patch-2.0.19 linux/include/asm-alpha/semaphore.h

• Lines: 44
• Date: Wed Sep 11 14:18:02 1996
• Orig file: v2.0.18/linux/include/asm-alpha/semaphore.h
• Orig date: Thu Jan 1 02:00:00 1970

diff -u --recursive --new-file v2.0.18/linux/include/asm-alpha/semaphore.h linux/include/asm-alpha/semaphore.h
@@ -0,0 +1,43 @@
+#ifndef _ALPHA_SEMAPHORE_H
+#define _ALPHA_SEMAPHORE_H
+
+/*
+ * SMP- and interrupt-safe semaphores..
+ *
+ * (C) Copyright 1996 Linus Torvalds
+ */
+
+struct semaphore {
+	int count;
+	int waiting;
+	struct wait_queue * wait;
+};
+
+#define MUTEX ((struct semaphore) { 1, 0, NULL })
+#define MUTEX_LOCKED ((struct semaphore) { 0, 0, NULL })
+
+extern void __down(struct semaphore * sem);
+extern void wake_up(struct wait_queue ** p);
+
+/*
+ * These are not yet interrupt-safe: should use ldl_l/stl_c here..
+ *
+ * See include/asm-i386/semaphore.h on how to do this correctly
+ * without any jumps or wakeups taken for the no-contention cases.
+ */
+extern inline void down(struct semaphore * sem)
+{
+	sem->count--;
+	/* "down_failed" */
+	if (sem->count < 0)
+		__down(sem);
+}
+
+extern inline void up(struct semaphore * sem)
+{
+	sem->count++;
+	/* "up_wakeup" */
+	__up(sem);
+}	
+
+#endif