patch-2.4.27 linux-2.4.27/fs/xfs/linux/mrlock.c

• Lines: 275
• Date: 1969-12-31 16:00:00.000000000 -0800
• Orig file: linux-2.4.26/fs/xfs/linux/mrlock.c
• Orig date: 2004-02-18 05:36:31.000000000 -0800

diff -urN linux-2.4.26/fs/xfs/linux/mrlock.c linux-2.4.27/fs/xfs/linux/mrlock.c
@@ -1,274 +0,0 @@
-/*
- * 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/
- */
-
-#include <linux/time.h>
-#include <linux/sched.h>
-#include <asm/system.h>
-#include <linux/interrupt.h>
-#include <asm/current.h>
-
-#include "mrlock.h"
-
-
-#if USE_RW_WAIT_QUEUE_SPINLOCK
-# define wq_write_lock	write_lock
-#else
-# define wq_write_lock	spin_lock
-#endif
-
-/*
- * We don't seem to need lock_type (only one supported), name, or
- * sequence. But, XFS will pass it so let's leave them here for now.
- */
-/* ARGSUSED */
-void
-mrlock_init(mrlock_t *mrp, int lock_type, char *name, long sequence)
-{
-	mrp->mr_count = 0;
-	mrp->mr_reads_waiting = 0;
-	mrp->mr_writes_waiting = 0;
-	init_waitqueue_head(&mrp->mr_readerq);
-	init_waitqueue_head(&mrp->mr_writerq);
-	mrp->mr_lock = SPIN_LOCK_UNLOCKED;
-}
-
-/*
- * Macros to lock/unlock the mrlock_t.
- */
-
-#define MRLOCK(m)		spin_lock(&(m)->mr_lock);
-#define MRUNLOCK(m)		spin_unlock(&(m)->mr_lock);
-
-
-/*
- * lock_wait should never be called in an interrupt thread.
- *
- * mrlocks can sleep (i.e. call schedule) and so they can't ever
- * be called from an interrupt thread.
- *
- * threads that wake-up should also never be invoked from interrupt threads.
- *
- * But, waitqueue_lock is locked from interrupt threads - and we are
- * called with interrupts disabled, so it is all OK.
- */
-
-/* ARGSUSED */
-void
-lock_wait(wait_queue_head_t *q, spinlock_t *lock, int rw)
-{
-	DECLARE_WAITQUEUE( wait, current );
-
-	__set_current_state(TASK_UNINTERRUPTIBLE);
-
-	wq_write_lock(&q->lock);
-	if (rw) {
-		__add_wait_queue_tail(q, &wait);
-	} else {
-		__add_wait_queue(q, &wait);
-	}
-
-	wq_write_unlock(&q->lock);
-	spin_unlock(lock);
-
-	schedule();
-
-	wq_write_lock(&q->lock);
-	__remove_wait_queue(q, &wait);
-	wq_write_unlock(&q->lock);
-
-	spin_lock(lock);
-
-	/* return with lock held */
-}
-
-/* ARGSUSED */
-void
-mrfree(mrlock_t *mrp)
-{
-}
-
-/* ARGSUSED */
-void
-mrlock(mrlock_t *mrp, int type, int flags)
-{
-	if (type == MR_ACCESS)
-		mraccess(mrp);
-	else
-		mrupdate(mrp);
-}
-
-/* ARGSUSED */
-void
-mraccessf(mrlock_t *mrp, int flags)
-{
-	MRLOCK(mrp);
-	if(mrp->mr_writes_waiting > 0) {
-		mrp->mr_reads_waiting++;
-		lock_wait(&mrp->mr_readerq, &mrp->mr_lock, 0);
-		mrp->mr_reads_waiting--;
-	}
-	while (mrp->mr_count < 0) {
-		mrp->mr_reads_waiting++;
-		lock_wait(&mrp->mr_readerq, &mrp->mr_lock, 0);
-		mrp->mr_reads_waiting--;
-	}
-	mrp->mr_count++;
-	MRUNLOCK(mrp);
-}
-
-/* ARGSUSED */
-void
-mrupdatef(mrlock_t *mrp, int flags)
-{
-	MRLOCK(mrp);
-	while(mrp->mr_count) {
-		mrp->mr_writes_waiting++;
-		lock_wait(&mrp->mr_writerq, &mrp->mr_lock, 1);
-		mrp->mr_writes_waiting--;
-	}
-
-	mrp->mr_count = -1; /* writer on it */
-	MRUNLOCK(mrp);
-}
-
-int
-mrtryaccess(mrlock_t *mrp)
-{
-	MRLOCK(mrp);
-	/*
-	 * If anyone is waiting for update access or the lock is held for update
-	 * fail the request.
