*/
#include <linux/mutex.h>
#include <linux/sched.h>
-#include <linux/module.h>
+#include <linux/export.h>
#include <linux/spinlock.h>
#include <linux/interrupt.h>
#include <linux/debug_locks.h>
# include <asm/mutex.h>
#endif
-/***
- * mutex_init - initialize the mutex
- * @lock: the mutex to be initialized
- * @key: the lock_class_key for the class; used by mutex lock debugging
- *
- * Initialize the mutex to unlocked state.
- *
- * It is not allowed to initialize an already locked mutex.
- */
void
__mutex_init(struct mutex *lock, const char *name, struct lock_class_key *key)
{
static __used noinline void __sched
__mutex_lock_slowpath(atomic_t *lock_count);
-/***
+/**
* mutex_lock - acquire the mutex
* @lock: the mutex to be acquired
*
*
* This function is similar to (but not equivalent to) down().
*/
-void inline __sched mutex_lock(struct mutex *lock)
+void __sched mutex_lock(struct mutex *lock)
{
might_sleep();
/*
static __used noinline void __sched __mutex_unlock_slowpath(atomic_t *lock_count);
-/***
+/**
* mutex_unlock - release the mutex
* @lock: the mutex to be released
*
*/
static inline int __sched
__mutex_lock_common(struct mutex *lock, long state, unsigned int subclass,
- unsigned long ip)
+ struct lockdep_map *nest_lock, unsigned long ip)
{
struct task_struct *task = current;
struct mutex_waiter waiter;
unsigned long flags;
preempt_disable();
- mutex_acquire(&lock->dep_map, subclass, 0, ip);
-#if defined(CONFIG_SMP) && !defined(CONFIG_DEBUG_MUTEXES) && \
- !defined(CONFIG_HAVE_DEFAULT_NO_SPIN_MUTEXES)
+ mutex_acquire_nest(&lock->dep_map, subclass, 0, nest_lock, ip);
+
+#ifdef CONFIG_MUTEX_SPIN_ON_OWNER
/*
* Optimistic spinning.
*
*/
for (;;) {
- struct thread_info *owner;
+ struct task_struct *owner;
/*
* If there's an owner, wait for it to either
* memory barriers as we'll eventually observe the right
* values at the cost of a few extra spins.
*/
- cpu_relax();
+ arch_mutex_cpu_relax();
}
#endif
spin_lock_mutex(&lock->wait_lock, flags);
}
__set_task_state(task, state);
- /* didnt get the lock, go to sleep: */
+ /* didn't get the lock, go to sleep: */
spin_unlock_mutex(&lock->wait_lock, flags);
- preempt_enable_no_resched();
- schedule();
- preempt_disable();
+ schedule_preempt_disabled();
spin_lock_mutex(&lock->wait_lock, flags);
}
mutex_lock_nested(struct mutex *lock, unsigned int subclass)
{
might_sleep();
- __mutex_lock_common(lock, TASK_UNINTERRUPTIBLE, subclass, _RET_IP_);
+ __mutex_lock_common(lock, TASK_UNINTERRUPTIBLE, subclass, NULL, _RET_IP_);
}
EXPORT_SYMBOL_GPL(mutex_lock_nested);
+void __sched
+_mutex_lock_nest_lock(struct mutex *lock, struct lockdep_map *nest)
+{
+ might_sleep();
+ __mutex_lock_common(lock, TASK_UNINTERRUPTIBLE, 0, nest, _RET_IP_);
+}
+
+EXPORT_SYMBOL_GPL(_mutex_lock_nest_lock);
+
int __sched
mutex_lock_killable_nested(struct mutex *lock, unsigned int subclass)
{
might_sleep();
- return __mutex_lock_common(lock, TASK_KILLABLE, subclass, _RET_IP_);
+ return __mutex_lock_common(lock, TASK_KILLABLE, subclass, NULL, _RET_IP_);
}
EXPORT_SYMBOL_GPL(mutex_lock_killable_nested);
{
might_sleep();
return __mutex_lock_common(lock, TASK_INTERRUPTIBLE,
- subclass, _RET_IP_);
+ subclass, NULL, _RET_IP_);
}
EXPORT_SYMBOL_GPL(mutex_lock_interruptible_nested);
static noinline int __sched
__mutex_lock_interruptible_slowpath(atomic_t *lock_count);
-/***
- * mutex_lock_interruptible - acquire the mutex, interruptable
+/**
+ * mutex_lock_interruptible - acquire the mutex, interruptible
* @lock: the mutex to be acquired
*
* Lock the mutex like mutex_lock(), and return 0 if the mutex has
{
struct mutex *lock = container_of(lock_count, struct mutex, count);
- __mutex_lock_common(lock, TASK_UNINTERRUPTIBLE, 0, _RET_IP_);
+ __mutex_lock_common(lock, TASK_UNINTERRUPTIBLE, 0, NULL, _RET_IP_);
}
static noinline int __sched
{
struct mutex *lock = container_of(lock_count, struct mutex, count);
- return __mutex_lock_common(lock, TASK_KILLABLE, 0, _RET_IP_);
+ return __mutex_lock_common(lock, TASK_KILLABLE, 0, NULL, _RET_IP_);
}
static noinline int __sched
{
struct mutex *lock = container_of(lock_count, struct mutex, count);
- return __mutex_lock_common(lock, TASK_INTERRUPTIBLE, 0, _RET_IP_);
+ return __mutex_lock_common(lock, TASK_INTERRUPTIBLE, 0, NULL, _RET_IP_);
}
#endif
return prev == 1;
}
-/***
- * mutex_trylock - try acquire the mutex, without waiting
+/**
+ * mutex_trylock - try to acquire the mutex, without waiting
* @lock: the mutex to be acquired
*
* Try to acquire the mutex atomically. Returns 1 if the mutex
* has been acquired successfully, and 0 on contention.
*
* NOTE: this function follows the spin_trylock() convention, so
- * it is negated to the down_trylock() return values! Be careful
+ * it is negated from the down_trylock() return values! Be careful
* about this when converting semaphore users to mutexes.
*
* This function must not be used in interrupt context. The
return ret;
}
-
EXPORT_SYMBOL(mutex_trylock);
+
+/**
+ * atomic_dec_and_mutex_lock - return holding mutex if we dec to 0
+ * @cnt: the atomic which we are to dec
+ * @lock: the mutex to return holding if we dec to 0
+ *
+ * return true and hold lock if we dec to 0, return false otherwise
+ */
+int atomic_dec_and_mutex_lock(atomic_t *cnt, struct mutex *lock)
+{
+ /* dec if we can't possibly hit 0 */
+ if (atomic_add_unless(cnt, -1, 1))
+ return 0;
+ /* we might hit 0, so take the lock */
+ mutex_lock(lock);
+ if (!atomic_dec_and_test(cnt)) {
+ /* when we actually did the dec, we didn't hit 0 */
+ mutex_unlock(lock);
+ return 0;
+ }
+ /* we hit 0, and we hold the lock */
+ return 1;
+}
+EXPORT_SYMBOL(atomic_dec_and_mutex_lock);
projects / linux-flexiantxendom0-3.2.10.git / blobdiff