* 2) Drop lock->wait_lock
* 3) Try to unlock the lock with cmpxchg
*/
-static inline bool unlock_rt_mutex_safe(struct rt_mutex *lock)
+static inline bool unlock_rt_mutex_safe(struct rt_mutex *lock,
+ unsigned long flags)
__releases(lock->wait_lock)
{
struct task_struct *owner = rt_mutex_owner(lock);
clear_rt_mutex_waiters(lock);
- raw_spin_unlock(&lock->wait_lock);
+ raw_spin_unlock_irqrestore(&lock->wait_lock, flags);
/*
* If a new waiter comes in between the unlock and the cmpxchg
* we have two situations:
/*
* Simple slow path only version: lock->owner is protected by lock->wait_lock.
*/
-static inline bool unlock_rt_mutex_safe(struct rt_mutex *lock)
+static inline bool unlock_rt_mutex_safe(struct rt_mutex *lock,
+ unsigned long flags)
__releases(lock->wait_lock)
{
lock->owner = NULL;
- raw_spin_unlock(&lock->wait_lock);
+ raw_spin_unlock_irqrestore(&lock->wait_lock, flags);
return true;
}
#endif
int ret = 0, depth = 0;
struct rt_mutex *lock;
bool detect_deadlock;
- unsigned long flags;
bool requeue = true;
detect_deadlock = rt_mutex_cond_detect_deadlock(orig_waiter, chwalk);
/*
* [1] Task cannot go away as we did a get_task() before !
*/
- raw_spin_lock_irqsave(&task->pi_lock, flags);
+ raw_spin_lock_irq(&task->pi_lock);
/*
* [2] Get the waiter on which @task is blocked on.
* operations.
*/
if (!raw_spin_trylock(&lock->wait_lock)) {
- raw_spin_unlock_irqrestore(&task->pi_lock, flags);
+ raw_spin_unlock_irq(&task->pi_lock);
cpu_relax();
goto retry;
}
/*
* No requeue[7] here. Just release @task [8]
*/
- raw_spin_unlock_irqrestore(&task->pi_lock, flags);
+ raw_spin_unlock(&task->pi_lock);
put_task_struct(task);
/*
* If there is no owner of the lock, end of chain.
*/
if (!rt_mutex_owner(lock)) {
- raw_spin_unlock(&lock->wait_lock);
+ raw_spin_unlock_irq(&lock->wait_lock);
return 0;
}
/* [10] Grab the next task, i.e. owner of @lock */
task = rt_mutex_owner(lock);
get_task_struct(task);
- raw_spin_lock_irqsave(&task->pi_lock, flags);
+ raw_spin_lock(&task->pi_lock);
/*
* No requeue [11] here. We just do deadlock detection.
top_waiter = rt_mutex_top_waiter(lock);
/* [13] Drop locks */
- raw_spin_unlock_irqrestore(&task->pi_lock, flags);
- raw_spin_unlock(&lock->wait_lock);
+ raw_spin_unlock(&task->pi_lock);
+ raw_spin_unlock_irq(&lock->wait_lock);
/* If owner is not blocked, end of chain. */
if (!next_lock)
rt_mutex_enqueue(lock, waiter);
/* [8] Release the task */
- raw_spin_unlock_irqrestore(&task->pi_lock, flags);
+ raw_spin_unlock(&task->pi_lock);
put_task_struct(task);
/*
*/
if (prerequeue_top_waiter != rt_mutex_top_waiter(lock))
wake_up_process(rt_mutex_top_waiter(lock)->task);
- raw_spin_unlock(&lock->wait_lock);
+ raw_spin_unlock_irq(&lock->wait_lock);
return 0;
}
/* [10] Grab the next task, i.e. the owner of @lock */
task = rt_mutex_owner(lock);
get_task_struct(task);
- raw_spin_lock_irqsave(&task->pi_lock, flags);
+ raw_spin_lock(&task->pi_lock);
/* [11] requeue the pi waiters if necessary */
if (waiter == rt_mutex_top_waiter(lock)) {
top_waiter = rt_mutex_top_waiter(lock);
/* [13] Drop the locks */
- raw_spin_unlock_irqrestore(&task->pi_lock, flags);
- raw_spin_unlock(&lock->wait_lock);
+ raw_spin_unlock(&task->pi_lock);
+ raw_spin_unlock_irq(&lock->wait_lock);
/*
* Make the actual exit decisions [12], based on the stored
goto again;
out_unlock_pi:
- raw_spin_unlock_irqrestore(&task->pi_lock, flags);
+ raw_spin_unlock_irq(&task->pi_lock);
out_put_task:
put_task_struct(task);
/*
* Try to take an rt-mutex
*
- * Must be called with lock->wait_lock held.
+ * Must be called with lock->wait_lock held and interrupts disabled
*
* @lock: The lock to be acquired.
* @task: The task which wants to acquire the lock
static int try_to_take_rt_mutex(struct rt_mutex *lock, struct task_struct *task,
struct rt_mutex_waiter *waiter)
{
- unsigned long flags;
-
/*
* Before testing whether we can acquire @lock, we set the
* RT_MUTEX_HAS_WAITERS bit in @lock->owner. This forces all
* case, but conditionals are more expensive than a redundant
* store.
