diff options
Diffstat (limited to 'kernel/rtmutex.c')
| -rw-r--r-- | kernel/rtmutex.c | 1060 | 
1 files changed, 0 insertions, 1060 deletions
diff --git a/kernel/rtmutex.c b/kernel/rtmutex.c deleted file mode 100644 index 0dd6aec1cb6..00000000000 --- a/kernel/rtmutex.c +++ /dev/null @@ -1,1060 +0,0 @@ -/* - * RT-Mutexes: simple 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) 2005-2006 Timesys Corp., Thomas Gleixner <tglx@timesys.com> - *  Copyright (C) 2005 Kihon Technologies Inc., Steven Rostedt - *  Copyright (C) 2006 Esben Nielsen - * - *  See Documentation/rt-mutex-design.txt for details. - */ -#include <linux/spinlock.h> -#include <linux/export.h> -#include <linux/sched.h> -#include <linux/sched/rt.h> -#include <linux/timer.h> - -#include "rtmutex_common.h" - -/* - * lock->owner state tracking: - * - * lock->owner holds the task_struct pointer of the owner. Bit 0 - * is used to keep track of the "lock has waiters" state. - * - * owner	bit0 - * NULL		0	lock is free (fast acquire possible) - * NULL		1	lock is free and has waiters and the top waiter - *				is going to take the lock* - * taskpointer	0	lock is held (fast release possible) - * taskpointer	1	lock is held and has waiters** - * - * The fast atomic compare exchange based acquire and release is only - * possible when bit 0 of lock->owner is 0. - * - * (*) It also can be a transitional state when grabbing the lock - * with ->wait_lock is held. To prevent any fast path cmpxchg to the lock, - * we need to set the bit0 before looking at the lock, and the owner may be - * NULL in this small time, hence this can be a transitional state. - * - * (**) There is a small time when bit 0 is set but there are no - * waiters. This can happen when grabbing the lock in the slow path. - * To prevent a cmpxchg of the owner releasing the lock, we need to - * set this bit before looking at the lock. - */ - -static void -rt_mutex_set_owner(struct rt_mutex *lock, struct task_struct *owner) -{ -	unsigned long val = (unsigned long)owner; - -	if (rt_mutex_has_waiters(lock)) -		val |= RT_MUTEX_HAS_WAITERS; - -	lock->owner = (struct task_struct *)val; -} - -static inline void clear_rt_mutex_waiters(struct rt_mutex *lock) -{ -	lock->owner = (struct task_struct *) -			((unsigned long)lock->owner & ~RT_MUTEX_HAS_WAITERS); -} - -static void fixup_rt_mutex_waiters(struct rt_mutex *lock) -{ -	if (!rt_mutex_has_waiters(lock)) -		clear_rt_mutex_waiters(lock); -} - -/* - * We can speed up the acquire/release, if the architecture - * supports cmpxchg and if there's no debugging state to be set up - */ -#if defined(__HAVE_ARCH_CMPXCHG) && !defined(CONFIG_DEBUG_RT_MUTEXES) -# define rt_mutex_cmpxchg(l,c,n)	(cmpxchg(&l->owner, c, n) == c) -static inline void mark_rt_mutex_waiters(struct rt_mutex *lock) -{ -	unsigned long owner, *p = (unsigned long *) &lock->owner; - -	do { -		owner = *p; -	} while (cmpxchg(p, owner, owner | RT_MUTEX_HAS_WAITERS) != owner); -} -#else -# define rt_mutex_cmpxchg(l,c,n)	(0) -static inline void mark_rt_mutex_waiters(struct rt_mutex *lock) -{ -	lock->owner = (struct task_struct *) -			((unsigned long)lock->owner | RT_MUTEX_HAS_WAITERS); -} -#endif - -/* - * Calculate task priority from the waiter list priority - * - * Return task->normal_prio when the waiter list is empty or when - * the waiter is not allowed to do priority boosting - */ -int rt_mutex_getprio(struct task_struct *task) -{ -	if (likely(!task_has_pi_waiters(task))) -		return task->normal_prio; - -	return min(task_top_pi_waiter(task)->pi_list_entry.prio, -		   task->normal_prio); -} - -/* - * Adjust the priority