* 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/module.h>
* Decreases task's usage by one - may thus free the task.
* Returns 0 or -EDEADLK.
*/
-static int rt_mutex_adjust_prio_chain(task_t *task,
+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
- __IP_DECL__)
+ struct task_struct *top_task)
{
struct rt_mutex *lock;
struct rt_mutex_waiter *waiter, *top_waiter = orig_waiter;
/* Grab the next task */
task = rt_mutex_owner(lock);
+ get_task_struct(task);
spin_lock_irqsave(&task->pi_lock, flags);
if (waiter == rt_mutex_top_waiter(lock)) {
__rt_mutex_adjust_prio(task);
}
- get_task_struct(task);
spin_unlock_irqrestore(&task->pi_lock, flags);
top_waiter = rt_mutex_top_waiter(lock);
spin_unlock_irqrestore(&task->pi_lock, flags);
out_put_task:
put_task_struct(task);
+
return ret;
}
*
* Must be called with lock->wait_lock held.
*/
-static int try_to_take_rt_mutex(struct rt_mutex *lock __IP_DECL__)
+static int try_to_take_rt_mutex(struct rt_mutex *lock)
{
/*
* We have to be careful here if the atomic speedups are
return 0;
/* We got the lock. */
- debug_rt_mutex_lock(lock __IP__);
+ debug_rt_mutex_lock(lock);
rt_mutex_set_owner(lock, current, 0);
*/
static int task_blocks_on_rt_mutex(struct rt_mutex *lock,
struct rt_mutex_waiter *waiter,
- int detect_deadlock
- __IP_DECL__)
+ int detect_deadlock)
{
+ struct task_struct *owner = rt_mutex_owner(lock);
struct rt_mutex_waiter *top_waiter = waiter;
- task_t *owner = rt_mutex_owner(lock);
- int boost = 0, res;
unsigned long flags;
+ int chain_walk = 0, res;
spin_lock_irqsave(¤t->pi_lock, flags);
__rt_mutex_adjust_prio(current);
plist_add(&waiter->pi_list_entry, &owner->pi_waiters);
__rt_mutex_adjust_prio(owner);
- if (owner->pi_blocked_on) {
- boost = 1;
- /* gets dropped in rt_mutex_adjust_prio_chain()! */
- get_task_struct(owner);
- }
+ if (owner->pi_blocked_on)
+ chain_walk = 1;
spin_unlock_irqrestore(&owner->pi_lock, flags);
}
- else if (debug_rt_mutex_detect_deadlock(waiter, detect_deadlock)) {
- spin_lock_irqsave(&owner->pi_lock, flags);
- if (owner->pi_blocked_on) {
- boost = 1;
- /* gets dropped in rt_mutex_adjust_prio_chain()! */
- get_task_struct(owner);
- }
- spin_unlock_irqrestore(&owner->pi_lock, flags);
- }
- if (!boost)
+ 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);
+
spin_unlock(&lock->wait_lock);
res = rt_mutex_adjust_prio_chain(owner, detect_deadlock, lock, waiter,
- current __IP__);
+ current);
spin_lock(&lock->wait_lock);
* Must be called with lock->wait_lock held
*/
static void remove_waiter(struct rt_mutex *lock,
- struct rt_mutex_waiter *waiter __IP_DECL__)
+ struct rt_mutex_waiter *waiter)
{
int first = (waiter == rt_mutex_top_waiter(lock));
- int boost = 0;
- task_t *owner = rt_mutex_owner(lock);
+ struct task_struct *owner = rt_mutex_owner(lock);
unsigned long flags;
+ int chain_walk = 0;
spin_lock_irqsave(¤t->pi_lock, flags);
plist_del(&waiter->list_entry, &lock->wait_list);
}
__rt_mutex_adjust_prio(owner);
- if (owner->pi_blocked_on) {
- boost = 1;
- /* gets dropped in rt_mutex_adjust_prio_chain()! */
- get_task_struct(owner);
- }
+ if (owner->pi_blocked_on)
+ chain_walk = 1;
+
spin_unlock_irqrestore(&owner->pi_lock, flags);
