patch-2.4.4 linux/include/linux/rwsem-spinlock.h

• Lines: 63
• Date: Fri Apr 27 15:48:23 2001
• Orig file: v2.4.3/linux/include/linux/rwsem-spinlock.h
• Orig date: Wed Dec 31 16:00:00 1969

diff -u --recursive --new-file v2.4.3/linux/include/linux/rwsem-spinlock.h linux/include/linux/rwsem-spinlock.h
@@ -0,0 +1,62 @@
+/* rwsem-spinlock.h: fallback C implementation
+ *
+ * Copyright (c) 2001   David Howells (dhowells@redhat.com).
+ * - Derived partially from ideas by Andrea Arcangeli <andrea@suse.de>
+ * - Derived also from comments by Linus
+ */
+
+#ifndef _LINUX_RWSEM_SPINLOCK_H
+#define _LINUX_RWSEM_SPINLOCK_H
+
+#ifndef _LINUX_RWSEM_H
+#error please dont include asm/rwsem-spinlock.h directly, use linux/rwsem.h instead
+#endif
+
+#include <linux/spinlock.h>
+#include <linux/list.h>
+
+#ifdef __KERNEL__
+
+#include <linux/types.h>
+
+struct rwsem_waiter;
+
+/*
+ * the rw-semaphore definition
+ * - if activity is 0 then there are no active readers or writers
+ * - if activity is +ve then that is the number of active readers
+ * - if activity is -1 then there is one active writer
+ * - if wait_list is not empty, then there are processes waiting for the semaphore
+ */
+struct rw_semaphore {
+	__s32			activity;
+	spinlock_t		wait_lock;
+	struct list_head	wait_list;
+#if RWSEM_DEBUG
+	int			debug;
+#endif
+};
+
+/*
+ * initialisation
+ */
+#if RWSEM_DEBUG
+#define __RWSEM_DEBUG_INIT      , 0
+#else
+#define __RWSEM_DEBUG_INIT	/* */
+#endif
+
+#define __RWSEM_INITIALIZER(name) \
+{ 0, SPIN_LOCK_UNLOCKED, LIST_HEAD_INIT((name).wait_list) __RWSEM_DEBUG_INIT }
+
+#define DECLARE_RWSEM(name) \
+	struct rw_semaphore name = __RWSEM_INITIALIZER(name)
+
+extern void FASTCALL(init_rwsem(struct rw_semaphore *sem));
+extern void FASTCALL(__down_read(struct rw_semaphore *sem));
+extern void FASTCALL(__down_write(struct rw_semaphore *sem));
+extern void FASTCALL(__up_read(struct rw_semaphore *sem));
+extern void FASTCALL(__up_write(struct rw_semaphore *sem));
+
+#endif /* __KERNEL__ */
+#endif /* _LINUX_RWSEM_SPINLOCK_H */