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authorPeter Zijlstra <peterz@infradead.org>2013-10-31 18:18:19 +0100
committerIngo Molnar <mingo@kernel.org>2013-11-06 09:23:59 +0100
commit1696a8bee390929fed05c6297164816ae2ced280 (patch)
tree59866e14aa5f8bf6f5ac0fa69211be6a5e05afd3 /kernel/rtmutex.c
parente25a64c4017e3a3cda17454b040737e410a12991 (diff)
locking: Move the rtmutex code to kernel/locking/
Suggested-by: Ingo Molnar <mingo@kernel.org> Signed-off-by: Peter Zijlstra <peterz@infradead.org> Link: http://lkml.kernel.org/n/tip-p9ijt8div0hwldexwfm4nlhj@git.kernel.org [ Fixed build failure in kernel/rcu/tree_plugin.h. ] Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'kernel/rtmutex.c')
-rw-r--r--kernel/rtmutex.c1060
1 files changed, 0 insertions, 1060 deletions
diff --git a/kernel/rtmutex.c b/kernel/rtmutex.c
deleted file mode 100644
index 0dd6aec1cb6a..000000000000
--- 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(&current->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, &current->pi_waiters);
-
- rt_mutex_set_owner(lock, NULL);
-
- raw_spin_unlock_irqrestore(&current->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(&current->pi_lock, flags);
- plist_del(&waiter->list_entry, &lock->wait_list);
- current->pi_blocked_on = NULL;
- raw_spin_unlock_irqrestore(&current->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;
-}