of a task, after its pi_waiters got modified. - * - * This can be both boosting and unboosting. task->pi_lock must be held. - */ -static void __rt_mutex_adjust_prio(struct task_struct *task) -{ -	int prio = rt_mutex_getprio(task); - -	if (task->prio != prio) -		rt_mutex_setprio(task, prio); -} - -/* - * Adjust task priority (undo boosting). Called from the exit path of - * rt_mutex_slowunlock() and rt_mutex_slowlock(). - * - * (Note: We do this outside of the protection of lock->wait_lock to - * allow the lock to be taken while or before we readjust the priority - * of task. We do not use the spin_xx_mutex() variants here as we are - * outside of the debug path.) - */ -static void rt_mutex_adjust_prio(struct task_struct *task) -{ -	unsigned long flags; - -	raw_spin_lock_irqsave(&task->pi_lock, flags); -	__rt_mutex_adjust_prio(task); -	raw_spin_unlock_irqrestore(&task->pi_lock, flags); -} - -/* - * Max number of times we'll walk the boosting chain: - */ -int max_lock_depth = 1024; - -/* - * Adjust the priority chain. Also used for deadlock detection. - * Decreases task's usage by one - may thus free the task. - * - * @task: the task owning the mutex (owner) for which a chain walk is probably - *	  needed - * @deadlock_detect: do we have to carry out deadlock detection? - * @orig_lock: the mutex (can be NULL if we are walking the chain to recheck - * 	       things for a task that has just got its priority adjusted, and - *	       is waiting on a mutex) - * @orig_waiter: rt_mutex_waiter struct for the task that has just donated - *		 its priority to the mutex owner (can be NULL in the case - *		 depicted above or if the top waiter is gone away and we are - *		 actually deboosting the owner) - * @top_task: the current top waiter - * - * Returns 0 or -EDEADLK. - */ -static int rt_mutex_adjust_prio_chain(struct task_struct *task, -				      int deadlock_detect, -				      struct rt_mutex *orig_lock, -				      struct rt_mutex_waiter *orig_waiter, -				      struct task_struct *top_task) -{ -	struct rt_mutex *lock; -	struct rt_mutex_waiter *waiter, *top_waiter = orig_waiter; -	int detect_deadlock, ret = 0, depth = 0; -	unsigned long flags; - -	detect_deadlock = debug_rt_mutex_detect_deadlock(orig_waiter, -							 deadlock_detect); - -	/* -	 * The (de)boosting is a step by step approach with a lot of -	 * pitfalls. We want this to be preemptible and we want hold a -	 * maximum of two locks per step. So we have to check -	 * carefully whether things change under us. -	 */ - again: -	if (++depth > max_lock_depth) { -		static int prev_max; - -		/* -		 * Print this only once. If the admin changes the limit, -		 * print a new message when reaching the limit again. -		 */ -		if (prev_max != max_lock_depth) { -			prev_max = max_lock_depth; -			printk(KERN_WARNING "Maximum lock depth %d reached " -			       "task: %s (%d)\n", max_lock_depth, -			       top_task->comm, task_pid_nr(top_task)); -		} -		put_task_struct(task); - -		return deadlock_detect ? -EDEADLK : 0; -	} - retry: -	/* -	 * Task can not go away as we did a get_task() before ! -	 */ -	raw_spin_lock_irqsave(&task->pi_lock, flags); - -	waiter = task->pi_blocked_on; -	/* -	 * Check whether the end of the boosting chain has been -	 * reached or the state of the chain has changed while we -	 * dropped the locks. -	 */ -	if (!waiter) -		goto out_unlock_pi; - -	/* -	 * Check the orig_waiter state. After we dropped the locks, -	 * the previous owner of the lock might have released the lock. -	 */ -	if (orig_waiter && !rt_mutex_owner(orig_lock)) -		goto out_unlock_pi; - -	/* -	 * Drop out, when