API is almost identical to the existing wiphy_delayed_work and it can be used as a drop-in replacement after minor adjustments. The work will be scheduled relative to the current time with a slack of 1 millisecond.

CC: stable@vger.kernel.org # 6.4+ Signed-off-by: Benjamin Berg benjamin.berg@intel.com Reviewed-by: Johannes Berg johannes.berg@intel.com Signed-off-by: Miri Korenblit miriam.rachel.korenblit@intel.com Link: https://patch.msgid.link/20251028125710.7f13a2adc5eb.I01b5af0363869864b0580d... Signed-off-by: Johannes Berg johannes.berg@intel.com --- include/net/cfg80211.h | 78 ++++++++++++++++++++++++++++++++++++++++++ net/wireless/core.c | 56 ++++++++++++++++++++++++++++++ net/wireless/trace.h | 21 ++++++++++++ 3 files changed, 155 insertions(+)

diff --git a/include/net/cfg80211.h b/include/net/cfg80211.h index c555d9964702c..96121dc14e826 100644 --- a/include/net/cfg80211.h +++ b/include/net/cfg80211.h @@ -6105,6 +6105,11 @@ static inline void wiphy_delayed_work_init(struct wiphy_delayed_work *dwork, * after wiphy_lock() was called. Therefore, wiphy_cancel_work() can * use just cancel_work() instead of cancel_work_sync(), it requires * being in a section protected by wiphy_lock(). + * + * Note that these are scheduled with a timer where the accuracy + * becomes less the longer in the future the scheduled timer is. Use + * wiphy_hrtimer_work_queue() if the timer must be not be late by more + * than approximately 10 percent. */ void wiphy_delayed_work_queue(struct wiphy *wiphy, struct wiphy_delayed_work *dwork, @@ -6176,6 +6181,79 @@ void wiphy_delayed_work_flush(struct wiphy *wiphy, bool wiphy_delayed_work_pending(struct wiphy *wiphy, struct wiphy_delayed_work *dwork);

+struct wiphy_hrtimer_work { + struct wiphy_work work; + struct wiphy *wiphy; + struct hrtimer timer; +}; + +enum hrtimer_restart wiphy_hrtimer_work_timer(struct hrtimer *t); + +static inline void wiphy_hrtimer_work_init(struct wiphy_hrtimer_work *hrwork, + wiphy_work_func_t func) +{ + hrtimer_init(&hrwork->timer, CLOCK_BOOTTIME, HRTIMER_MODE_REL); + hrwork->timer.function = wiphy_hrtimer_work_timer; + wiphy_work_init(&hrwork->work, func); +} + +/** + * wiphy_hrtimer_work_queue - queue hrtimer work for the wiphy + * @wiphy: the wiphy to queue for + * @hrwork: the high resolution timer worker + * @delay: the delay given as a ktime_t + * + * Please refer to wiphy_delayed_work_queue(). The difference is that + * the hrtimer work uses a high resolution timer for scheduling. This + * may be needed if timeouts might be scheduled further in the future + * and the accuracy of the normal timer is not sufficient. + * + * Expect a delay of a few milliseconds as the timer is scheduled + * with some slack and some more time may pass between queueing the + * work and its start. + */ +void wiphy_hrtimer_work_queue(struct wiphy *wiphy, + struct wiphy_hrtimer_work *hrwork, + ktime_t delay); + +/** + * wiphy_hrtimer_work_cancel - cancel previously queued hrtimer work + * @wiphy: the wiphy, for debug purposes + * @hrtimer: the hrtimer work to cancel + * + * Cancel the work *without* waiting for it, this assumes being + * called under the wiphy mutex acquired by wiphy_lock(). + */ +void wiphy_hrtimer_work_cancel(struct wiphy *wiphy, + struct wiphy_hrtimer_work *hrtimer); + +/** + * wiphy_hrtimer_work_flush - flush previously queued hrtimer work + * @wiphy: the wiphy, for debug purposes + * @hrwork: the hrtimer work to flush + * + * Flush the work (i.e. run it if pending). This must be called + * under the wiphy mutex acquired by wiphy_lock(). + */ +void wiphy_hrtimer_work_flush(struct wiphy *wiphy, + struct wiphy_hrtimer_work *hrwork); + +/** + * wiphy_hrtimer_work_pending - Find out whether a wiphy hrtimer + * work item is currently pending. + * + * @wiphy: the wiphy, for debug purposes + * @hrwork: the hrtimer work in question + * + * Return: true if timer is pending, false otherwise + * + * Please refer to the wiphy_delayed_work_pending() documentation as + * this is the equivalent function for hrtimer based delayed work + * items. + */ +bool wiphy_hrtimer_work_pending(struct wiphy *wiphy, + struct wiphy_hrtimer_work *hrwork); + /** * enum ieee80211_ap_reg_power - regulatory power for an Access Point * diff --git a/net/wireless/core.c b/net/wireless/core.c index 586e50678ed80..dc207a8986c7f 100644 --- a/net/wireless/core.c +++ b/net/wireless/core.c @@ -1763,6 +1763,62 @@ bool wiphy_delayed_work_pending(struct wiphy *wiphy, } EXPORT_SYMBOL_GPL(wiphy_delayed_work_pending);

