diff options
Diffstat (limited to 'include/linux/sched/wake_q.h')
| -rw-r--r-- | include/linux/sched/wake_q.h | 57 |
1 files changed, 52 insertions, 5 deletions
diff --git a/include/linux/sched/wake_q.h b/include/linux/sched/wake_q.h index d03d8a9047dc..0f28b4623ad4 100644 --- a/include/linux/sched/wake_q.h +++ b/include/linux/sched/wake_q.h @@ -1,3 +1,4 @@ +/* SPDX-License-Identifier: GPL-2.0 */ #ifndef _LINUX_SCHED_WAKE_Q_H #define _LINUX_SCHED_WAKE_Q_H @@ -23,9 +24,13 @@ * called near the end of a function. Otherwise, the list can be * re-initialized for later re-use by wake_q_init(). * - * Note that this can cause spurious wakeups. schedule() callers + * NOTE that this can cause spurious wakeups. schedule() callers * must ensure the call is done inside a loop, confirming that the * wakeup condition has in fact occurred. + * + * NOTE that there is no guarantee the wakeup will happen any later than the + * wake_q_add() location. Therefore task must be ready to be woken at the + * location of the wake_q_add(). */ #include <linux/sched.h> @@ -37,8 +42,11 @@ struct wake_q_head { #define WAKE_Q_TAIL ((struct wake_q_node *) 0x01) -#define DEFINE_WAKE_Q(name) \ - struct wake_q_head name = { WAKE_Q_TAIL, &name.first } +#define WAKE_Q_HEAD_INITIALIZER(name) \ + { WAKE_Q_TAIL, &name.first } + +#define DEFINE_WAKE_Q(name) \ + struct wake_q_head name = WAKE_Q_HEAD_INITIALIZER(name) static inline void wake_q_init(struct wake_q_head *head) { @@ -46,8 +54,47 @@ static inline void wake_q_init(struct wake_q_head *head) head->lastp = &head->first; } -extern void wake_q_add(struct wake_q_head *head, - struct task_struct *task); +static inline bool wake_q_empty(struct wake_q_head *head) +{ + return head->first == WAKE_Q_TAIL; +} + +extern void wake_q_add(struct wake_q_head *head, struct task_struct *task); +extern void wake_q_add_safe(struct wake_q_head *head, struct task_struct *task); extern void wake_up_q(struct wake_q_head *head); +/* Spin unlock helpers to unlock and call wake_up_q with preempt disabled */ +static inline +void raw_spin_unlock_wake(raw_spinlock_t *lock, struct wake_q_head *wake_q) +{ + guard(preempt)(); + raw_spin_unlock(lock); + if (wake_q) { + wake_up_q(wake_q); + wake_q_init(wake_q); + } +} + +static inline +void raw_spin_unlock_irq_wake(raw_spinlock_t *lock, struct wake_q_head *wake_q) +{ + guard(preempt)(); + raw_spin_unlock_irq(lock); + if (wake_q) { + wake_up_q(wake_q); + wake_q_init(wake_q); + } +} + +static inline +void raw_spin_unlock_irqrestore_wake(raw_spinlock_t *lock, unsigned long flags, + struct wake_q_head *wake_q) +{ + guard(preempt)(); + raw_spin_unlock_irqrestore(lock, flags); + if (wake_q) { + wake_up_q(wake_q); + wake_q_init(wake_q); + } +} #endif /* _LINUX_SCHED_WAKE_Q_H */ |