the task has no waiters. Note, -	 * top_waiter can be NULL, when we are in the deboosting -	 * mode! -	 */ -	if (top_waiter && (!task_has_pi_waiters(task) || -			   top_waiter != task_top_pi_waiter(task))) -		goto out_unlock_pi; - -	/* -	 * When deadlock detection is off then we check, if further -	 * priority adjustment is necessary. -	 */ -	if (!detect_deadlock && waiter->list_entry.prio == task->prio) -		goto out_unlock_pi; - -	lock = waiter->lock; -	if (!raw_spin_trylock(&lock->wait_lock)) { -		raw_spin_unlock_irqrestore(&task->pi_lock, flags); -		cpu_relax(); -		goto retry; -	} - -	/* Deadlock detection */ -	if (lock == orig_lock || rt_mutex_owner(lock) == top_task) { -		debug_rt_mutex_deadlock(deadlock_detect, orig_waiter, lock); -		raw_spin_unlock(&lock->wait_lock); -		ret = deadlock_detect ? -EDEADLK : 0; -		goto out_unlock_pi; -	} - -	top_waiter = rt_mutex_top_waiter(lock); - -	/* Requeue the waiter */ -	plist_del(&waiter->list_entry, &lock->wait_list); -	waiter->list_entry.prio = task->prio; -	plist_add(&waiter->list_entry, &lock->wait_list); - -	/* Release the task */ -	raw_spin_unlock_irqrestore(&task->pi_lock, flags); -	if (!rt_mutex_owner(lock)) { -		/* -		 * If the requeue above changed the top waiter, then we need -		 * to wake the new top waiter up to try to get the lock. -		 */ - -		if (top_waiter != rt_mutex_top_waiter(lock)) -			wake_up_process(rt_mutex_top_waiter(lock)->task); -		raw_spin_unlock(&lock->wait_lock); -		goto out_put_task; -	} -	put_task_struct(task); - -	/* Grab the next task */ -	task = rt_mutex_owner(lock); -	get_task_struct(task); -	raw_spin_lock_irqsave(&task->pi_lock, flags); - -	if (waiter == rt_mutex_top_waiter(lock)) { -		/* Boost the owner */ -		plist_del(&top_waiter->pi_list_entry, &task->pi_waiters); -		waiter->pi_list_entry.prio = waiter->list_entry.prio; -		plist_add(&waiter->pi_list_entry, &task->pi_waiters); -		__rt_mutex_adjust_prio(task); - -	} else if (top_waiter == waiter) { -		/* Deboost the owner */ -		plist_del(&waiter->pi_list_entry, &task->pi_waiters); -		waiter = rt_mutex_top_waiter(lock); -		waiter->pi_list_entry.prio = waiter->list_entry.prio; -		plist_add(&waiter->pi_list_entry, &task->pi_waiters); -		__rt_mutex_adjust_prio(task); -	} - -	raw_spin_unlock_irqrestore(&task->pi_lock, flags); - -	top_waiter = rt_mutex_top_waiter(lock); -	raw_spin_unlock(&lock->wait_lock); - -	if (!detect_deadlock && waiter != top_waiter) -		goto out_put_task; - -	goto again; - - out_unlock_pi: -	raw_spin_unlock_irqrestore(&task->pi_lock, flags); - out_put_task: -	put_task_struct(task); - -	return ret; -} - -/* - * Try to take an rt-mutex - * - * Must be called with lock->wait_lock held. - * - * @lock:   the lock to be acquired. - * @task:   the task which wants to acquire the lock - * @waiter: the waiter that is queued to the lock's wait list. (could be NULL) - */ -static int try_to_take_rt_mutex(struct rt_mutex *lock, struct task_struct *task, -		struct rt_mutex_waiter *waiter) -{ -	/* -	 * We have to be careful here if the atomic speedups are -	 * enabled, such that, when -	 *  - no other waiter is on the lock -	 *  - the lock has been released since we did the cmpxchg -	 * the lock can be released or taken while we are doing the -	 * checks and marking the lock with RT_MUTEX_HAS_WAITERS. -	 * -	 * The atomic acquire/release aware variant of -	 * mark_rt_mutex_waiters uses a cmpxchg loop. After setting -	 * the WAITERS bit, the atomic release / acquire can not -	 * happen anymore and lock->wait_lock protects us from the -	 * non-atomic case. -	 * -	 * Note, that this might set lock->owner = -	 * RT_MUTEX_HAS_WAITERS in the case the lock is not contended -	 * any more. This is fixed up when we take the ownership. -	 * This is the transitional state explained at the top of this file. -	 */ -	mark_rt_mutex_waiters(lock); - -	if (rt_mutex_owner(lock)) -		return 0; - -	/* -	 * It will get the lock because of one of these conditions: -	 * 1) there is no waiter -	 * 2) higher priority than waiters -	 * 3) it is top waiter -	 */ -	if (rt_mutex_has_waiters(lock)) { -		if (task->prio >= rt_mutex_top_waiter(lock)->list_entry.prio) { -			if (!waiter || waiter != rt_mutex_top_waiter(lock)) -				return 0; -		} -	} - -	if (waiter || rt_mutex_has_waiters(lock)) { -		unsigned long flags; -		struct rt_mutex_waiter *top; - -		raw_spin_lock_irqsave(&task->pi_lock, flags); - -		/* remove the queued waiter. */ -		if (waiter) { -			plist_del(&waiter->list_entry, &lock->wait_list); -			task->pi_blocked_on = NULL; -		} - -		/* -		 * We have to enqueue the top waiter(if it exists) into -		 * task->pi_waiters list. -		 */ -		if (rt_mutex_has_waiters(lock)) { -			top = rt_mutex_top_waiter(lock); -			top->pi_list_entry.prio = top->list_entry.prio; -			plist_add(&top->pi_list_entry, &task->pi_waiters); -		} -		raw_spin_unlock_irqrestore(&task->pi_lock, flags); -	} - -	/* We got the lock. */ -	debug_rt_mutex_lock(lock); - -	rt_mutex_set_owner(lock, task); - -	rt_mutex_deadlock_account_lock(lock, task); - -	return 1; -} - -/* - * Task blocks on lock. - * - * Prepare waiter and propagate pi chain - * - * This must be called with lock->wait_lock held. - */ -static int task_blocks_on_rt_mutex(struct rt_mutex *lock, -				   struct rt_mutex_waiter *waiter, -				   struct task_struct *task, -				   int detect_deadlock) -{ -	struct task_struct *owner = rt_mutex_owner(lock); -	struct rt_mutex_waiter *top_waiter = waiter; -	unsigned long flags; -	int chain_walk = 0, res; - -	raw_spin_lock_irqsave(&task->pi_lock, flags); -	__rt_mutex_adjust_prio(task); -	waiter->task = task; -	waiter->lock = lock; -	plist_node_init(&waiter->list_entry, task->prio); -	plist_node_init(&waiter->pi_list_entry, task->prio); - -	/* Get the top priority waiter on the lock */ -	if (rt_mutex_has_waiters(lock)) -		top_waiter = rt_mutex_top_waiter(lock); -	plist_add(&waiter->list_entry, &lock->wait_list); - -	task->pi_blocked_on = waiter; - -	raw_spin_unlock_irqrestore(&task->pi_lock, flags); - -	if (!owner) -		return 0; - -	if (waiter == rt_mutex_top_waiter(lock)) { -		raw_spin_lock_irqsave(&owner->pi_lock, flags); -		plist_del(&top_waiter->pi_list_entry, &owner->pi_waiters); -		plist_add(&waiter->pi_list_entry, &owner->pi_waiters); - -		__rt_mutex_adjust_prio(owner); -		if (owner->pi_blocked_on) -			chain_walk = 1; -		raw_spin_unlock_irqrestore(&owner->pi_lock, flags); -	} -	else if (debug_rt_mutex_detect_deadlock(waiter, detect_deadlock)) -		chain_walk = 1; - -	if (!chain_walk) -		return 0; - -	/* -	 * The owner can't disappear while holding a lock, -	 * so the owner struct is protected by wait_lock. -	 * Gets dropped in rt_mutex_adjust_prio_chain()! -	 */ -	get_task_struct(owner); - -	raw_spin_unlock(&lock->wait_lock); - -	res = rt_mutex_adjust_prio_chain(owner, detect_deadlock, lock, waiter, -					 task); - -	raw_spin_lock(&lock->wait_lock); - -	return res; -} - -/* - * Wake up the next waiter on the lock. - * - * Remove the top waiter from the current tasks waiter list and wake it up. - * - * Called with lock->wait_lock held. - */ -static void wakeup_next_waiter(struct rt_mutex *lock) -{ -	struct rt_mutex_waiter *waiter; -	unsigned long flags; - -	raw_spin_lock_irqsave(¤t->pi_lock, flags); - -	