/* 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 <mingo@redhat.com> *  Copyright (C) 2006, Timesys Corp., Thomas Gleixner <tglx@timesys.com> * * 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 {	struct rb_node	entry;	int		prio;	u64		deadline;}; /* * 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 {	struct rt_waiter_node	tree;	struct rt_waiter_node	pi_tree;	struct task_struct	*task;	struct rt_mutex_base	*lock;	unsigned int		wake_state;	struct ww_acquire_ctx	*ww_ctx;}; /** * struct 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 {	struct wake_q_head	head;	struct task_struct	*rtlock_task;}; #define DEFINE_RT_WAKE_Q(name)						\	struct rt_wake_q_head name = {					\		.head		= WAKE_Q_HEAD_INITIALIZER(name.head),	\		.rtlock_task	= NULL,					\	} /* * 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,				     struct wake_q_head *);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_MUTEXESstatic inline int rt_mutex_has_waiters(struct rt_mutex_base *lock){	return !RB_EMPTY_ROOT(&lock->waiters.rb_root);} /* * 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){	struct rb_node *leftmost = rb_first_cached(&lock->waiters); 	return rb_entry(leftmost, struct rt_mutex_waiter, tree.entry) == waiter;} static inline struct rt_mutex_waiter *rt_mutex_top_waiter(struct rt_mutex_base *lock){	struct rb_node *leftmost = rb_first_cached(&lock->waiters);	struct rt_mutex_waiter *w = NULL; 	lockdep_assert_held(&lock->wait_lock); 	if (leftmost) {		w = rb_entry(leftmost, struct rt_mutex_waiter, tree.entry);		BUG_ON(w->lock != lock);	}	return w;} static inline int task_has_pi_waiters(struct task_struct *p){	return !RB_EMPTY_ROOT(&p->pi_waiters.rb_root);} static inline struct rt_mutex_waiter *task_top_pi_waiter(struct task_struct *p){	lockdep_assert_held(&p->pi_lock); 	return rb_entry(p->pi_waiters.rb_leftmost, struct rt_mutex_waiter,			pi_tree.entry);} #define RT_MUTEX_HAS_WAITERS	1UL static inline struct task_struct *rt_mutex_owner(struct rt_mutex_base *lock){	unsigned long owner = (unsigned long) READ_ONCE(lock->owner); 	return (struct task_struct *) (owner & ~RT_MUTEX_HAS_WAITERS);} /* * 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 {	RT_MUTEX_MIN_CHAINWALK,	RT_MUTEX_FULL_CHAINWALK,}; static inline void __rt_mutex_base_init(struct rt_mutex_base *lock){	raw_spin_lock_init(&lock->wait_lock);	lock->waiters = RB_ROOT_CACHED;	lock->owner = NULL;} /* Debug functions */static inline void debug_rt_mutex_unlock(struct rt_mutex_base *lock){	if (IS_ENABLED(CONFIG_DEBUG_RT_MUTEXES))		DEBUG_LOCKS_WARN_ON(rt_mutex_owner(lock) != current);} static inline void debug_rt_mutex_proxy_unlock(struct rt_mutex_base *lock){	if (IS_ENABLED(CONFIG_DEBUG_RT_MUTEXES))		DEBUG_LOCKS_WARN_ON(!rt_mutex_owner(lock));} static inline void debug_rt_mutex_init_waiter(struct rt_mutex_waiter *waiter){	if (IS_ENABLED(CONFIG_DEBUG_RT_MUTEXES))		memset(waiter, 0x11, sizeof(*waiter));} static inline void debug_rt_mutex_free_waiter(struct rt_mutex_waiter *waiter){	if (IS_ENABLED(CONFIG_DEBUG_RT_MUTEXES))		memset(waiter, 0x22, sizeof(*waiter));} static inline void rt_mutex_init_waiter(struct rt_mutex_waiter *waiter){	debug_rt_mutex_init_waiter(waiter);	RB_CLEAR_NODE(&waiter->pi_tree.entry);	RB_CLEAR_NODE(&waiter->tree.entry);	waiter->wake_state = TASK_NORMAL;	waiter->task = NULL;} static inline void rt_mutex_init_rtlock_waiter(struct rt_mutex_waiter *waiter){	rt_mutex_init_waiter(waiter);	waiter->wake_state = TASK_RTLOCK_WAIT;} #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