*/
- raw_spin_lock_irqsave(&task->pi_lock, flags);
+ raw_spin_lock(&task->pi_lock);
task->pi_blocked_on = NULL;
/*
* Finish the lock acquisition. @task is the new owner. If
*/
if (rt_mutex_has_waiters(lock))
rt_mutex_enqueue_pi(task, rt_mutex_top_waiter(lock));
- raw_spin_unlock_irqrestore(&task->pi_lock, flags);
+ raw_spin_unlock(&task->pi_lock);
takeit:
/* We got the lock. */
*
* Prepare waiter and propagate pi chain
*
- * This must be called with lock->wait_lock held.
+ * This must be called with lock->wait_lock held and interrupts disabled
*/
static int task_blocks_on_rt_mutex(struct rt_mutex *lock,
struct rt_mutex_waiter *waiter,
struct rt_mutex_waiter *top_waiter = waiter;
struct rt_mutex *next_lock;
int chain_walk = 0, res;
- unsigned long flags;
/*
* Early deadlock detection. We really don't want the task to
if (owner == task)
return -EDEADLK;
- raw_spin_lock_irqsave(&task->pi_lock, flags);
+ raw_spin_lock(&task->pi_lock);
__rt_mutex_adjust_prio(task);
waiter->task = task;
waiter->lock = lock;
task->pi_blocked_on = waiter;
- raw_spin_unlock_irqrestore(&task->pi_lock, flags);
+ raw_spin_unlock(&task->pi_lock);
if (!owner)
return 0;
- raw_spin_lock_irqsave(&owner->pi_lock, flags);
+ raw_spin_lock(&owner->pi_lock);
if (waiter == rt_mutex_top_waiter(lock)) {
rt_mutex_dequeue_pi(owner, top_waiter);
rt_mutex_enqueue_pi(owner, waiter);
/* Store the lock on which owner is blocked or NULL */
next_lock = task_blocked_on_lock(owner);
- raw_spin_unlock_irqrestore(&owner->pi_lock, flags);
+ raw_spin_unlock(&owner->pi_lock);
/*
* Even if full deadlock detection is on, if the owner is not
* blocked itself, we can avoid finding this out in the chain
*/
get_task_struct(owner);
- raw_spin_unlock(&lock->wait_lock);
+ raw_spin_unlock_irq(&lock->wait_lock);
res = rt_mutex_adjust_prio_chain(owner, chwalk, lock,
next_lock, waiter, task);
- raw_spin_lock(&lock->wait_lock);
+ raw_spin_lock_irq(&lock->wait_lock);
return res;
}
* Remove the top waiter from the current tasks pi waiter tree and
* queue it up.
*
- * Called with lock->wait_lock held.
+ * Called with lock->wait_lock held and interrupts disabled.
*/
static void mark_wakeup_next_waiter(struct wake_q_head *wake_q,
struct rt_mutex *lock)
{
struct rt_mutex_waiter *waiter;
- unsigned long flags;
- raw_spin_lock_irqsave(¤t->pi_lock, flags);
+ raw_spin_lock(¤t->pi_lock);
waiter = rt_mutex_top_waiter(lock);
*/
lock->owner = (void *) RT_MUTEX_HAS_WAITERS;
- raw_spin_unlock_irqrestore(¤t->pi_lock, flags);
+ raw_spin_unlock(¤t->pi_lock);
wake_q_add(wake_q, waiter->task);
}
/*
* Remove a waiter from a lock and give up
*
- * Must be called with lock->wait_lock held and
+ * Must be called with lock->wait_lock held and interrupts disabled. I must
* have just failed to try_to_take_rt_mutex().
*/
static void remove_waiter(struct rt_mutex *lock,
bool is_top_waiter = (waiter == rt_mutex_top_waiter(lock));
struct task_struct *owner = rt_mutex_owner(lock);
struct rt_mutex *next_lock;
- unsigned long flags;
- raw_spin_lock_irqsave(¤t->pi_lock, flags);
+ raw_spin_lock(¤t->pi_lock);
rt_mutex_dequeue(lock, waiter);
current->pi_blocked_on = NULL;
- raw_spin_unlock_irqrestore(¤t->pi_lock, flags);
+ raw_spin_unlock(¤t->pi_lock);
/*
* Only update priority if the waiter was the highest priority
if (!owner || !is_top_waiter)
return;
- raw_spin_lock_irqsave(&owner->pi_lock, flags);
+ raw_spin_lock(&owner->pi_lock);
rt_mutex_dequeue_pi(owner, waiter);
/* Store the lock on which owner is blocked or NULL */
next_lock = task_blocked_on_lock(owner);
- raw_spin_unlock_irqrestore(&owner->pi_lock, flags);
+ raw_spin_unlock(&owner->pi_lock);
/*
* Don't walk the chain, if the owner task is not blocked
/* gets dropped in rt_mutex_adjust_prio_chain()! */
get_task_struct(owner);
- raw_spin_unlock(&lock->wait_lock);
+ raw_spin_unlock_irq(&lock->wait_lock);
rt_mutex_adjust_prio_chain(owner, RT_MUTEX_MIN_CHAINWALK, lock,
next_lock, NULL, current);
- raw_spin_lock(&lock->wait_lock);
+ raw_spin_lock_irq(&lock->wait_lock);
}
/*
* __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)
+ * 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.