waiter = rt_mutex_top_waiter(lock); - -	/* -	 * Remove it from current->pi_waiters. We do not adjust a -	 * possible priority boost right now. We execute wakeup in the -	 * boosted mode and go back to normal after releasing -	 * lock->wait_lock. -	 */ -	plist_del(&waiter->pi_list_entry, ¤t->pi_waiters); - -	rt_mutex_set_owner(lock, NULL); - -	raw_spin_unlock_irqrestore(¤t->pi_lock, flags); - -	wake_up_process(waiter->task); -} - -/* - * Remove a waiter from a lock and give up - * - * Must be called with lock->wait_lock held and - * have just failed to try_to_take_rt_mutex(). - */ -static void remove_waiter(struct rt_mutex *lock, -			  struct rt_mutex_waiter *waiter) -{ -	int first = (waiter == rt_mutex_top_waiter(lock)); -	struct task_struct *owner = rt_mutex_owner(lock); -	unsigned long flags; -	int chain_walk = 0; - -	raw_spin_lock_irqsave(¤t->pi_lock, flags); -	plist_del(&waiter->list_entry, &lock->wait_list); -	current->pi_blocked_on = NULL; -	raw_spin_unlock_irqrestore(¤t->pi_lock, flags); - -	if (!owner) -		return; - -	if (first) { - -		raw_spin_lock_irqsave(&owner->pi_lock, flags); - -		plist_del(&waiter->pi_list_entry, &owner->pi_waiters); - -		if (rt_mutex_has_waiters(lock)) { -			struct rt_mutex_waiter *next; - -			next = rt_mutex_top_waiter(lock); -			plist_add(&next->pi_list_entry, &owner->pi_waiters); -		} -		__rt_mutex_adjust_prio(owner); - -		if (owner->pi_blocked_on) -			chain_walk = 1; - -		raw_spin_unlock_irqrestore(&owner->pi_lock, flags); -	} - -	WARN_ON(!plist_node_empty(&waiter->pi_list_entry)); - -	if (!chain_walk) -		return; - -	/* gets dropped in rt_mutex_adjust_prio_chain()! */ -	get_task_struct(owner); - -	raw_spin_unlock(&lock->wait_lock); - -	rt_mutex_adjust_prio_chain(owner, 0, lock, NULL, current); - -	raw_spin_lock(&lock->wait_lock); -} - -/* - * Recheck the pi chain, in case we got a priority setting - * - * Called from sched_setscheduler - */ -void rt_mutex_adjust_pi(struct task_struct *task) -{ -	struct rt_mutex_waiter *waiter; -	unsigned long flags; - -	raw_spin_lock_irqsave(&task->pi_lock, flags); - -	waiter = task->pi_blocked_on; -	if (!waiter || waiter->list_entry.prio == task->prio) { -		raw_spin_unlock_irqrestore(&task->pi_lock, flags); -		return; -	} - -	raw_spin_unlock_irqrestore(&task->pi_lock, flags); - -	/* gets dropped in rt_mutex_adjust_prio_chain()! */ -	get_task_struct(task); -	rt_mutex_adjust_prio_chain(task, 0, NULL, NULL, task); -} - -/** - * __rt_mutex_slowlock() - Perform the wait-wake-try-to-take loop - * @lock:		 the rt_mutex to take - * @state:		 the state the task should block in (TASK_INTERRUPTIBLE - * 			 or TASK_UNINTERRUPTIBLE) - * @timeout:		 the pre-initialized and started timer, or NULL for none - * @waiter:		 the pre-initialized rt_mutex_waiter - * - * lock->wait_lock must be held by the caller. - */ -static int __sched -__rt_mutex_slowlock(struct rt_mutex *lock, int state, -		    struct hrtimer_sleeper *timeout, -		    struct rt_mutex_waiter *waiter) -{ -	int ret = 0; - -	for (;;) { -		/* Try to acquire the lock: */ -		if (try_to_take_rt_mutex(lock, current, waiter)) -			break; - -		/* -		 * TASK_INTERRUPTIBLE checks for signals and -		 * timeout. Ignored otherwise. -		 */ -		if (unlikely(state == TASK_INTERRUPTIBLE)) { -			/* Signal pending? */ -			if (signal_pending(current)) -				ret = -EINTR; -			if (timeout && !timeout->task) -				ret = -ETIMEDOUT; -			if (ret) -				break; -		} - -		raw_spin_unlock(&lock->wait_lock); - -		debug_rt_mutex_print_deadlock(waiter); - -		schedule_rt_mutex(lock); - -		raw_spin_lock(&lock->wait_lock); -		