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Linux kernel mirror (for testing) git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
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123456789101112131415161718192021222324252627282930313233343536373839404142434445464748495051525354555657585960616263646566676869707172737475767778798081828384858687888990919293949596979899100101102103104105106107108109110111112113114115116117118119120121122123124125126127128129130131132133134135136137138139140141142143144145146147148149150151152153154155156157158159160161162163164165166167168169170171172173174175176177178179180181182183184185186187188189190191192193194195196197198199200201202203204205206207208209210211212213214215216217218219220221222223224225226227228229230231232233234235236237238/* 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) __must_hold(&lock->wait_lock);
extern void rt_mutex_proxy_unlock(struct rt_mutex_base *lock) __must_hold(&lock->wait_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 *) __must_hold(&lock->wait_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_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 *lock);extern int __rt_mutex_futex_trylock(struct rt_mutex_base *lock) __must_hold(&lock->wait_lock);
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) __must_hold(&lock->wait_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) __must_hold(&lock->wait_lock){ 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) __must_hold(&lock->wait_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);}
/* * 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){ scoped_guard (raw_spinlock_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