patch-2.4.27 linux-2.4.27/fs/xfs/linux-2.4/mrlock.h

• Lines: 88
• Date: 2004-08-07 16:26:06.064404714 -0700
• Orig file: linux-2.4.26/fs/xfs/linux-2.4/mrlock.h
• Orig date: 1969-12-31 16:00:00.000000000 -0800

diff -urN linux-2.4.26/fs/xfs/linux-2.4/mrlock.h linux-2.4.27/fs/xfs/linux-2.4/mrlock.h
@@ -0,0 +1,87 @@
+/*
+ * Copyright (c) 2000-2003 Silicon Graphics, Inc.  All Rights Reserved.
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of version 2 of the GNU General Public License as
+ * published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it would be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
+ *
+ * Further, this software is distributed without any warranty that it is
+ * free of the rightful claim of any third person regarding infringement
+ * or the like.  Any license provided herein, whether implied or
+ * otherwise, applies only to this software file.  Patent licenses, if
+ * any, provided herein do not apply to combinations of this program with
+ * other software, or any other product whatsoever.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with this program; if not, write the Free Software Foundation, Inc., 59
+ * Temple Place - Suite 330, Boston MA 02111-1307, USA.
+ *
+ * Contact information: Silicon Graphics, Inc., 1600 Amphitheatre Pkwy,
+ * Mountain View, CA  94043, or:
+ *
+ * http://www.sgi.com
+ *
+ * For further information regarding this notice, see:
+ *
+ * http://oss.sgi.com/projects/GenInfo/SGIGPLNoticeExplan/
+ */
+#ifndef __XFS_SUPPORT_MRLOCK_H__
+#define __XFS_SUPPORT_MRLOCK_H__
+
+#include <linux/time.h>
+#include <linux/wait.h>
+#include <asm/atomic.h>
+#include <asm/semaphore.h>
+
+/*
+ * Implement mrlocks on Linux that work for XFS.
+ *
+ * These are sleep locks and not spinlocks. If one wants read/write spinlocks,
+ * use read_lock, write_lock, ... see spinlock.h.
+ */
+
+typedef struct mrlock_s {
+	int			mr_count;
+	unsigned short		mr_reads_waiting;
+	unsigned short		mr_writes_waiting;
+	wait_queue_head_t	mr_readerq;
+	wait_queue_head_t	mr_writerq;
+	spinlock_t		mr_lock;
+} mrlock_t;
+
+#define MR_ACCESS	1
+#define MR_UPDATE	2
+
+#define MRLOCK_BARRIER		0x1
+#define MRLOCK_ALLOW_EQUAL_PRI	0x8
+
+/*
+ * mraccessf/mrupdatef take flags to be passed in while sleeping;
+ * only PLTWAIT is currently supported.
+ */
+
+extern void	mraccessf(mrlock_t *, int);
+extern void	mrupdatef(mrlock_t *, int);
+extern void     mrlock(mrlock_t *, int, int);
+extern void     mrunlock(mrlock_t *);
+extern void     mraccunlock(mrlock_t *);
+extern int      mrtryupdate(mrlock_t *);
+extern int      mrtryaccess(mrlock_t *);
+extern int	mrtrypromote(mrlock_t *);
+extern void     mrdemote(mrlock_t *);
+
+extern int	ismrlocked(mrlock_t *, int);
+extern void     mrlock_init(mrlock_t *, int type, char *name, long sequence);
+extern void     mrfree(mrlock_t *);
+
+#define mrinit(mrp, name)	mrlock_init(mrp, MRLOCK_BARRIER, name, -1)
+#define mraccess(mrp)		mraccessf(mrp, 0) /* grab for READ/ACCESS */
+#define mrupdate(mrp)		mrupdatef(mrp, 0) /* grab for WRITE/UPDATE */
+#define mrislocked_access(mrp)	((mrp)->mr_count > 0)
+#define mrislocked_update(mrp)	((mrp)->mr_count < 0)
+
+#endif /* __XFS_SUPPORT_MRLOCK_H__ */