set_current_state(state); -	} - -	return ret; -} - -/* - * Slow path lock function: - */ -static int __sched -rt_mutex_slowlock(struct rt_mutex *lock, int state, -		  struct hrtimer_sleeper *timeout, -		  int detect_deadlock) -{ -	struct rt_mutex_waiter waiter; -	int ret = 0; - -	debug_rt_mutex_init_waiter(&waiter); - -	raw_spin_lock(&lock->wait_lock); - -	/* Try to acquire the lock again: */ -	if (try_to_take_rt_mutex(lock, current, NULL)) { -		raw_spin_unlock(&lock->wait_lock); -		return 0; -	} - -	set_current_state(state); - -	/* Setup the timer, when timeout != NULL */ -	if (unlikely(timeout)) { -		hrtimer_start_expires(&timeout->timer, HRTIMER_MODE_ABS); -		if (!hrtimer_active(&timeout->timer)) -			timeout->task = NULL; -	} - -	ret = task_blocks_on_rt_mutex(lock, &waiter, current, detect_deadlock); - -	if (likely(!ret)) -		ret = __rt_mutex_slowlock(lock, state, timeout, &waiter); - -	set_current_state(TASK_RUNNING); - -	if (unlikely(ret)) -		remove_waiter(lock, &waiter); - -	/* -	 * try_to_take_rt_mutex() sets the waiter bit -	 * unconditionally. We might have to fix that up. -	 */ -	fixup_rt_mutex_waiters(lock); - -	raw_spin_unlock(&lock->wait_lock); - -	/* Remove pending timer: */ -	if (unlikely(timeout)) -		hrtimer_cancel(&timeout->timer); - -	debug_rt_mutex_free_waiter(&waiter); - -	return ret; -} - -/* - * Slow path try-lock function: - */ -static inline int -rt_mutex_slowtrylock(struct rt_mutex *lock) -{ -	int ret = 0; - -	raw_spin_lock(&lock->wait_lock); - -	if (likely(rt_mutex_owner(lock) != current)) { - -		ret = try_to_take_rt_mutex(lock, current, NULL); -		/* -		 * try_to_take_rt_mutex() sets the lock waiters -		 * bit unconditionally. Clean this up. -		 */ -		fixup_rt_mutex_waiters(lock); -	} - -	raw_spin_unlock(&lock->wait_lock); - -	return ret; -} - -/* - * Slow path to release a rt-mutex: - */ -static void __sched -rt_mutex_slowunlock(struct rt_mutex *lock) -{ -	raw_spin_lock(&lock->wait_lock); - -	debug_rt_mutex_unlock(lock); - -	rt_mutex_deadlock_account_unlock(current); - -	if (!rt_mutex_has_waiters(lock)) { -		lock->owner = NULL; -		raw_spin_unlock(&lock->wait_lock); -		return; -	} - -	wakeup_next_waiter(lock); - -	raw_spin_unlock(&lock->wait_lock); - -	/* Undo pi boosting if necessary: */ -	rt_mutex_adjust_prio(current); -} - -/* - * debug aware fast / slowpath lock,trylock,unlock - * - * The atomic acquire/release ops are compiled away, when either the - * architecture does not support cmpxchg or when debugging is enabled. - */ -static inline int -rt_mutex_fastlock(struct rt_mutex *lock, int state, -		  int detect_deadlock, -		  int (*slowfn)(struct rt_mutex *lock, int state, -				struct hrtimer_sleeper *timeout, -				int detect_deadlock)) -{ -	if (!detect_deadlock && likely(rt_mutex_cmpxchg(lock, NULL, current))) { -		rt_mutex_deadlock_account_lock(lock, current); -		return 0; -	} else -		return slowfn(lock, state, NULL, detect_deadlock); -} - -static inline int -rt_mutex_timed_fastlock(struct rt_mutex *lock, int state, -			struct hrtimer_sleeper *timeout, int detect_deadlock, -			int (*slowfn)(struct rt_mutex *lock, int state, -				      struct hrtimer_sleeper *timeout, -				      int detect_deadlock)) -{ -	if (!detect_deadlock && likely(rt_mutex_cmpxchg(lock, NULL, current))) { -		rt_mutex_deadlock_account_lock(lock, current); -		return 0; -	} else -		return slowfn(lock, state, timeout, detect_deadlock); -} - -static inline int -rt_mutex_fasttrylock(struct rt_mutex *lock, -		     int (*slowfn)(struct rt_mutex *lock)) -{ -	if (likely(rt_mutex_cmpxchg(lock, NULL, current))) { -		rt_mutex_deadlock_account_lock(lock, current); -		