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authorMatthew Wilcox <matthew@wil.cx>2008-03-07 21:55:58 -0500
committerMatthew Wilcox <willy@linux.intel.com>2008-04-17 10:42:34 -0400
commit64ac24e738823161693bf791f87adc802cf529ff (patch)
tree19c0b0cf314d4394ca580c05b86cdf874ce0a167 /include/asm-m68k
parente48b3deee475134585eed03e7afebe4bf9e0dba9 (diff)
downloadop-kernel-dev-64ac24e738823161693bf791f87adc802cf529ff.zip
op-kernel-dev-64ac24e738823161693bf791f87adc802cf529ff.tar.gz
Generic semaphore implementation
Semaphores are no longer performance-critical, so a generic C implementation is better for maintainability, debuggability and extensibility. Thanks to Peter Zijlstra for fixing the lockdep warning. Thanks to Harvey Harrison for pointing out that the unlikely() was unnecessary. Signed-off-by: Matthew Wilcox <willy@linux.intel.com> Acked-by: Ingo Molnar <mingo@elte.hu>
Diffstat (limited to 'include/asm-m68k')
-rw-r--r--include/asm-m68k/semaphore-helper.h142
-rw-r--r--include/asm-m68k/semaphore.h164
2 files changed, 1 insertions, 305 deletions
diff --git a/include/asm-m68k/semaphore-helper.h b/include/asm-m68k/semaphore-helper.h
deleted file mode 100644
index eef30ba..0000000
--- a/include/asm-m68k/semaphore-helper.h
+++ /dev/null
@@ -1,142 +0,0 @@
-#ifndef _M68K_SEMAPHORE_HELPER_H
-#define _M68K_SEMAPHORE_HELPER_H
-
-/*
- * SMP- and interrupt-safe semaphores helper functions.
- *
- * (C) Copyright 1996 Linus Torvalds
- *
- * m68k version by Andreas Schwab
- */
-
-#include <linux/errno.h>
-
-/*
- * These two _must_ execute atomically wrt each other.
- */
-static inline void wake_one_more(struct semaphore * sem)
-{
- atomic_inc(&sem->waking);
-}
-
-#ifndef CONFIG_RMW_INSNS
-extern spinlock_t semaphore_wake_lock;
-#endif
-
-static inline int waking_non_zero(struct semaphore *sem)
-{
- int ret;
-#ifndef CONFIG_RMW_INSNS
- unsigned long flags;
-
- spin_lock_irqsave(&semaphore_wake_lock, flags);
- ret = 0;
- if (atomic_read(&sem->waking) > 0) {
- atomic_dec(&sem->waking);
- ret = 1;
- }
- spin_unlock_irqrestore(&semaphore_wake_lock, flags);
-#else
- int tmp1, tmp2;
-
- __asm__ __volatile__
- ("1: movel %1,%2\n"
- " jle 2f\n"
- " subql #1,%2\n"
- " casl %1,%2,%3\n"
- " jne 1b\n"
- " moveq #1,%0\n"
- "2:"
- : "=d" (ret), "=d" (tmp1), "=d" (tmp2)
- : "m" (sem->waking), "0" (0), "1" (sem->waking));
-#endif
-
- return ret;
-}
-
-/*
- * waking_non_zero_interruptible:
- * 1 got the lock
- * 0 go to sleep
- * -EINTR interrupted
- */
-static inline int waking_non_zero_interruptible(struct semaphore *sem,
- struct task_struct *tsk)
-{
- int ret;
-#ifndef CONFIG_RMW_INSNS
- unsigned long flags;
-
- spin_lock_irqsave(&semaphore_wake_lock, flags);
- ret = 0;
- if (atomic_read(&sem->waking) > 0) {
- atomic_dec(&sem->waking);
- ret = 1;
- } else if (signal_pending(tsk)) {
- atomic_inc(&sem->count);
- ret = -EINTR;
- }
- spin_unlock_irqrestore(&semaphore_wake_lock, flags);
-#else
- int tmp1, tmp2;
-
- __asm__ __volatile__
- ("1: movel %1,%2\n"
- " jle 2f\n"
- " subql #1,%2\n"
- " casl %1,%2,%3\n"
- " jne 1b\n"
- " moveq #1,%0\n"
- " jra %a4\n"
- "2:"
- : "=d" (ret), "=d" (tmp1), "=d" (tmp2)
- : "m" (sem->waking), "i" (&&next), "0" (0), "1" (sem->waking));
- if (signal_pending(tsk)) {
- atomic_inc(&sem->count);
- ret = -EINTR;
- }
-next:
-#endif
-
- return ret;
-}
-
-/*
- * waking_non_zero_trylock:
- * 1 failed to lock
- * 0 got the lock
- */
-static inline int waking_non_zero_trylock(struct semaphore *sem)
-{
- int ret;
-#ifndef CONFIG_RMW_INSNS
- unsigned long flags;
-
- spin_lock_irqsave(&semaphore_wake_lock, flags);
- ret = 1;
- if (atomic_read(&sem->waking) > 0) {
- atomic_dec(&sem->waking);
- ret = 0;
- } else
- atomic_inc(&sem->count);
- spin_unlock_irqrestore(&semaphore_wake_lock, flags);
-#else
- int tmp1, tmp2;
-
- __asm__ __volatile__
- ("1: movel %1,%2\n"
- " jle 2f\n"
- " subql #1,%2\n"
- " casl %1,%2,%3\n"
- " jne 1b\n"
- " moveq #0,%0\n"
- "2:"
- : "=d" (ret), "=d" (tmp1), "=d" (tmp2)
- : "m" (sem->waking), "0" (1), "1" (sem->waking));
- if (ret)
- atomic_inc(&sem->count);
-#endif
- return ret;
-}
-
-#endif
diff --git a/include/asm-m68k/semaphore.h b/include/asm-m68k/semaphore.h
index 64d6b11..d9b2034 100644
--- a/include/asm-m68k/semaphore.h
+++ b/include/asm-m68k/semaphore.h
@@ -1,163 +1 @@
-#ifndef _M68K_SEMAPHORE_H
-#define _M68K_SEMAPHORE_H
-
-#define RW_LOCK_BIAS 0x01000000
-
-#ifndef __ASSEMBLY__
-
-#include <linux/linkage.h>
-#include <linux/wait.h>
-#include <linux/spinlock.h>
-#include <linux/rwsem.h>
-#include <linux/stringify.h>
-
-#include <asm/system.h>
-#include <asm/atomic.h>
-
-/*
- * Interrupt-safe semaphores..
