patch-2.4.6 linux/include/asm-mips/semaphore.h

• Lines: 297
• Date: Mon Jul 2 13:56:40 2001
• Orig file: v2.4.5/linux/include/asm-mips/semaphore.h
• Orig date: Tue Apr 17 17:19:31 2001

diff -u --recursive --new-file v2.4.5/linux/include/asm-mips/semaphore.h linux/include/asm-mips/semaphore.h
@@ -1,5 +1,4 @@
-/* $Id: semaphore.h,v 1.12 1999/12/08 22:05:10 harald Exp $
- *
+/*
  * SMP- and interrupt-safe semaphores..
  *
  * This file is subject to the terms and conditions of the GNU General Public
@@ -9,6 +8,7 @@
  * (C) Copyright 1996  Linus Torvalds
  * (C) Copyright 1998, 1999, 2000  Ralf Baechle
  * (C) Copyright 1999, 2000  Silicon Graphics, Inc.
+ *  Copyright (C) 2000 MIPS Technologies, Inc.  All rights reserved.
  */
 #ifndef _ASM_SEMAPHORE_H
 #define _ASM_SEMAPHORE_H
@@ -60,7 +60,7 @@
 #define DECLARE_MUTEX(name) __DECLARE_SEMAPHORE_GENERIC(name,1)
 #define DECLARE_MUTEX_LOCKED(name) __DECLARE_SEMAPHORE_GENERIC(name,0)
 
-extern inline void sema_init (struct semaphore *sem, int val)
+static inline void sema_init (struct semaphore *sem, int val)
 {
 	atomic_set(&sem->count, val);
 	atomic_set(&sem->waking, 0);
@@ -85,7 +85,7 @@
 asmlinkage int __down_trylock(struct semaphore * sem);
 asmlinkage void __up(struct semaphore * sem);
 
-extern inline void down(struct semaphore * sem)
+static inline void down(struct semaphore * sem)
 {
 #if WAITQUEUE_DEBUG
 	CHECK_MAGIC(sem->__magic);
@@ -94,7 +94,7 @@
 		__down(sem);
 }
 
-extern inline int down_interruptible(struct semaphore * sem)
+static inline int down_interruptible(struct semaphore * sem)
 {
 	int ret = 0;
 
@@ -106,9 +106,9 @@
 	return ret;
 }
 
-#if !defined(CONFIG_CPU_HAS_LLSC)
+#if !defined(CONFIG_CPU_HAS_LLSC) || defined(CONFIG_CPU_MIPS32)
 
-extern inline int down_trylock(struct semaphore * sem)
+static inline int down_trylock(struct semaphore * sem)
 {
 	int ret = 0;
 	if (atomic_dec_return(&sem->count) < 0)
@@ -140,7 +140,7 @@
  *	}
  *   }
  */
-extern inline int down_trylock(struct semaphore * sem)
+static inline int down_trylock(struct semaphore * sem)
 {
 	long ret, tmp, tmp2, sub;
 
@@ -148,29 +148,25 @@
 	CHECK_MAGIC(sem->__magic);
 #endif
 
-	__asm__ __volatile__("
-			.set	mips3
-
-		0:	lld	%1, %4
-			dli	%3, 0x0000000100000000
-			dsubu	%1, %3
-			li	%0, 0
-			bgez	%1, 2f
-			sll	%2, %1, 0
-			blez	%2, 1f
-			daddiu	%1, %1, -1
-			b	2f
-		1:
-			daddu	%1, %1, %3
-			li	%0, 1
-		2:
-			scd	%1, %4
-			beqz	%1, 0b
-
-			.set	mips0"
-		: "=&r"(ret), "=&r"(tmp), "=&r"(tmp2), "=&r"(sub)
-		: "m"(*sem)
-		: "memory");
+	__asm__ __volatile__(
+	".set\tmips3\t\t\t# down_trylock\n"
+	"0:\tlld\t%1, %4\n\t"
+	"dli\t%3, 0x0000000100000000\n\t"
+	"dsubu\t%1, %3\n\t"
+	"li\t%0, 0\n\t"
+	"bgez\t%1, 2f\n\t"
+	"sll\t%2, %1, 0\n\t"
+	"blez\t%2, 1f\n\t"
+	"daddiu\t%1, %1, -1\n\t"
+	"b\t2f\n\t"
+	"1:\tdaddu\t%1, %1, %3\n"
+	"li\t%0, 1\n"
+	"2:\tscd\t%1, %4\n\t"
+	"beqz\t%1, 0b\n\t"
+	".set	mips0"
+	: "=&r"(ret), "=&r"(tmp), "=&r"(tmp2), "=&r"(sub)
+	: "m"(*sem)
+	: "memory");
 
