Merge branch 'linus' into cont_syslog

[safe/jmp/linux-2.6] / include / linux / semaphore.h

diff --git a/include/linux/semaphore.h b/include/linux/semaphore.h
index 88f2a28..7415839 100644 (file)
--- a/include/linux/semaphore.h
+++ b/include/linux/semaphore.h
@@ -4,8 +4,7 @@
  *
  * Distributed under the terms of the GNU GPL, version 2
  *
- * Counting semaphores allow up to <n> tasks to acquire the semaphore
- * simultaneously.
+ * Please see kernel/semaphore.c for documentation of these functions
  */
 #ifndef __LINUX_SEMAPHORE_H
 #define __LINUX_SEMAPHORE_H
@@ -13,17 +12,10 @@
 #include <linux/list.h>
 #include <linux/spinlock.h>
 
-/*
- * The spinlock controls access to the other members of the semaphore.
- * 'count' is decremented by every task which calls down*() and incremented
- * by every call to up().  Thus, if it is positive, it indicates how many
- * more tasks may acquire the lock.  If it is negative, it indicates how
- * many tasks are waiting for the lock.  Tasks waiting for the lock are
- * kept on the wait_list.
- */
+/* Please don't access any members of this structure directly */
 struct semaphore {
        spinlock_t              lock;
-       int                     count;
+       unsigned int            count;
        struct list_head        wait_list;
 };
 
@@ -34,10 +26,8 @@ struct semaphore {
        .wait_list      = LIST_HEAD_INIT((name).wait_list),             \
 }
 
-#define __DECLARE_SEMAPHORE_GENERIC(name, count) \
-       struct semaphore name = __SEMAPHORE_INITIALIZER(name, count)
-
-#define DECLARE_MUTEX(name)    __DECLARE_SEMAPHORE_GENERIC(name, 1)
+#define DECLARE_MUTEX(name)    \
+       struct semaphore name = __SEMAPHORE_INITIALIZER(name, 1)
 
 static inline void sema_init(struct semaphore *sem, int val)
 {
@@ -49,35 +39,11 @@ static inline void sema_init(struct semaphore *sem, int val)
 #define init_MUTEX(sem)                sema_init(sem, 1)
 #define init_MUTEX_LOCKED(sem) sema_init(sem, 0)
 
-/*
- * Attempt to acquire the semaphore.  If another task is already holding the
- * semaphore, sleep until the semaphore is released.
- */
 extern void down(struct semaphore *sem);
-
-/*
- * As down(), except the sleep may be interrupted by a signal.  If it is,
- * this function will return -EINTR.
- */
 extern int __must_check down_interruptible(struct semaphore *sem);
-
-/*
- * As down_interruptible(), except the sleep may only be interrupted by
- * signals which are fatal to this process.
- */
 extern int __must_check down_killable(struct semaphore *sem);
-
-/*
- * As down(), except this function will not sleep.  It will return 0 if it
- * acquired the semaphore and 1 if the semaphore was contended.  This
- * function may be called from any context, including interrupt and softirq.
- */
 extern int __must_check down_trylock(struct semaphore *sem);
-
-/*
- * Release the semaphore.  Unlike mutexes, up() may be called from any
- * context and even by tasks which have never called down().
- */
+extern int __must_check down_timeout(struct semaphore *sem, long jiffies);
 extern void up(struct semaphore *sem);
 
 #endif /* __LINUX_SEMAPHORE_H */