}
WARN_ON(!plist_node_empty(&waiter->pi_list_entry));
- if (!boost)
+ if (!chain_walk)
return;
+ /* gets dropped in rt_mutex_adjust_prio_chain()! */
+ get_task_struct(owner);
+
spin_unlock(&lock->wait_lock);
- rt_mutex_adjust_prio_chain(owner, 0, lock, NULL, current __IP__);
+ rt_mutex_adjust_prio_chain(owner, 0, lock, NULL, current);
spin_lock(&lock->wait_lock);
}
return;
}
- /* gets dropped in rt_mutex_adjust_prio_chain()! */
- get_task_struct(task);
spin_unlock_irqrestore(&task->pi_lock, flags);
- rt_mutex_adjust_prio_chain(task, 0, NULL, NULL, task __RET_IP__);
+ /* gets dropped in rt_mutex_adjust_prio_chain()! */
+ get_task_struct(task);
+ rt_mutex_adjust_prio_chain(task, 0, NULL, NULL, task);
}
/*
static int __sched
rt_mutex_slowlock(struct rt_mutex *lock, int state,
struct hrtimer_sleeper *timeout,
- int detect_deadlock __IP_DECL__)
+ int detect_deadlock)
{
struct rt_mutex_waiter waiter;
int ret = 0;
spin_lock(&lock->wait_lock);
/* Try to acquire the lock again: */
- if (try_to_take_rt_mutex(lock __IP__)) {
+ if (try_to_take_rt_mutex(lock)) {
spin_unlock(&lock->wait_lock);
return 0;
}
for (;;) {
/* Try to acquire the lock: */
- if (try_to_take_rt_mutex(lock __IP__))
+ if (try_to_take_rt_mutex(lock))
break;
/*
*/
if (!waiter.task) {
ret = task_blocks_on_rt_mutex(lock, &waiter,
- detect_deadlock __IP__);
+ detect_deadlock);
/*
* If we got woken up by the owner then start loop
* all over without going into schedule to try
set_current_state(TASK_RUNNING);
if (unlikely(waiter.task))
- remove_waiter(lock, &waiter __IP__);
+ remove_waiter(lock, &waiter);
/*
* try_to_take_rt_mutex() sets the waiter bit
* Slow path try-lock function:
*/
static inline int
-rt_mutex_slowtrylock(struct rt_mutex *lock __IP_DECL__)
+rt_mutex_slowtrylock(struct rt_mutex *lock)
{
int ret = 0;
if (likely(rt_mutex_owner(lock) != current)) {
- ret = try_to_take_rt_mutex(lock __IP__);
+ ret = try_to_take_rt_mutex(lock);
/*
* try_to_take_rt_mutex() sets the lock waiters
* bit unconditionally. Clean this up.
int detect_deadlock,
int (*slowfn)(struct rt_mutex *lock, int state,
struct hrtimer_sleeper *timeout,
- int detect_deadlock __IP_DECL__))
+ 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 __RET_IP__);
+ return slowfn(lock, state, NULL, detect_deadlock);
}
static inline int
struct hrtimer_sleeper *timeout, int detect_deadlock,
int (*slowfn)(struct rt_mutex *lock, int state,
struct hrtimer_sleeper *timeout,
- int detect_deadlock __IP_DECL__))
+ 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 __RET_IP__);
+ return slowfn(lock, state, timeout, detect_deadlock);
}
static inline int
rt_mutex_fasttrylock(struct rt_mutex *lock,
- int (*slowfn)(struct rt_mutex *lock __IP_DECL__))
+ 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 __RET_IP__);
+ return slowfn(lock);
}
static inline void
struct task_struct *proxy_owner)
{
__rt_mutex_init(lock, NULL);
- debug_rt_mutex_proxy_lock(lock, proxy_owner __RET_IP__);
+ debug_rt_mutex_proxy_lock(lock, proxy_owner);
rt_mutex_set_owner(lock, proxy_owner, 0);
rt_mutex_deadlock_account_lock(lock, proxy_owner);
}
git.openpandora.org / pandora-kernel.git / blobdiff