Merge with Linux 2.2.8.

1 files changed, 45 insertions, 30 deletions

diff --git a/include/asm-mips/semaphore.h b/include/asm-mips/semaphore.h
index b1ac4ecce..88c726546 100644
--- a/include/asm-mips/semaphore.h
+++ b/include/asm-mips/semaphore.h
@@ -25,42 +25,13 @@ struct semaphore {
 
 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);
 
 extern spinlock_t semaphore_wake_lock;
 
 #define sema_init(sem, val)	atomic_set(&((sem)->count), val)
 
-/*
- * These two _must_ execute atomically wrt each other.
- *
- * This is trivially done with load_locked/store_cond,
- * which we have.  Let the rest of the losers suck eggs.
- */
-
-static inline void wake_one_more(struct semaphore * sem)
-{
-	atomic_inc(&sem->waking);
-}
-
-static inline int waking_non_zero(struct semaphore *sem, struct task_struct *tsk)
-{
-	int ret, tmp;
-
-	__asm__ __volatile__(
-	"1:\tll\t%1,%2\n"
-	"blez\t%1,2f\n\t"
-	"subu\t%0,%1,1\n\t"
-	"sc\t%0,%2\n\t"
-	"beqz\t%0,1b\n\t"
-	"2:"
-	".text"
-	: "=r"(ret), "=r"(tmp), "=m"(__atomic_fool_gcc(&sem->waking))
-	: "0"(0));
-
-	return ret;
-}
-
 extern inline void down(struct semaphore * sem)
 {
 	if (atomic_dec_return(&sem->count) < 0)
@@ -76,6 +47,50 @@ extern inline int down_interruptible(struct semaphore * sem)
 }
 
 /*
+ * down_trylock returns 0 on success, 1 if we failed to get the lock.
+ *
+ * We must manipulate count and waking simultaneously and atomically.
+ * Do this by using ll/sc on the pair of 32-bit words.
+ */
+extern inline int down_trylock(struct semaphore * sem)
+{
+	long ret, tmp, tmp2, sub;
+
+#ifdef __MIPSEB__
+	__asm__ __volatile__("
+			.set	mips3
+		0:	lld	%1, %4
+			dli	%3, 0x0000000100000000
+			sltu	%0, %1, $0
+
+			bltz	%1, 1f
+			move	%3, $0
+		1:
+
+			sltu	%2, %1, $0
+			and	%0, %0, %2
+			bnez	%0, 2f
+
+			subu	%0, %3
+			scd	%1, %4
+
+			beqz	%1, 0b
+		2:
+
+			.set	mips0"
+		: "=&r"(ret), "=&r"(tmp), "=&r"(tmp2), "=&r"(sub)
+		: "m"(*sem)
+		: "memory");
+#endif
+
+#ifdef __MIPSEL__
+#error "FIXME: down_trylock doesn't support little endian machines yet."
+#endif
+
+	return ret;
+}
+
+/*
  * Note! This is subtle. We jump to wake people up only if
  * the semaphore was negative (== somebody was waiting on it).
  */