- *
- * (C) Copyright 1996 Linus Torvalds
- *
- * m68k version by Andreas Schwab
- */
-
-
-struct semaphore {
- atomic_t count;
- atomic_t waking;
- wait_queue_head_t wait;
-};
-
-#define __SEMAPHORE_INITIALIZER(name, n) \
-{ \
- .count = ATOMIC_INIT(n), \
- .waking = ATOMIC_INIT(0), \
- .wait = __WAIT_QUEUE_HEAD_INITIALIZER((name).wait) \
-}
-
-#define __DECLARE_SEMAPHORE_GENERIC(name,count) \
- struct semaphore name = __SEMAPHORE_INITIALIZER(name,count)
-
-#define DECLARE_MUTEX(name) __DECLARE_SEMAPHORE_GENERIC(name,1)
-
-static inline void sema_init(struct semaphore *sem, int val)
-{
- *sem = (struct semaphore)__SEMAPHORE_INITIALIZER(*sem, val);
-}
-
-static inline void init_MUTEX (struct semaphore *sem)
-{
- sema_init(sem, 1);
-}
-
-static inline void init_MUTEX_LOCKED (struct semaphore *sem)
-{
- sema_init(sem, 0);
-}
-
-asmlinkage void __down_failed(void /* special register calling convention */);
-asmlinkage int __down_failed_interruptible(void /* params in registers */);
-asmlinkage int __down_failed_trylock(void /* params in registers */);
-asmlinkage void __up_wakeup(void /* special register calling convention */);
-
-asmlinkage void __down(struct semaphore * sem);
-asmlinkage int __down_interruptible(struct semaphore * sem);
-asmlinkage int __down_trylock(struct semaphore * sem);
-asmlinkage void __up(struct semaphore * sem);
-
-/*
- * This is ugly, but we want the default case to fall through.
- * "down_failed" is a special asm handler that calls the C
- * routine that actually waits. See arch/m68k/lib/semaphore.S
- */
-static inline void down(struct semaphore *sem)
-{
- register struct semaphore *sem1 __asm__ ("%a1") = sem;
-
- might_sleep();
- __asm__ __volatile__(
- "| atomic down operation\n\t"
- "subql #1,%0@\n\t"
- "jmi 2f\n\t"
- "1:\n"
- LOCK_SECTION_START(".even\n\t")
- "2:\tpea 1b\n\t"
- "jbra __down_failed\n"
- LOCK_SECTION_END
- : /* no outputs */
- : "a" (sem1)
- : "memory");
-}
-
-static inline int down_interruptible(struct semaphore *sem)
-{
- register struct semaphore *sem1 __asm__ ("%a1") = sem;
- register int result __asm__ ("%d0");
-
- might_sleep();
- __asm__ __volatile__(
- "| atomic interruptible down operation\n\t"
- "subql #1,%1@\n\t"
- "jmi 2f\n\t"
- "clrl %0\n"
- "1:\n"
- LOCK_SECTION_START(".even\n\t")
- "2:\tpea 1b\n\t"
- "jbra __down_failed_interruptible\n"
- LOCK_SECTION_END
- : "=d" (result)
- : "a" (sem1)
- : "memory");
- return result;
-}
-
-static inline int down_trylock(struct semaphore *sem)
-{
- register struct semaphore *sem1 __asm__ ("%a1") = sem;
- register int result __asm__ ("%d0");
-
- __asm__ __volatile__(
- "| atomic down trylock operation\n\t"
- "subql #1,%1@\n\t"
- "jmi 2f\n\t"
- "clrl %0\n"
- "1:\n"
- LOCK_SECTION_START(".even\n\t")
- "2:\tpea 1b\n\t"
- "jbra __down_failed_trylock\n"
- LOCK_SECTION_END
- : "=d" (result)
- : "a" (sem1)
- : "memory");
- return result;
-}
-
-/*
- * 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().
- */
-static inline void up(struct semaphore *sem)
-{
- register struct semaphore *sem1 __asm__ ("%a1") = sem;
-
- __asm__ __volatile__(
- "| atomic up operation\n\t"
- "addql #1,%0@\n\t"
- "jle 2f\n"
- "1:\n"
- LOCK_SECTION_START(".even\n\t")
- "2:\t"
- "pea 1b\n\t"
- "jbra __up_wakeup\n"
- LOCK_SECTION_END
- : /* no outputs */
- : "a" (sem1)
- : "memory");
-}
-
-#endif /* __ASSEMBLY__ */
-
-#endif
+#include <linux/semaphore.h>
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