patch-2.3.45 linux/include/asm-arm/semaphore.h

• Lines: 255
• Date: Sun Feb 13 10:47:01 2000
• Orig file: v2.3.44/linux/include/asm-arm/semaphore.h
• Orig date: Fri Oct 22 13:21:53 1999

diff -u --recursive --new-file v2.3.44/linux/include/asm-arm/semaphore.h linux/include/asm-arm/semaphore.h
@@ -9,16 +9,28 @@
 #include <linux/wait.h>
 
 #include <asm/atomic.h>
+#include <asm/proc/locks.h>
 
 struct semaphore {
 	atomic_t count;
 	int sleepers;
 	wait_queue_head_t wait;
+#if WAITQUEUE_DEBUG
+	long __magic;
+#endif
 };
 
+#if WAITQUEUE_DEBUG
+# define __SEM_DEBUG_INIT(name) \
+		, (long)&(name).__magic
+#else
+# define __SEM_DEBUG_INIT(name)
+#endif
+
 #define __SEMAPHORE_INIT(name,count)			\
 	{ ATOMIC_INIT(count), 0,			\
-	  __WAIT_QUEUE_HEAD_INITIALIZER((name).wait) }
+	  __WAIT_QUEUE_HEAD_INITIALIZER((name).wait)	\
+	  __SEM_DEBUG_INIT(name) }
 
 #define __MUTEX_INITIALIZER(name) \
 	__SEMAPHORE_INIT(name,1)
@@ -29,12 +41,15 @@
 #define DECLARE_MUTEX(name)		__DECLARE_SEMAPHORE_GENERIC(name,1)
 #define DECLARE_MUTEX_LOCKED(name)	__DECLARE_SEMAPHORE_GENERIC(name,0)
 
-#define sema_init(sem, val)			\
-do {						\
-	atomic_set(&((sem)->count), (val));	\
-	(sem)->sleepers = 0;			\
-	init_waitqueue_head(&(sem)->wait);	\
-} while (0)
+extern inline void sema_init(struct semaphore *sem, int val)
+{
+	atomic_set(&sem->count, val);
+	sem->sleepers = 0;
+	init_waitqueue_head(&sem->wait);
+#if WAITQUEUE_DEBUG
+	sem->__magic = (long)&sem->__magic;
+#endif
+}
 
 static inline void init_MUTEX(struct semaphore *sem)
 {
@@ -46,18 +61,196 @@
 	sema_init(sem, 0);
 }
 
-asmlinkage void __down_failed (void /* special register calling convention */);
-asmlinkage int  __down_interruptible_failed (void /* special register calling convention */);
-asmlinkage int  __down_trylock_failed(void  /* params in registers */);
-asmlinkage void __up_wakeup (void /* special register calling convention */);
+/*
+ * special register calling convention
+ */
+asmlinkage void __down_failed(void);
+asmlinkage int  __down_interruptible_failed(void);
+asmlinkage int  __down_trylock_failed(void);
+asmlinkage void __up_wakeup(void);
 
 extern void __down(struct semaphore * sem);
 extern int  __down_interruptible(struct semaphore * sem);
 extern int  __down_trylock(struct semaphore * sem);
 extern void __up(struct semaphore * sem);
 
