/* SPDX-License-Identifier: GPL-2.0 */ /* * RT Mutexes: blocking mutual exclusion locks with PI support * * started by Ingo Molnar and Thomas Gleixner: * * Copyright (C) 2004-2006 Red Hat, Inc., Ingo Molnar <[email protected]> * Copyright (C) 2006, Timesys Corp., Thomas Gleixner <[email protected]> * * This file contains the private data structure and API definitions. */ #ifndef __KERNEL_RTMUTEX_COMMON_H #define __KERNEL_RTMUTEX_COMMON_H #include <linux/debug_locks.h> #include <linux/rtmutex.h> #include <linux/sched/wake_q.h> /* * This is a helper for the struct rt_mutex_waiter below. A waiter goes in two * separate trees and they need their own copy of the sort keys because of * different locking requirements. * * @entry: rbtree node to enqueue into the waiters tree * @prio: Priority of the waiter * @deadline: Deadline of the waiter if applicable * * See rt_waiter_node_less() and waiter_*_prio(). */ struct rt_waiter_node { … }; /* * This is the control structure for tasks blocked on a rt_mutex, * which is allocated on the kernel stack on of the blocked task. * * @tree: node to enqueue into the mutex waiters tree * @pi_tree: node to enqueue into the mutex owner waiters tree * @task: task reference to the blocked task * @lock: Pointer to the rt_mutex on which the waiter blocks * @wake_state: Wakeup state to use (TASK_NORMAL or TASK_RTLOCK_WAIT) * @ww_ctx: WW context pointer * * @tree is ordered by @lock->wait_lock * @pi_tree is ordered by rt_mutex_owner(@lock)->pi_lock */ struct rt_mutex_waiter { … }; /** * 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 * @rtlock_task: Task pointer for RT lock (spin/rwlock) wakeups */ struct rt_wake_q_head { … }; #define DEFINE_RT_WAKE_Q(name) … /* * PI-futex support (proxy locking functions, etc.): */ extern void rt_mutex_init_proxy_locked(struct rt_mutex_base *lock, struct task_struct *proxy_owner); extern void rt_mutex_proxy_unlock(struct rt_mutex_base *lock); extern int __rt_mutex_start_proxy_lock(struct rt_mutex_base *lock, struct rt_mutex_waiter *waiter, struct task_struct *task); extern int rt_mutex_start_proxy_lock(struct rt_mutex_base *lock, struct rt_mutex_waiter *waiter, struct task_struct *task); extern int rt_mutex_wait_proxy_lock(struct rt_mutex_base *lock, struct hrtimer_sleeper *to, struct rt_mutex_waiter *waiter); extern bool rt_mutex_cleanup_proxy_lock(struct rt_mutex_base *lock, struct rt_mutex_waiter *waiter); extern int rt_mutex_futex_trylock(struct rt_mutex_base *l); extern int __rt_mutex_futex_trylock(struct rt_mutex_base *l); extern void rt_mutex_futex_unlock(struct rt_mutex_base *lock); extern bool __rt_mutex_futex_unlock(struct rt_mutex_base *lock, struct rt_wake_q_head *wqh); extern void rt_mutex_postunlock(struct rt_wake_q_head *wqh); /* * Must be guarded because this header is included from rcu/tree_plugin.h * unconditionally. */ #ifdef CONFIG_RT_MUTEXES static inline int rt_mutex_has_waiters(struct rt_mutex_base *lock) { … } /* * Lockless speculative check whether @waiter is still the top waiter on * @lock. This is solely comparing pointers and not derefencing the * leftmost entry which might be about to vanish. */ static inline bool rt_mutex_waiter_is_top_waiter(struct rt_mutex_base *lock, struct rt_mutex_waiter *waiter) { … } static inline struct rt_mutex_waiter *rt_mutex_top_waiter(struct rt_mutex_base *lock) { … } static inline int task_has_pi_waiters(struct task_struct *p) { … } static inline struct rt_mutex_waiter *task_top_pi_waiter(struct task_struct *p) { … } #define RT_MUTEX_HAS_WAITERS … static inline struct task_struct *rt_mutex_owner(struct rt_mutex_base *lock) { … } /* * Constants for rt mutex functions which have a selectable deadlock * detection. * * RT_MUTEX_MIN_CHAINWALK: Stops the lock chain walk when there are * no further PI adjustments to be made. * * RT_MUTEX_FULL_CHAINWALK: Invoke deadlock detection with a full * walk of the lock chain. */ enum rtmutex_chainwalk { … }; static inline void __rt_mutex_base_init(struct rt_mutex_base *lock) { … } /* Debug functions */ static inline void debug_rt_mutex_unlock(struct rt_mutex_base *lock) { … } static inline void debug_rt_mutex_proxy_unlock(struct rt_mutex_base *lock) { … } static inline void debug_rt_mutex_init_waiter(struct rt_mutex_waiter *waiter) { … } static inline void debug_rt_mutex_free_waiter(struct rt_mutex_waiter *waiter) { … } static inline void rt_mutex_init_waiter(struct rt_mutex_waiter *waiter) { … } static inline void rt_mutex_init_rtlock_waiter(struct rt_mutex_waiter *waiter) { … } #else /* CONFIG_RT_MUTEXES */ /* Used in rcu/tree_plugin.h */ static inline struct task_struct *rt_mutex_owner(struct rt_mutex_base *lock) { return NULL; } #endif /* !CONFIG_RT_MUTEXES */ #endif
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