diff options
Diffstat (limited to 'include/linux/hrtimer.h')
| -rw-r--r-- | include/linux/hrtimer.h | 41 |
1 files changed, 16 insertions, 25 deletions
diff --git a/include/linux/hrtimer.h b/include/linux/hrtimer.h index 2f9e57d3d126..5db055821ef3 100644 --- a/include/linux/hrtimer.h +++ b/include/linux/hrtimer.h @@ -53,30 +53,25 @@ enum hrtimer_restart { * * 0x00 inactive * 0x01 enqueued into rbtree - * 0x02 callback function running - * 0x04 timer is migrated to another cpu * - * Special cases: - * 0x03 callback function running and enqueued - * (was requeued on another CPU) - * 0x05 timer was migrated on CPU hotunplug + * The callback state is not part of the timer->state because clearing it would + * mean touching the timer after the callback, this makes it impossible to free + * the timer from the callback function. * - * The "callback function running and enqueued" status is only possible on - * SMP. It happens for example when a posix timer expired and the callback + * Therefore we track the callback state in: + * + * timer->base->cpu_base->running == timer + * + * On SMP it is possible to have a "callback function running and enqueued" + * status. It happens for example when a posix timer expired and the callback * queued a signal. Between dropping the lock which protects the posix timer * and reacquiring the base lock of the hrtimer, another CPU can deliver the - * signal and rearm the timer. We have to preserve the callback running state, - * as otherwise the timer could be removed before the softirq code finishes the - * the handling of the timer. - * - * The HRTIMER_STATE_ENQUEUED bit is always or'ed to the current state - * to preserve the HRTIMER_STATE_CALLBACK in the above scenario. + * signal and rearm the timer. * * All state transitions are protected by cpu_base->lock. */ #define HRTIMER_STATE_INACTIVE 0x00 #define HRTIMER_STATE_ENQUEUED 0x01 -#define HRTIMER_STATE_CALLBACK 0x02 /** * struct hrtimer - the basic hrtimer structure @@ -163,6 +158,8 @@ enum hrtimer_base_type { * struct hrtimer_cpu_base - the per cpu clock bases * @lock: lock protecting the base and associated clock bases * and timers + * @seq: seqcount around __run_hrtimer + * @running: pointer to the currently running hrtimer * @cpu: cpu number * @active_bases: Bitfield to mark bases with active timers * @clock_was_set_seq: Sequence counter of clock was set events @@ -184,6 +181,8 @@ enum hrtimer_base_type { */ struct hrtimer_cpu_base { raw_spinlock_t lock; + seqcount_t seq; + struct hrtimer *running; unsigned int cpu; unsigned int active_bases; unsigned int clock_was_set_seq; @@ -391,15 +390,7 @@ extern ktime_t hrtimer_get_remaining(const struct hrtimer *timer); extern u64 hrtimer_get_next_event(void); -/* - * A timer is active, when it is enqueued into the rbtree or the - * callback function is running or it's in the state of being migrated - * to another cpu. - */ -static inline int hrtimer_active(const struct hrtimer *timer) -{ - return timer->state != HRTIMER_STATE_INACTIVE; -} +extern bool hrtimer_active(const struct hrtimer *timer); /* * Helper function to check, whether the timer is on one of the queues @@ -415,7 +406,7 @@ static inline int hrtimer_is_queued(struct hrtimer *timer) */ static inline int hrtimer_callback_running(struct hrtimer *timer) { - return timer->state & HRTIMER_STATE_CALLBACK; + return timer->base->cpu_base->running == timer; } /* Forward a hrtimer so it expires after now: */ |