-	 */
-	if(mrp->mr_writes_waiting > 0 || mrp->mr_count < 0) {
-		MRUNLOCK(mrp);
-		return 0;
-	}
-	mrp->mr_count++;
-	MRUNLOCK(mrp);
-	return 1;
-}
-
-int
-mrtrypromote(mrlock_t *mrp)
-{
-	MRLOCK(mrp);
-
-	if(mrp->mr_count == 1) { /* We are the only thread with the lock */
-		mrp->mr_count = -1; /* writer on it */
-		MRUNLOCK(mrp);
-		return 1;
-	}
-
-	MRUNLOCK(mrp);
-	return 0;
-}
-
-int
-mrtryupdate(mrlock_t *mrp)
-{
-	MRLOCK(mrp);
-
-	if(mrp->mr_count) {
-		MRUNLOCK(mrp);
-		return 0;
-	}
-
-	mrp->mr_count = -1; /* writer on it */
-	MRUNLOCK(mrp);
-	return 1;
-}
-
-static __inline__ void mrwake(mrlock_t *mrp)
-{
-	/*
-	 * First, if the count is now 0, we need to wake-up anyone waiting.
-	 */
-	if (!mrp->mr_count) {
-		if (mrp->mr_writes_waiting) {	/* Wake-up first writer waiting */
-			wake_up(&mrp->mr_writerq);
-		} else if (mrp->mr_reads_waiting) {	/* Wakeup any readers waiting */
-			wake_up(&mrp->mr_readerq);
-		}
-	}
-}
-
-void
-mraccunlock(mrlock_t *mrp)
-{
-	MRLOCK(mrp);
-	mrp->mr_count--;
-	mrwake(mrp);
-	MRUNLOCK(mrp);
-}
-
-void
-mrunlock(mrlock_t *mrp)
-{
-	MRLOCK(mrp);
-	if (mrp->mr_count < 0) {
-		mrp->mr_count = 0;
-	} else {
-		mrp->mr_count--;
-	}
-	mrwake(mrp);
-	MRUNLOCK(mrp);
-}
-
-int
-ismrlocked(mrlock_t *mrp, int type)	/* No need to lock since info can change */
-{
-	if (type == MR_ACCESS)
-		return (mrp->mr_count > 0); /* Read lock */
-	else if (type == MR_UPDATE)
-		return (mrp->mr_count < 0); /* Write lock */
-	else if (type == (MR_UPDATE | MR_ACCESS))
-		return (mrp->mr_count);	/* Any type of lock held */
-	else /* Any waiters */
-		return (mrp->mr_reads_waiting | mrp->mr_writes_waiting);
-}
-
-/*
- * Demote from update to access. We better be the only thread with the
- * lock in update mode so it should be easy to set to 1.
- * Wake-up any readers waiting.
- */
-
-void
-mrdemote(mrlock_t *mrp)
-{
-	MRLOCK(mrp);
-	mrp->mr_count = 1;
-	if (mrp->mr_reads_waiting) {	/* Wakeup all readers waiting */
-		wake_up(&mrp->mr_readerq);
-	}
-	MRUNLOCK(mrp);
-}