1 /* 2 * Copyright (c) 2000-2003 Silicon Graphics, Inc. All Rights Reserved. 3 * 4 * This program is free software; you can redistribute it and/or modify it 5 * under the terms of version 2 of the GNU General Public License as 6 * published by the Free Software Foundation. 7 * 8 * This program is distributed in the hope that it would be useful, but 9 * WITHOUT ANY WARRANTY; without even the implied warranty of 10 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. 11 * 12 * Further, this software is distributed without any warranty that it is 13 * free of the rightful claim of any third person regarding infringement 14 * or the like. Any license provided herein, whether implied or 15 * otherwise, applies only to this software file. Patent licenses, if 16 * any, provided herein do not apply to combinations of this program with 17 * other software, or any other product whatsoever. 18 * 19 * You should have received a copy of the GNU General Public License along 20 * with this program; if not, write the Free Software Foundation, Inc., 59 21 * Temple Place - Suite 330, Boston MA 02111-1307, USA. 22 * 23 * Contact information: Silicon Graphics, Inc., 1600 Amphitheatre Pkwy, 24 * Mountain View, CA 94043, or: 25 * 26 * http://www.sgi.com 27 * 28 * For further information regarding this notice, see: 29 * 30 * http://oss.sgi.com/projects/GenInfo/SGIGPLNoticeExplan/ 31 */ 32 #ifndef __XFS_SUPPORT_MRLOCK_H__ 33 #define __XFS_SUPPORT_MRLOCK_H__ 34 35 #include <linux/time.h> 36 #include <linux/wait.h> 37 #include <asm/atomic.h> 38 #include <asm/semaphore.h> 39 40 /* 41 * Implement mrlocks on Linux that work for XFS. 42 * 43 * These are sleep locks and not spinlocks. If one wants read/write spinlocks, 44 * use read_lock, write_lock, ... see spinlock.h. 45 */ 46 47 typedef struct mrlock_s { 48 int mr_count; 49 unsigned short mr_reads_waiting; 50 unsigned short mr_writes_waiting; 51 wait_queue_head_t mr_readerq; 52 wait_queue_head_t mr_writerq; 53 spinlock_t mr_lock; 54 } mrlock_t; 55 56 #define MR_ACCESS 1 57 #define MR_UPDATE 2 58 59 #define MRLOCK_BARRIER 0x1 60 #define MRLOCK_ALLOW_EQUAL_PRI 0x8 61 62 /* 63 * mraccessf/mrupdatef take flags to be passed in while sleeping; 64 * only PLTWAIT is currently supported. 65 */ 66 67 extern void mraccessf(mrlock_t *, int); 68 extern void mrupdatef(mrlock_t *, int); 69 extern void mrlock(mrlock_t *, int, int); 70 extern void mrunlock(mrlock_t *); 71 extern void mraccunlock(mrlock_t *); 72 extern int mrtryupdate(mrlock_t *); 73 extern int mrtryaccess(mrlock_t *); 74 extern int mrtrypromote(mrlock_t *); 75 extern void mrdemote(mrlock_t *); 76 77 extern int ismrlocked(mrlock_t *, int); 78 extern void mrlock_init(mrlock_t *, int type, char *name, long sequence); 79 extern void mrfree(mrlock_t *); 80 81 #define mrinit(mrp, name) mrlock_init(mrp, MRLOCK_BARRIER, name, -1) 82 #define mraccess(mrp) mraccessf(mrp, 0) /* grab for READ/ACCESS */ 83 #define mrupdate(mrp) mrupdatef(mrp, 0) /* grab for WRITE/UPDATE */ 84 #define mrislocked_access(mrp) ((mrp)->mr_count > 0) 85 #define mrislocked_update(mrp) ((mrp)->mr_count < 0) 86 87 #endif /* __XFS_SUPPORT_MRLOCK_H__ */ 88