return 1; -	} -	return slowfn(lock); -} - -static inline void -rt_mutex_fastunlock(struct rt_mutex *lock, -		    void (*slowfn)(struct rt_mutex *lock)) -{ -	if (likely(rt_mutex_cmpxchg(lock, current, NULL))) -		rt_mutex_deadlock_account_unlock(current); -	else -		slowfn(lock); -} - -/** - * rt_mutex_lock - lock a rt_mutex - * - * @lock: the rt_mutex to be locked - */ -void __sched rt_mutex_lock(struct rt_mutex *lock) -{ -	might_sleep(); - -	rt_mutex_fastlock(lock, TASK_UNINTERRUPTIBLE, 0, rt_mutex_slowlock); -} -EXPORT_SYMBOL_GPL(rt_mutex_lock); - -/** - * rt_mutex_lock_interruptible - lock a rt_mutex interruptible - * - * @lock: 		the rt_mutex to be locked - * @detect_deadlock:	deadlock detection on/off - * - * Returns: - *  0 		on success - * -EINTR 	when interrupted by a signal - * -EDEADLK	when the lock would deadlock (when deadlock detection is on) - */ -int __sched rt_mutex_lock_interruptible(struct rt_mutex *lock, -						 int detect_deadlock) -{ -	might_sleep(); - -	return rt_mutex_fastlock(lock, TASK_INTERRUPTIBLE, -				 detect_deadlock, rt_mutex_slowlock); -} -EXPORT_SYMBOL_GPL(rt_mutex_lock_interruptible); - -/** - * rt_mutex_timed_lock - lock a rt_mutex interruptible - *			the timeout structure is provided - *			by the caller - * - * @lock: 		the rt_mutex to be locked - * @timeout:		timeout structure or NULL (no timeout) - * @detect_deadlock:	deadlock detection on/off - * - * Returns: - *  0 		on success - * -EINTR 	when interrupted by a signal - * -ETIMEDOUT	when the timeout expired - * -EDEADLK	when the lock would deadlock (when deadlock detection is on) - */ -int -rt_mutex_timed_lock(struct rt_mutex *lock, struct hrtimer_sleeper *timeout, -		    int detect_deadlock) -{ -	might_sleep(); - -	return rt_mutex_timed_fastlock(lock, TASK_INTERRUPTIBLE, timeout, -				       detect_deadlock, rt_mutex_slowlock); -} -EXPORT_SYMBOL_GPL(rt_mutex_timed_lock); - -/** - * rt_mutex_trylock - try to lock a rt_mutex - * - * @lock:	the rt_mutex to be locked - * - * Returns 1 on success and 0 on contention - */ -int __sched rt_mutex_trylock(struct rt_mutex *lock) -{ -	return rt_mutex_fasttrylock(lock, rt_mutex_slowtrylock); -} -EXPORT_SYMBOL_GPL(rt_mutex_trylock); - -/** - * rt_mutex_unlock - unlock a rt_mutex - * - * @lock: the rt_mutex to be unlocked - */ -void __sched rt_mutex_unlock(struct rt_mutex *lock) -{ -	rt_mutex_fastunlock(lock, rt_mutex_slowunlock); -} -EXPORT_SYMBOL_GPL(rt_mutex_unlock); - -/** - * rt_mutex_destroy - mark a mutex unusable - * @lock: the mutex to be destroyed - * - * This function marks the mutex uninitialized, and any subsequent - * use of the mutex is forbidden. The mutex must not be locked when - * this function is called. - */ -void rt_mutex_destroy(struct rt_mutex *lock) -{ -	WARN_ON(rt_mutex_is_locked(lock)); -#ifdef CONFIG_DEBUG_RT_MUTEXES -	lock->magic = NULL; -#endif -} - -EXPORT_SYMBOL_GPL(rt_mutex_destroy); - -/** - * __rt_mutex_init - initialize the rt lock - * - * @lock: the rt lock to be initialized - * - * Initialize the rt lock to unlocked state. - * - * Initializing of a locked rt lock is not allowed - */ -void __rt_mutex_init(struct rt_mutex *lock, const char *name) -{ -	lock->owner = NULL; -	raw_spin_lock_init(&lock->wait_lock); -	plist_head_init(&lock->wait_list); - -	debug_rt_mutex_init(lock, name); -} -EXPORT_SYMBOL_GPL(__rt_mutex_init); - -/** - * rt_mutex_init_proxy_locked - initialize and lock a rt_mutex on behalf of a - *				proxy owner - * - * @lock: 	the rt_mutex to be locked - * @proxy_owner:the task to set as owner - * - * No locking. Caller has to do serializing itself - * Special API call for PI-futex support - */ -void rt_mutex_init_proxy_locked(struct rt_mutex *lock, -				struct task_struct *proxy_owner) -{ -	__rt_mutex_init(lock, NULL); -	debug_rt_mutex_proxy_lock(lock, proxy_owner); -	rt_mutex_set_owner(lock, proxy_owner); -	rt_mutex_deadlock_account_lock(lock, proxy_owner); -} - -/** - * rt_mutex_proxy_unlock - release a lock on behalf of owner - * - * @lock: 	the rt_mutex to be locked - * - * No locking. Caller has to do serializing itself - * Special API call for PI-futex support - */ -void rt_mutex_proxy_unlock(struct rt_mutex *lock, -			   struct task_struct *proxy_owner) -{ -	debug_rt_mutex_proxy_unlock(lock); -	rt_mutex_set_owner(lock, NULL); -	rt_mutex_deadlock_account_unlock(proxy_owner); -} - -/** - * rt_mutex_start_proxy_lock() - Start lock acquisition for another task - * @lock:		the rt_mutex to take - * @waiter:		the pre-initialized rt_mutex_waiter - * @task:		the task to prepare - * @detect_deadlock:	perform deadlock detection (1) or not (0) - * - * Returns: - *  0 - task blocked on lock - *  1 - acquired the lock for task, caller should wake it up - * <0 - error - * - * Special API call for FUTEX_REQUEUE_PI support. - */ -int rt_mutex_start_proxy_lock(struct rt_mutex *lock, -			      struct rt_mutex_waiter *waiter, -			      struct task_struct *task, int detect_deadlock) -{ -	int ret; - -	raw_spin_lock(&lock->wait_lock); - -	if (try_to_take_rt_mutex(lock, task, NULL)) { -		raw_spin_unlock(&lock->wait_lock); -		return 1; -	} - -	ret = task_blocks_on_rt_mutex(lock, waiter, task, detect_deadlock); - -	if (ret && !rt_mutex_owner(lock)) { -		/* -		 * Reset the return value. We might have -		 * returned with -EDEADLK and the owner -		 * released the lock while we were walking the -		 * pi chain.  Let the waiter sort it out. -		 */ -		ret = 0; -	} - -	if (unlikely(ret)) -		remove_waiter(lock, waiter); - -	raw_spin_unlock(&lock->wait_lock); - -	debug_rt_mutex_print_deadlock(waiter); - -	return ret; -} - -/** - * rt_mutex_next_owner - return the next owner of the lock - * - * @lock: the rt lock query - * - * Returns the next owner of the lock or NULL - * - * Caller has to serialize against other accessors to the lock - * itself. - * - * Special API call for PI-futex support - */ -struct task_struct *rt_mutex_next_owner(struct rt_mutex *lock) -{ -	if (!rt_mutex_has_waiters(lock)) -		return NULL; - -	return rt_mutex_top_waiter(lock)->task; -} - -/** - * rt_mutex_finish_proxy_lock() - Complete lock acquisition - * @lock:		the rt_mutex we were woken on - * @to:			the timeout, null if none. hrtimer should already have - * 			been started. - * @waiter:		the pre-initialized rt_mutex_waiter - * @detect_deadlock:	perform deadlock detection (1) or not (0) - * - * Complete the lock acquisition started our behalf by another thread. - * - * Returns: - *  0 - success - * <0 - error, one of -EINTR, -ETIMEDOUT, or -EDEADLK - * - * Special API call for PI-futex requeue support - */ -int rt_mutex_finish_proxy_lock(struct rt_mutex *lock, -			       struct hrtimer_sleeper *to, -			       struct rt_mutex_waiter *waiter, -			       int detect_deadlock) -{ -	int ret; - -	raw_spin_lock(&lock->wait_lock); - -	set_current_state(TASK_INTERRUPTIBLE); - -	ret = __rt_mutex_slowlock(lock, TASK_INTERRUPTIBLE, to, waiter); - -	set_current_state(TASK_RUNNING); - -	if (unlikely(ret)) -		remove_waiter(lock, waiter); - -	/* -	 * try_to_take_rt_mutex() sets the waiter bit unconditionally. We might -	 * have to fix that up. -	 */ -	fixup_rt_mutex_waiters(lock); - -	raw_spin_unlock(&lock->wait_lock); - -	return ret; -}  | 