-extern spinlock_t semaphore_wake_lock;
+/*
+ * This is ugly, but we want the default case to fall through.
+ * "__down" is the actual routine that waits...
+ */
+extern inline void down(struct semaphore * sem)
+{
+#if WAITQUEUE_DEBUG
+	CHECK_MAGIC(sem->__magic);
+#endif
+
+	__down_op(sem, __down_failed);
+}
+
+/*
+ * This is ugly, but we want the default case to fall through.
+ * "__down_interruptible" is the actual routine that waits...
+ */
+extern inline int down_interruptible (struct semaphore * sem)
+{
+#if WAITQUEUE_DEBUG
+	CHECK_MAGIC(sem->__magic);
+#endif
+
+	return __down_op_ret(sem, __down_interruptible_failed);
+}
+
+extern inline int down_trylock(struct semaphore *sem)
+{
+#if WAITQUEUE_DEBUG
+	CHECK_MAGIC(sem->__magic);
+#endif
+
+	return __down_op_ret(sem, __down_trylock_failed);
+}
+
+/*
+ * Note! This is subtle. We jump to wake people up only if
+ * the semaphore was negative (== somebody was waiting on it).
+ * The default case (no contention) will result in NO
+ * jumps for both down() and up().
+ */
+extern inline void up(struct semaphore * sem)
+{
+#if WAITQUEUE_DEBUG
+	CHECK_MAGIC(sem->__magic);
+#endif
+
+	__up_op(sem, __up_wakeup);
+}
+
+/* rw mutexes (should that be mutices? =) -- throw rw
+ * spinlocks and semaphores together, and this is what we
+ * end up with...
+ *
+ * The lock is initialized to BIAS.  This way, a writer
+ * subtracts BIAS ands gets 0 for the case of an uncontended
+ * lock.  Readers decrement by 1 and see a positive value
+ * when uncontended, negative if there are writers waiting
+ * (in which case it goes to sleep).
+ *
+ * In terms of fairness, this should result in the lock
+ * flopping back and forth between readers and writers
+ * under heavy use.
+ *
+ *              -ben
+ */
+struct rw_semaphore {
+	atomic_t                count;
+	volatile unsigned char  write_bias_granted;
+	volatile unsigned char  read_bias_granted;
+	volatile unsigned char  pad1;
+	volatile unsigned char  pad2;
+	wait_queue_head_t       wait;
+	wait_queue_head_t	write_bias_wait;
+#if WAITQUEUE_DEBUG
+	long			__magic;
+	atomic_t		readers;
+	atomic_t		writers;
+#endif
+};
+
+#if WAITQUEUE_DEBUG
+#define __RWSEM_DEBUG_INIT	, ATOMIC_INIT(0), ATOMIC_INIT(0)
+#else
+#define __RWSEM_DEBUG_INIT	/* */
+#endif
+
+#define __RWSEM_INITIALIZER(name,count) \
+{ ATOMIC_INIT(count), 0, 0, 0, 0, __WAIT_QUEUE_HEAD_INITIALIZER((name).wait), \
+	__WAIT_QUEUE_HEAD_INITIALIZER((name).write_bias_wait) \
+	__SEM_DEBUG_INIT(name) __RWSEM_DEBUG_INIT }
+
+#define __DECLARE_RWSEM_GENERIC(name,count) \
+	struct rw_semaphore name = __RWSEM_INITIALIZER(name,count)
+
+#define DECLARE_RWSEM(name) __DECLARE_RWSEM_GENERIC(name,RW_LOCK_BIAS)
+#define DECLARE_RWSEM_READ_LOCKED(name) __DECLARE_RWSEM_GENERIC(name,RW_LOCK_BIAS-1)
+#define DECLARE_RWSEM_WRITE_LOCKED(name) __DECLARE_RWSEM_GENERIC(name,0)
+
+extern inline void init_rwsem(struct rw_semaphore *sem)
+{
+	atomic_set(&sem->count, RW_LOCK_BIAS);
+	sem->read_bias_granted = 0;
+	sem->write_bias_granted = 0;
+	init_waitqueue_head(&sem->wait);
+	init_waitqueue_head(&sem->write_bias_wait);
+#if WAITQUEUE_DEBUG
+	sem->__magic = (long)&sem->__magic;
+	atomic_set(&sem->readers, 0);
+	atomic_set(&sem->writers, 0);
+#endif
+}
+
+extern struct rw_semaphore *__down_read_failed(struct rw_semaphore *sem);
+extern struct rw_semaphore *__down_write_failed(struct rw_semaphore *sem);
+extern struct rw_semaphore *__rwsem_wake(struct rw_semaphore *sem);
+
+extern inline void down_read(struct rw_semaphore *sem)
+{
+#if WAITQUEUE_DEBUG
+	CHECK_MAGIC(sem->__magic);
+#endif
+	__down_op_read(sem, __down_read_failed);
+#if WAITQUEUE_DEBUG
+	if (sem->write_bias_granted)
+		BUG();
+	if (atomic_read(&sem->writers))
+		BUG();
+	atomic_inc(&sem->readers);
+#endif
+}
+
+extern inline void down_write(struct rw_semaphore *sem)
+{
+#if WAITQUEUE_DEBUG
+	CHECK_MAGIC(sem->__magic);
+#endif
+	__down_op_write(sem, __down_write_failed);
+#if WAITQUEUE_DEBUG
+	if (atomic_read(&sem->writers))
+		BUG();
+	if (atomic_read(&sem->readers))
+		BUG();
+	if (sem->read_bias_granted)
+		BUG();
+	if (sem->write_bias_granted)
+		BUG();
+	atomic_inc(&sem->writers);
+#endif
+}
 
-#include <asm/proc/semaphore.h>
+extern inline void up_read(struct rw_semaphore *sem)
+{
+#if WAITQUEUE_DEBUG
+	if (sem->write_bias_granted)
+		BUG();
+	if (atomic_read(&sem->writers))
+		BUG();
+	atomic_dec(&sem->readers);
+#endif
+	__up_op_read(sem, __rwsem_wake);
+}
+
+extern inline void up_write(struct rw_semaphore *sem)
+{
+#if WAITQUEUE_DEBUG
+	if (sem->read_bias_granted)
+		BUG();
+	if (sem->write_bias_granted)
+		BUG();
+	if (atomic_read(&sem->readers))
+		BUG();
+	if (atomic_read(&sem->writers) != 1)
+		BUG();
+	atomic_dec(&sem->writers);
+#endif
+	__up_op_write(sem, __rwsem_wake);
+}
 
 #endif