+enum hrtimer_restart wiphy_hrtimer_work_timer(struct hrtimer *t) +{ + struct wiphy_hrtimer_work *hrwork = + container_of(t, struct wiphy_hrtimer_work, timer); + + wiphy_work_queue(hrwork->wiphy, &hrwork->work); + + return HRTIMER_NORESTART; +} +EXPORT_SYMBOL_GPL(wiphy_hrtimer_work_timer); + +void wiphy_hrtimer_work_queue(struct wiphy *wiphy, + struct wiphy_hrtimer_work *hrwork, + ktime_t delay) +{ + trace_wiphy_hrtimer_work_queue(wiphy, &hrwork->work, delay); + + if (!delay) { + hrtimer_cancel(&hrwork->timer); + wiphy_work_queue(wiphy, &hrwork->work); + return; + } + + hrwork->wiphy = wiphy; + hrtimer_start_range_ns(&hrwork->timer, delay, + 1000 * NSEC_PER_USEC, HRTIMER_MODE_REL); +} +EXPORT_SYMBOL_GPL(wiphy_hrtimer_work_queue); + +void wiphy_hrtimer_work_cancel(struct wiphy *wiphy, + struct wiphy_hrtimer_work *hrwork) +{ + lockdep_assert_held(&wiphy->mtx); + + hrtimer_cancel(&hrwork->timer); + wiphy_work_cancel(wiphy, &hrwork->work); +} +EXPORT_SYMBOL_GPL(wiphy_hrtimer_work_cancel); + +void wiphy_hrtimer_work_flush(struct wiphy *wiphy, + struct wiphy_hrtimer_work *hrwork) +{ + lockdep_assert_held(&wiphy->mtx); + + hrtimer_cancel(&hrwork->timer); + wiphy_work_flush(wiphy, &hrwork->work); +} +EXPORT_SYMBOL_GPL(wiphy_hrtimer_work_flush); + +bool wiphy_hrtimer_work_pending(struct wiphy *wiphy, + struct wiphy_hrtimer_work *hrwork) +{ + return hrtimer_is_queued(&hrwork->timer); +} +EXPORT_SYMBOL_GPL(wiphy_hrtimer_work_pending); + static int __init cfg80211_init(void) { int err; diff --git a/net/wireless/trace.h b/net/wireless/trace.h index 97c21b627791a..945013185c986 100644 --- a/net/wireless/trace.h +++ b/net/wireless/trace.h @@ -304,6 +304,27 @@ TRACE_EVENT(wiphy_delayed_work_queue, __entry->delay) );

+TRACE_EVENT(wiphy_hrtimer_work_queue, + TP_PROTO(struct wiphy *wiphy, struct wiphy_work *work, + ktime_t delay), + TP_ARGS(wiphy, work, delay), + TP_STRUCT__entry( + WIPHY_ENTRY + __field(void *, instance) + __field(void *, func) + __field(ktime_t, delay) + ), + TP_fast_assign( + WIPHY_ASSIGN; + __entry->instance = work; + __entry->func = work->func; + __entry->delay = delay; + ), + TP_printk(WIPHY_PR_FMT " instance=%p func=%pS delay=%llu", + WIPHY_PR_ARG, __entry->instance, __entry->func, + __entry->delay) +); + TRACE_EVENT(wiphy_work_worker_start, TP_PROTO(struct wiphy *wiphy), TP_ARGS(wiphy),