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locking/rtmutex: Provide rt_wake_q_head and helpers 

To handle the difference between wakeups for regular sleeping locks (mutex,
rtmutex, rw_semaphore) and the wakeups for 'sleeping' spin/rwlocks on
PREEMPT_RT enabled kernels correctly, it is required to provide a
wake_q_head construct which allows to keep them separate.

Provide a wrapper around wake_q_head and the required helpers, which will be
extended with the state handling later.

No functional change.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Link: https://lore.kernel.org/r/20210815211303.139337655@linutronix.de
This commit is contained in:
Thomas Gleixner 2021-08-15 23:28:08 +02:00 committed by Ingo Molnar
parent c014ef69b3
commit b576e640ce
2 changed files with 29 additions and 0 deletions
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15
kernel/locking/rtmutex.c
View File

@ -347,6 +347,21 @@ static __always_inline void rt_mutex_adjust_prio(struct task_struct *p)
rt_mutex_setprio(p, pi_task);
}
/* RT mutex specific wake_q wrappers */
static __always_inline void rt_mutex_wake_q_add(struct rt_wake_q_head *wqh,
struct rt_mutex_waiter *w)
{
wake_q_add(&wqh->head, w->task);
}
static __always_inline void rt_mutex_wake_up_q(struct rt_wake_q_head *wqh)
{
wake_up_q(&wqh->head);
/* Pairs with preempt_disable() in mark_wakeup_next_waiter() */
preempt_enable();
}
/*
* Deadlock detection is conditional:
*

14
kernel/locking/rtmutex_common.h
View File

@ -39,6 +39,20 @@ struct rt_mutex_waiter {
u64 deadline;
};
/**
* rt_wake_q_head - Wrapper around regular wake_q_head to support
* "sleeping" spinlocks on RT
* @head: The regular wake_q_head for sleeping lock variants
*/
struct rt_wake_q_head {
struct wake_q_head head;
};
#define DEFINE_RT_WAKE_Q(name) \
struct rt_wake_q_head name = { \
.head = WAKE_Q_HEAD_INITIALIZER(name.head), \
}
/*
* PI-futex support (proxy locking functions, etc.):
*/