patch-2.4.4 linux/include/asm-alpha/semaphore.h

• Lines: 165
• Date: Sun Apr 22 19:10:53 2001
• Orig file: v2.4.3/linux/include/asm-alpha/semaphore.h
• Orig date: Fri Mar 2 11:12:07 2001

diff -u --recursive --new-file v2.4.3/linux/include/asm-alpha/semaphore.h linux/include/asm-alpha/semaphore.h
@@ -11,8 +11,9 @@
 #include <asm/current.h>
 #include <asm/system.h>
 #include <asm/atomic.h>
-#include <asm/compiler.h>	/* __builtin_expect */
+#include <linux/compiler.h>
 #include <linux/wait.h>
+#include <linux/rwsem.h>
 
 #define DEBUG_SEMAPHORE 0
 #define DEBUG_RW_SEMAPHORE 0
@@ -220,153 +221,6 @@
 extern inline void up(struct semaphore *sem)
 {
 	__up(sem);
-}
-#endif
-
-/* 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).
- *
- * The value 0x01000000 supports up to 128 processors and
- * lots of processes.  BIAS must be chosen such that subtracting
- * BIAS once per CPU will result in the int remaining
- * negative.
- * In terms of fairness, this should result in the lock
- * flopping back and forth between readers and writers
- * under heavy use.
- *
- *	      -ben
- *
- * Once we start supporting machines with more than 128 CPUs,
- * we should go for using a 64bit atomic type instead of 32bit
- * as counter. We shall probably go for bias 0x80000000 then,
- * so that single sethi can set it.
- *
- *	      -jj
- */
-
-#define RW_LOCK_BIAS		0x01000000
-
-struct rw_semaphore {
-	atomic_t		count;
-	/* bit 0 means read bias granted;
-	   bit 1 means write bias granted.  */
-	unsigned		granted;
-	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, __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)
-
-static inline void init_rwsem(struct rw_semaphore *sem)
-{
-	atomic_set (&sem->count, RW_LOCK_BIAS);
-	sem->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 void down_read(struct rw_semaphore *);
-extern void down_write(struct rw_semaphore *);
-extern void up_read(struct rw_semaphore *);
-extern void up_write(struct rw_semaphore *);
-extern void __down_read_failed(struct rw_semaphore *, int);
-extern void __down_write_failed(struct rw_semaphore *, int);
-extern void __rwsem_wake(struct rw_semaphore *, int);
-
-static inline void __down_read(struct rw_semaphore *sem)
-{
-	long count = atomic_dec_return(&sem->count);
-	if (__builtin_expect(count < 0, 0))
-		__down_read_failed(sem, count);
-}
-
-static inline void __down_write(struct rw_semaphore *sem)
-{
-	long count = atomic_sub_return(RW_LOCK_BIAS, &sem->count);
-	if (__builtin_expect(count != 0, 0))
-		__down_write_failed(sem, count);
-}
-
-/* When a reader does a release, the only significant case is when there
-   was a writer waiting, and we've bumped the count to 0, then we must
-   wake the writer up.  */
-
-static inline void __up_read(struct rw_semaphore *sem)
-{
-	long count;
-	mb();
-	count = atomic_inc_return(&sem->count);
-	if (__builtin_expect(count == 0, 0))
-		__rwsem_wake(sem, 0);
-}
-
-/* Releasing the writer is easy -- just release it and wake up
-   any sleepers.  */
-
-static inline void __up_write(struct rw_semaphore *sem)
-{
-	long count, wake;
-	mb();
-	count = atomic_add_return(RW_LOCK_BIAS, &sem->count);
-
-	/* Only do the wake if we were, but are no longer, negative.  */
-	wake = ((int)(count - RW_LOCK_BIAS) < 0) && count >= 0;
-	if (__builtin_expect(wake, 0))
-		__rwsem_wake(sem, count);
-}
-
-#if !WAITQUEUE_DEBUG && !DEBUG_RW_SEMAPHORE
-extern inline void down_read(struct rw_semaphore *sem)
-{
-	__down_read(sem);
-}
-extern inline void down_write(struct rw_semaphore *sem)
-{
-	__down_write(sem);
-}
-extern inline void up_read(struct rw_semaphore *sem)
-{
-	__up_read(sem);
-}
-extern inline void up_write(struct rw_semaphore *sem)
-{
-	__up_write(sem);
 }
 #endif