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>

1 files changed, 1 insertions, 192 deletions

diff --git a/include/asm-sparc/semaphore.h b/include/asm-sparc/semaphore.h
index 8018f9f..d9b2034 100644
--- a/include/asm-sparc/semaphore.h
+++ b/include/asm-sparc/semaphore.h
@@ -1,192 +1 @@
-#ifndef _SPARC_SEMAPHORE_H
-#define _SPARC_SEMAPHORE_H
-
-/* Dinky, good for nothing, just barely irq safe, Sparc semaphores. */
-
-#ifdef __KERNEL__
-
-#include <asm/atomic.h>
-#include <linux/wait.h>
-#include <linux/rwsem.h>
-
-struct semaphore {
-	atomic24_t count;
-	int sleepers;
-	wait_queue_head_t wait;
-};
-
-#define __SEMAPHORE_INITIALIZER(name, n)				\
-{									\
-	.count		= ATOMIC24_INIT(n),				\
-	.sleepers	= 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)
-{
-	atomic24_set(&sem->count, val);
-	sem->sleepers = 0;
-	init_waitqueue_head(&sem->wait);
-}
-
-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);
-}
-
-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);
-
-static inline void down(struct semaphore * sem)
-{
-	register volatile int *ptr asm("g1");
-	register int increment asm("g2");
-
-	might_sleep();
-
-	ptr = &(sem->count.counter);
-	increment = 1;
-
-	__asm__ __volatile__(
-	"mov	%%o7, %%g4\n\t"
-	"call	___atomic24_sub\n\t"
-	" add	%%o7, 8, %%o7\n\t"
-	"tst	%%g2\n\t"
-	"bl	2f\n\t"
-	" nop\n"
-	"1:\n\t"
-	".subsection 2\n"
-	"2:\n\t"
-	"save	%%sp, -64, %%sp\n\t"
-	"mov	%%g1, %%l1\n\t"
-	"mov	%%g5, %%l5\n\t"
-	"call	%3\n\t"
-	" mov	%%g1, %%o0\n\t"
-	"mov	%%l1, %%g1\n\t"
-	"ba	1b\n\t"
-	" restore %%l5, %%g0, %%g5\n\t"
-	".previous\n"
-	: "=&r" (increment)
-	: "0" (increment), "r" (ptr), "i" (__down)
-	: "g3", "g4", "g7", "memory", "cc");
-}
-
-static inline int down_interruptible(struct semaphore * sem)
-{
-	register volatile int *ptr asm("g1");
-	register int increment asm("g2");
-
-	might_sleep();
-
-	ptr = &(sem->count.counter);
-	increment = 1;
-
-	__asm__ __volatile__(
-	"mov	%%o7, %%g4\n\t"
-	"call	___atomic24_sub\n\t"
-	" add	%%o7, 8, %%o7\n\t"
-	"tst	%%g2\n\t"
-	"bl	2f\n\t"
-	" clr	%%g2\n"
-	"1:\n\t"
-	".subsection 2\n"
-	"2:\n\t"
-	"save	%%sp, -64, %%sp\n\t"
-	"mov	%%g1, %%l1\n\t"
-	"mov	%%g5, %%l5\n\t"
-	"call	%3\n\t"
-	" mov	%%g1, %%o0\n\t"
-	"mov	%%l1, %%g1\n\t"
-	"mov	%%l5, %%g5\n\t"
-	"ba	1b\n\t"
-	" restore %%o0, %%g0, %%g2\n\t"
-	".previous\n"
-	: "=&r" (increment)
-	: "0" (increment), "r" (ptr), "i" (__down_interruptible)
-	: "g3", "g4", "g7", "memory", "cc");
-
-	return increment;
-}
-
-static inline int down_trylock(struct semaphore * sem)
-{
-	register volatile int *ptr asm("g1");
-	register int increment asm("g2");
-
-	ptr = &(sem->count.counter);
-	increment = 1;
-
-	__asm__ __volatile__(
-	"mov	%%o7, %%g4\n\t"
-	"call	___atomic24_sub\n\t"
-	" add	%%o7, 8, %%o7\n\t"
-	"tst	%%g2\n\t"
-	"bl	2f\n\t"
-	" clr	%%g2\n"
-	"1:\n\t"
-	".subsection 2\n"
-	"2:\n\t"
-	"save	%%sp, -64, %%sp\n\t"
-	"mov	%%g1, %%l1\n\t"
-	"mov	%%g5, %%l5\n\t"
-	"call	%3\n\t"
-	" mov	%%g1, %%o0\n\t"
-	"mov	%%l1, %%g1\n\t"
-	"mov	%%l5, %%g5\n\t"
-	"ba	1b\n\t"
-	" restore %%o0, %%g0, %%g2\n\t"
-	".previous\n"
-	: "=&r" (increment)
-	: "0" (increment), "r" (ptr), "i" (__down_trylock)
-	: "g3", "g4", "g7", "memory", "cc");
-
-	return increment;
-}
-
-static inline void up(struct semaphore * sem)
-{
-	register volatile int *ptr asm("g1");
-	register int increment asm("g2");
-
-	ptr = &(sem->count.counter);
-	increment = 1;
-
-	__asm__ __volatile__(
-	"mov	%%o7, %%g4\n\t"
-	"call	___atomic24_add\n\t"
-	" add	%%o7, 8, %%o7\n\t"
-	"tst	%%g2\n\t"
-	"ble	2f\n\t"
-	" nop\n"
-	"1:\n\t"
-	".subsection 2\n"
-	"2:\n\t"
-	"save	%%sp, -64, %%sp\n\t"
-	"mov	%%g1, %%l1\n\t"
-	"mov	%%g5, %%l5\n\t"
-	"call	%3\n\t"
-	" mov	%%g1, %%o0\n\t"
-	"mov	%%l1, %%g1\n\t"
-	"ba	1b\n\t"
-	" restore %%l5, %%g0, %%g5\n\t"
-	".previous\n"
-	: "=&r" (increment)
-	: "0" (increment), "r" (ptr), "i" (__up)
-	: "g3", "g4", "g7", "memory", "cc");
-}	
-
-#endif /* __KERNEL__ */
-
-#endif /* !(_SPARC_SEMAPHORE_H) */
+#include <linux/semaphore.h>