+ * Must be called with lock->wait_lock held and interrupts disabled
*/
static int __sched
__rt_mutex_slowlock(struct rt_mutex *lock, int state,
break;
}
- raw_spin_unlock(&lock->wait_lock);
+ raw_spin_unlock_irq(&lock->wait_lock);
debug_rt_mutex_print_deadlock(waiter);
schedule();
- raw_spin_lock(&lock->wait_lock);
+ raw_spin_lock_irq(&lock->wait_lock);
set_current_state(state);
}
enum rtmutex_chainwalk chwalk)
{
struct rt_mutex_waiter waiter;
+ unsigned long flags;
int ret = 0;
debug_rt_mutex_init_waiter(&waiter);
RB_CLEAR_NODE(&waiter.pi_tree_entry);
RB_CLEAR_NODE(&waiter.tree_entry);
- raw_spin_lock(&lock->wait_lock);
+ /*
+ * Technically we could use raw_spin_[un]lock_irq() here, but this can
+ * be called in early boot if the cmpxchg() fast path is disabled
+ * (debug, no architecture support). In this case we will acquire the
+ * rtmutex with lock->wait_lock held. But we cannot unconditionally
+ * enable interrupts in that early boot case. So we need to use the
+ * irqsave/restore variants.
+ */
+ raw_spin_lock_irqsave(&lock->wait_lock, flags);
/* Try to acquire the lock again: */
if (try_to_take_rt_mutex(lock, current, NULL)) {
- raw_spin_unlock(&lock->wait_lock);
+ raw_spin_unlock_irqrestore(&lock->wait_lock, flags);
return 0;
}
*/
fixup_rt_mutex_waiters(lock);
- raw_spin_unlock(&lock->wait_lock);
+ raw_spin_unlock_irqrestore(&lock->wait_lock, flags);
/* Remove pending timer: */
if (unlikely(timeout))
*/
static inline int rt_mutex_slowtrylock(struct rt_mutex *lock)
{
+ unsigned long flags;
int ret;
/*
return 0;
/*
- * The mutex has currently no owner. Lock the wait lock and
- * try to acquire the lock.
+ * The mutex has currently no owner. Lock the wait lock and try to
+ * acquire the lock. We use irqsave here to support early boot calls.
*/
- raw_spin_lock(&lock->wait_lock);
+ raw_spin_lock_irqsave(&lock->wait_lock, flags);
ret = try_to_take_rt_mutex(lock, current, NULL);
*/
fixup_rt_mutex_waiters(lock);
- raw_spin_unlock(&lock->wait_lock);
+ raw_spin_unlock_irqrestore(&lock->wait_lock, flags);
return ret;
}
static bool __sched rt_mutex_slowunlock(struct rt_mutex *lock,
struct wake_q_head *wake_q)
{
- raw_spin_lock(&lock->wait_lock);
+ unsigned long flags;
+
+ /* irqsave required to support early boot calls */
+ raw_spin_lock_irqsave(&lock->wait_lock, flags);
debug_rt_mutex_unlock(lock);
*/
while (!rt_mutex_has_waiters(lock)) {
/* Drops lock->wait_lock ! */
- if (unlock_rt_mutex_safe(lock) == true)
+ if (unlock_rt_mutex_safe(lock, flags) == true)
return false;
/* Relock the rtmutex and try again */
- raw_spin_lock(&lock->wait_lock);
+ raw_spin_lock_irqsave(&lock->wait_lock, flags);
}
/*
*/
mark_wakeup_next_waiter(wake_q, lock);
- raw_spin_unlock(&lock->wait_lock);
+ raw_spin_unlock_irqrestore(&lock->wait_lock, flags);
/* check PI boosting */
return true;
{
int ret;
- raw_spin_lock(&lock->wait_lock);
+ raw_spin_lock_irq(&lock->wait_lock);
if (try_to_take_rt_mutex(lock, task, NULL)) {
- raw_spin_unlock(&lock->wait_lock);
+ raw_spin_unlock_irq(&lock->wait_lock);
return 1;
}
if (unlikely(ret))
remove_waiter(lock, waiter);
- raw_spin_unlock(&lock->wait_lock);
+ raw_spin_unlock_irq(&lock->wait_lock);
debug_rt_mutex_print_deadlock(waiter);
{
int ret;
- raw_spin_lock(&lock->wait_lock);
+ raw_spin_lock_irq(&lock->wait_lock);
set_current_state(TASK_INTERRUPTIBLE);
*/
fixup_rt_mutex_waiters(lock);
- raw_spin_unlock(&lock->wait_lock);
+ raw_spin_unlock_irq(&lock->wait_lock);
return ret;
}
projects / cascardo / linux.git / blobdiff