 	return ret;
 }
@@ -181,183 +177,13 @@
  * Note! This is subtle. We jump to wake people up only if
  * the semaphore was negative (== somebody was waiting on it).
  */
-extern inline void up(struct semaphore * sem)
+static inline void up(struct semaphore * sem)
 {
 #if WAITQUEUE_DEBUG
 	CHECK_MAGIC(sem->__magic);
 #endif
 	if (atomic_inc_return(&sem->count) <= 0)
 		__up(sem);
-}
-
-/*
- * 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.
- *
- * 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.
- * */
-
-#define RW_LOCK_BIAS		0x01000000
-
-struct rw_semaphore {
-	atomic_t		count;
-	/* bit 0 means read bias granted;
-	   bit 1 means write bias granted.  */
-	unsigned long		granted; /* pedant: long req'd for set_bit */
-	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)
-
-extern 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
-}
-
-/* The expensive part is outlined.  */
-extern void __down_read(struct rw_semaphore *sem, int count);
-extern void __down_write(struct rw_semaphore *sem, int count);
-extern void __rwsem_wake(struct rw_semaphore *sem, unsigned long readers);
-
-extern inline void down_read(struct rw_semaphore *sem)
-{
-	int count;
-
-#if WAITQUEUE_DEBUG
-	CHECK_MAGIC(sem->__magic);
-#endif
-
-	count = atomic_dec_return(&sem->count);
-	if (count < 0) {
-		__down_read(sem, count);
-	}
-	mb();
-
-#if WAITQUEUE_DEBUG
-	if (sem->granted & 2)
-		BUG();
-	if (atomic_read(&sem->writers))
-		BUG();
-	atomic_inc(&sem->readers);
-#endif
-}
-
-extern inline void down_write(struct rw_semaphore *sem)
-{
-	int count;
-
-#if WAITQUEUE_DEBUG
-	CHECK_MAGIC(sem->__magic);
-#endif
-
-	count = atomic_sub_return(RW_LOCK_BIAS, &sem->count);
-	if (count) {
-		__down_write(sem, count);
-	}
-	mb();
-
-#if WAITQUEUE_DEBUG
-	if (atomic_read(&sem->writers))
-		BUG();
-	if (atomic_read(&sem->readers))
-		BUG();
-	if (sem->granted & 3)
-		BUG();
-	atomic_inc(&sem->writers);
-#endif
-}
-
-/* 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: we must
-   wake the writer up.  */
-
-extern inline void up_read(struct rw_semaphore *sem)
-{
-#if WAITQUEUE_DEBUG
-	CHECK_MAGIC(sem->__magic);
-	if (sem->granted & 2)
-		BUG();
-	if (atomic_read(&sem->writers))
-		BUG();
-	atomic_dec(&sem->readers);
-#endif
-
-	mb();
-	if (atomic_inc_return(&sem->count) == 0)
-		__rwsem_wake(sem, 0);
-}
-
-/*
- * Releasing the writer is easy -- just release it and wake up any sleepers.
- */
-extern inline void up_write(struct rw_semaphore *sem)
-{
-	int count;
-
-#if WAITQUEUE_DEBUG
-	CHECK_MAGIC(sem->__magic);
-	if (sem->granted & 3)
-		BUG();
-	if (atomic_read(&sem->readers))
-		BUG();
-	if (atomic_read(&sem->writers) != 1)
-		BUG();
-	atomic_dec(&sem->writers);
-#endif
-
-	mb();
-	count = atomic_add_return(RW_LOCK_BIAS, &sem->count);
-	if (count - RW_LOCK_BIAS < 0 && count >= 0) {
-		/* Only do the wake if we're no longer negative.  */
-		__rwsem_wake(sem, count);
-	}
 }
 
 #endif /* _ASM_SEMAPHORE_H */