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authorpeter <peter@FreeBSD.org>1997-04-21 13:39:56 +0000
committerpeter <peter@FreeBSD.org>1997-04-21 13:39:56 +0000
commit4997aa77f1eb43ddc50a7e064389c8f6f97503b2 (patch)
treed1143e1c5073ad3ff98e5866cf22221737091e21 /sys
parent01b6917a116d10c1c4bd78295be1943a5a675b63 (diff)
downloadFreeBSD-src-4997aa77f1eb43ddc50a7e064389c8f6f97503b2.zip
FreeBSD-src-4997aa77f1eb43ddc50a7e064389c8f6f97503b2.tar.gz
Send this to the Attic so there's no mixups over which kern_lock.c is in
use in -current.
Diffstat (limited to 'sys')
-rw-r--r--sys/vm/kern_lock.c377
1 files changed, 0 insertions, 377 deletions
diff --git a/sys/vm/kern_lock.c b/sys/vm/kern_lock.c
deleted file mode 100644
index 2dce3b4..0000000
--- a/sys/vm/kern_lock.c
+++ /dev/null
@@ -1,377 +0,0 @@
-/*
- * Copyright (c) 1991, 1993
- * The Regents of the University of California. All rights reserved.
- *
- * This code is derived from software contributed to Berkeley by
- * The Mach Operating System project at Carnegie-Mellon University.
- *
- * Redistribution and use in source and binary forms, with or without
- * modification, are permitted provided that the following conditions
- * are met:
- * 1. Redistributions of source code must retain the above copyright
- * notice, this list of conditions and the following disclaimer.
- * 2. Redistributions in binary form must reproduce the above copyright
- * notice, this list of conditions and the following disclaimer in the
- * documentation and/or other materials provided with the distribution.
- * 3. All advertising materials mentioning features or use of this software
- * must display the following acknowledgement:
- * This product includes software developed by the University of
- * California, Berkeley and its contributors.
- * 4. Neither the name of the University nor the names of its contributors
- * may be used to endorse or promote products derived from this software
- * without specific prior written permission.
- *
- * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
- * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
- * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
- * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
- * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
- * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
- * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
- * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
- * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
- * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
- * SUCH DAMAGE.
- *
- * from: @(#)kern_lock.c 8.1 (Berkeley) 6/11/93
- *
- *
- * Copyright (c) 1987, 1990 Carnegie-Mellon University.
- * All rights reserved.
- *
- * Authors: Avadis Tevanian, Jr., Michael Wayne Young
- *
- * Permission to use, copy, modify and distribute this software and
- * its documentation is hereby granted, provided that both the copyright
- * notice and this permission notice appear in all copies of the
- * software, derivative works or modified versions, and any portions
- * thereof, and that both notices appear in supporting documentation.
- *
- * CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS "AS IS"
- * CONDITION. CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND
- * FOR ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE.
- *
- * Carnegie Mellon requests users of this software to return to
- *
- * Software Distribution Coordinator or Software.Distribution@CS.CMU.EDU
- * School of Computer Science
- * Carnegie Mellon University
- * Pittsburgh PA 15213-3890
- *
- * any improvements or extensions that they make and grant Carnegie the
- * rights to redistribute these changes.
- *
- * $Id$
- */
-
-/*
- * Locking primitives implementation
- */
-
-#include <sys/param.h>
-#include <sys/systm.h>
-
-/* XXX */
-#include <sys/proc.h>
-
-#include <vm/vm.h>
-#include <vm/vm_param.h>
-#include <vm/vm_prot.h>
-#include <vm/lock.h>
-
-/*
- * Routine: lock_init
- * Function:
- * Initialize a lock; required before use.
- * Note that clients declare the "struct lock"
- * variables and then initialize them, rather
- * than getting a new one from this module.
- */
-void
-lock_init(l, can_sleep)
- lock_t l;
- boolean_t can_sleep;
-{
- l->want_write = 0;
- l->want_upgrade = 0;
- l->waiting = 0;
- l->can_sleep = can_sleep;
- l->read_count = 0;
- l->proc = NULL;
- l->recursion_depth = 0;
-}
-
-void
-lock_sleepable(l, can_sleep)
- lock_t l;
- boolean_t can_sleep;
-{
- l->can_sleep = can_sleep;
-}
-
-
-/*
- * Sleep locks. These use the same data structure and algorithm
- * as the spin locks, but the process sleeps while it is waiting
- * for the lock. These work on uniprocessor systems.
- */
-
-void
-lock_write(l)
- register lock_t l;
-{
- if (l->proc == curproc) {
- /*
- * Recursive lock.
- */
- l->recursion_depth++;
- return;
- }
- /*
- * Try to acquire the want_write bit.
