/* 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/rtmutex.h>#include <linux/sched/wake_q.h> /* * 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_entry:		pi node to enqueue into the mutex waiters tree * @pi_tree_entry:	pi node to enqueue into the mutex owner waiters tree * @task:		task reference to the blocked task */struct rt_mutex_waiter {	struct rb_node          tree_entry;	struct rb_node          pi_tree_entry;	struct task_struct	*task;	struct rt_mutex		*lock;#ifdef CONFIG_DEBUG_RT_MUTEXES	unsigned long		ip;	struct pid		*deadlock_task_pid;	struct rt_mutex		*deadlock_lock;#endif	int prio;	u64 deadline;}; /* * Various helpers to access the waiters-tree: */ #ifdef CONFIG_RT_MUTEXES static inline int rt_mutex_has_waiters(struct rt_mutex *lock){	return !RB_EMPTY_ROOT(&lock->waiters.rb_root);} static inline struct rt_mutex_waiter *rt_mutex_top_waiter(struct rt_mutex *lock){	struct rt_mutex_waiter *w; 	w = rb_entry(lock->waiters.rb_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){	return rb_entry(p->pi_waiters.rb_leftmost,			struct rt_mutex_waiter, pi_tree_entry);} #else static inline int rt_mutex_has_waiters(struct rt_mutex *lock){	return false;} static inline struct rt_mutex_waiter *rt_mutex_top_waiter(struct rt_mutex *lock){	return NULL;} static inline int task_has_pi_waiters(struct task_struct *p){	return false;} static inline struct rt_mutex_waiter *task_top_pi_waiter(struct task_struct *p){	return NULL;} #endif /* * lock->owner state tracking: */#define RT_MUTEX_HAS_WAITERS	1UL static inline struct task_struct *rt_mutex_owner(struct rt_mutex *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,}; /* * PI-futex support (proxy locking functions, etc.): */extern struct task_struct *rt_mutex_next_owner(struct rt_mutex *lock);extern void rt_mutex_init_proxy_locked(struct rt_mutex *lock,				       struct task_struct *proxy_owner);extern void rt_mutex_proxy_unlock(struct rt_mutex *lock,				  struct task_struct *proxy_owner);extern void rt_mutex_init_waiter(struct rt_mutex_waiter *waiter);extern int __rt_mutex_start_proxy_lock(struct rt_mutex *lock,				     struct rt_mutex_waiter *waiter,				     struct task_struct *task);extern int rt_mutex_start_proxy_lock(struct rt_mutex *lock,				     struct rt_mutex_waiter *waiter,				     struct task_struct *task);extern int rt_mutex_wait_proxy_lock(struct rt_mutex *lock,			       struct hrtimer_sleeper *to,			       struct rt_mutex_waiter *waiter);extern bool rt_mutex_cleanup_proxy_lock(struct rt_mutex *lock,				 struct rt_mutex_waiter *waiter); extern int rt_mutex_futex_trylock(struct rt_mutex *l); extern void rt_mutex_futex_unlock(struct rt_mutex *lock);extern bool __rt_mutex_futex_unlock(struct rt_mutex *lock,				 struct wake_q_head *wqh); extern void rt_mutex_postunlock(struct wake_q_head *wake_q); #ifdef CONFIG_DEBUG_RT_MUTEXES# include "rtmutex-debug.h"#else# include "rtmutex.h"#endif #endif