- */
- while (l->want_write) {
- if (l->can_sleep && l->want_write) {
- l->waiting = TRUE;
- tsleep(l, PVM, "lckwt1", 0);
- }
- }
- l->want_write = TRUE;
-
- /* Wait for readers (and upgrades) to finish */
-
- while ((l->read_count != 0) || l->want_upgrade) {
- if (l->can_sleep && (l->read_count != 0 || l->want_upgrade)) {
- l->waiting = TRUE;
- tsleep(l, PVM, "lckwt2", 0);
- }
- }
-}
-
-void
-lock_done(l)
- register lock_t l;
-{
- if (l->read_count != 0)
- l->read_count--;
- else if (l->recursion_depth != 0)
- l->recursion_depth--;
- else if (l->want_upgrade)
- l->want_upgrade = FALSE;
- else
- l->want_write = FALSE;
-
- if (l->waiting) {
- l->waiting = FALSE;
- wakeup(l);
- }
-}
-
-void
-lock_read(l)
- register lock_t l;
-{
- if (l->proc == curproc) {
- /*
- * Recursive lock.
- */
- l->read_count++;
- return;
- }
- while (l->want_write || l->want_upgrade) {
- if (l->can_sleep && (l->want_write || l->want_upgrade)) {
- l->waiting = TRUE;
- tsleep(l, PVM, "lockrd", 0);
- }
- }
-
- l->read_count++;
-}
-
-/*
- * Routine: lock_read_to_write
- * Function:
- * Improves a read-only lock to one with
- * write permission. If another reader has
- * already requested an upgrade to a write lock,
- * no lock is held upon return.
- *
- * Returns TRUE if the upgrade *failed*.
- */
-boolean_t
-lock_read_to_write(l)
- register lock_t l;
-{
- l->read_count--;
-
- if (l->proc == curproc) {
- /*
- * Recursive lock.
- */
- l->recursion_depth++;
- return (FALSE);
- }
- if (l->want_upgrade) {
- /*
- * Someone else has requested upgrade. Since we've released a
- * read lock, wake him up.
- */
- if (l->waiting) {
- l->waiting = FALSE;
- wakeup(l);
- }
- return (TRUE);
- }
- l->want_upgrade = TRUE;
-
- while (l->read_count != 0) {
- if (l->can_sleep && l->read_count != 0) {
- l->waiting = TRUE;
- tsleep(l, PVM, "lckrw", 0);
- }
- }
-
- return (FALSE);
-}
-
-void
-lock_write_to_read(l)
- register lock_t l;
-{
- l->read_count++;
- if (l->recursion_depth != 0)
- l->recursion_depth--;
- else if (l->want_upgrade)
- l->want_upgrade = FALSE;
- else
- l->want_write = FALSE;
-
- if (l->waiting) {
- l->waiting = FALSE;
- wakeup(l);
- }
-}
-
-
-/*
- * Routine: lock_try_write
- * Function:
- * Tries to get a write lock.
- *
- * Returns FALSE if the lock is not held on return.
- */
-
-boolean_t
-lock_try_write(l)
- register lock_t l;
-{
- if (l->proc == curproc) {
- /*
- * Recursive lock
- */
- l->recursion_depth++;
- return (TRUE);
- }
- if (l->want_write || l->want_upgrade || l->read_count) {
- /*
- * Can't get lock.
- */
- return (FALSE);
- }
- /*
- * Have lock.
- */
-
- l->want_write = TRUE;
- return (TRUE);
-}
-
-/*
- * Routine: lock_try_read
- * Function:
- * Tries to get a read lock.
- *
- * Returns FALSE if the lock is not held on return.
- */
-
-boolean_t
-lock_try_read(l)
- register lock_t l;
-{
- if (l->proc == curproc) {
- /*
- * Recursive lock
- */
- l->read_count++;
- return (TRUE);
- }
- if (l->want_write || l->want_upgrade) {
- return (FALSE);
- }
- l->read_count++;
- return (TRUE);
-}
-
-/*
- * Routine: lock_try_read_to_write
- * Function:
- * Improves a read-only lock to one with
- * write permission. If another reader has
- * already requested an upgrade to a write lock,
- * the read lock is still held upon return.
- *
- * Returns FALSE if the upgrade *failed*.
- */
-boolean_t
-lock_try_read_to_write(l)
- register lock_t l;
-{
- if (l->proc == curproc) {
- /*
- * Recursive lock
- */
- l->read_count--;
- l->recursion_depth++;
- return (TRUE);
- }
- if (l->want_upgrade) {
- return (FALSE);
- }
- l->want_upgrade = TRUE;
- l->read_count--;
-
- while (l->read_count != 0) {
- l->waiting = TRUE;
- tsleep(l, PVM, "lcktrw", 0);
- }
-
- return (TRUE);
-}
-
-/*
- * Allow a process that has a lock for write to acquire it
- * recursively (for read, write, or update).
- */
-void
-lock_set_recursive(l)
- lock_t l;
-{
- if (!l->want_write) {
- panic("lock_set_recursive: don't have write lock");
- }
- l->proc = curproc;
-}
-
-/*
- * Prevent a lock from being re-acquired.
- */
-void
-lock_clear_recursive(l)
- lock_t l;
-{
- if (l->proc != curproc) {
- panic("lock_clear_recursive: wrong proc");
- }
- if (l->recursion_depth == 0)
- l->proc = NULL;
-}
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