588 lines
16 KiB
C
588 lines
16 KiB
C
/*-
|
|
* Copyright (c) 1995
|
|
* The Regents of the University of California. All rights reserved.
|
|
*
|
|
* Copyright (C) 1997
|
|
* John S. Dyson. All rights reserved.
|
|
*
|
|
* This code contains ideas from software contributed to Berkeley by
|
|
* Avadis Tevanian, Jr., Michael Wayne Young, and 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.
|
|
*
|
|
* @(#)kern_lock.c 8.18 (Berkeley) 5/21/95
|
|
*/
|
|
|
|
#include <sys/cdefs.h>
|
|
__FBSDID("$FreeBSD$");
|
|
|
|
#include <sys/param.h>
|
|
#include <sys/kernel.h>
|
|
#include <sys/ktr.h>
|
|
#include <sys/lock.h>
|
|
#include <sys/lockmgr.h>
|
|
#include <sys/mutex.h>
|
|
#include <sys/proc.h>
|
|
#include <sys/systm.h>
|
|
|
|
/*
|
|
* Locking primitives implementation.
|
|
* Locks provide shared/exclusive sychronization.
|
|
*/
|
|
|
|
#define COUNT(td, x) if ((td)) (td)->td_locks += (x)
|
|
#define LK_ALL (LK_HAVE_EXCL | LK_WANT_EXCL | LK_WANT_UPGRADE | \
|
|
LK_SHARE_NONZERO | LK_WAIT_NONZERO)
|
|
|
|
static int acquire(struct lock **lkpp, int extflags, int wanted);
|
|
static int acquiredrain(struct lock *lkp, int extflags) ;
|
|
|
|
static __inline void
|
|
sharelock(struct thread *td, struct lock *lkp, int incr) {
|
|
lkp->lk_flags |= LK_SHARE_NONZERO;
|
|
lkp->lk_sharecount += incr;
|
|
COUNT(td, incr);
|
|
}
|
|
|
|
static __inline void
|
|
shareunlock(struct thread *td, struct lock *lkp, int decr) {
|
|
|
|
KASSERT(lkp->lk_sharecount >= decr, ("shareunlock: count < decr"));
|
|
|
|
COUNT(td, -decr);
|
|
if (lkp->lk_sharecount == decr) {
|
|
lkp->lk_flags &= ~LK_SHARE_NONZERO;
|
|
if (lkp->lk_flags & (LK_WANT_UPGRADE | LK_WANT_EXCL)) {
|
|
wakeup(lkp);
|
|
}
|
|
lkp->lk_sharecount = 0;
|
|
} else {
|
|
lkp->lk_sharecount -= decr;
|
|
}
|
|
}
|
|
|
|
static int
|
|
acquire(struct lock **lkpp, int extflags, int wanted)
|
|
{
|
|
struct lock *lkp = *lkpp;
|
|
int error;
|
|
CTR3(KTR_LOCK,
|
|
"acquire(): lkp == %p, extflags == 0x%x, wanted == 0x%x",
|
|
lkp, extflags, wanted);
|
|
|
|
if ((extflags & LK_NOWAIT) && (lkp->lk_flags & wanted))
|
|
return EBUSY;
|
|
error = 0;
|
|
while ((lkp->lk_flags & wanted) != 0) {
|
|
CTR2(KTR_LOCK,
|
|
"acquire(): lkp == %p, lk_flags == 0x%x sleeping",
|
|
lkp, lkp->lk_flags);
|
|
lkp->lk_flags |= LK_WAIT_NONZERO;
|
|
lkp->lk_waitcount++;
|
|
error = msleep(lkp, lkp->lk_interlock, lkp->lk_prio,
|
|
lkp->lk_wmesg,
|
|
((extflags & LK_TIMELOCK) ? lkp->lk_timo : 0));
|
|
lkp->lk_waitcount--;
|
|
if (lkp->lk_waitcount == 0)
|
|
lkp->lk_flags &= ~LK_WAIT_NONZERO;
|
|
if (error)
|
|
break;
|
|
if (extflags & LK_SLEEPFAIL) {
|
|
error = ENOLCK;
|
|
break;
|
|
}
|
|
if (lkp->lk_newlock != NULL) {
|
|
mtx_lock(lkp->lk_newlock->lk_interlock);
|
|
mtx_unlock(lkp->lk_interlock);
|
|
if (lkp->lk_waitcount == 0)
|
|
wakeup((void *)(&lkp->lk_newlock));
|
|
*lkpp = lkp = lkp->lk_newlock;
|
|
}
|
|
}
|
|
mtx_assert(lkp->lk_interlock, MA_OWNED);
|
|
return (error);
|
|
}
|
|
|
|
/*
|
|
* Set, change, or release a lock.
|
|
*
|
|
* Shared requests increment the shared count. Exclusive requests set the
|
|
* LK_WANT_EXCL flag (preventing further shared locks), and wait for already
|
|
* accepted shared locks and shared-to-exclusive upgrades to go away.
|
|
*/
|
|
int
|
|
#ifndef DEBUG_LOCKS
|
|
lockmgr(lkp, flags, interlkp, td)
|
|
#else
|
|
debuglockmgr(lkp, flags, interlkp, td, name, file, line)
|
|
#endif
|
|
struct lock *lkp;
|
|
u_int flags;
|
|
struct mtx *interlkp;
|
|
struct thread *td;
|
|
#ifdef DEBUG_LOCKS
|
|
const char *name; /* Name of lock function */
|
|
const char *file; /* Name of file call is from */
|
|
int line; /* Line number in file */
|
|
#endif
|
|
{
|
|
int error;
|
|
struct thread *thr;
|
|
int extflags, lockflags;
|
|
|
|
error = 0;
|
|
if (td == NULL)
|
|
thr = LK_KERNPROC;
|
|
else
|
|
thr = td;
|
|
|
|
if ((flags & LK_INTERNAL) == 0)
|
|
mtx_lock(lkp->lk_interlock);
|
|
#ifdef DEBUG_LOCKS
|
|
CTR6(KTR_LOCK,
|
|
"lockmgr(): lkp == %p (lk_wmesg == \"%s\"), flags == 0x%x, "
|
|
"td == %p %s:%d", lkp, lkp->lk_wmesg, flags, td, file, line);
|
|
#else
|
|
CTR6(KTR_LOCK,
|
|
"lockmgr(): lkp == %p (lk_wmesg == \"%s\"), owner == %p, exclusivecount == %d, flags == 0x%x, "
|
|
"td == %p", lkp, lkp->lk_wmesg, lkp->lk_lockholder,
|
|
lkp->lk_exclusivecount, flags, td);
|
|
#endif
|
|
|
|
if (flags & LK_INTERLOCK) {
|
|
mtx_assert(interlkp, MA_OWNED | MA_NOTRECURSED);
|
|
mtx_unlock(interlkp);
|
|
}
|
|
|
|
if ((flags & (LK_NOWAIT|LK_RELEASE)) == 0)
|
|
WITNESS_WARN(WARN_GIANTOK | WARN_SLEEPOK,
|
|
&lkp->lk_interlock->mtx_object,
|
|
"Acquiring lockmgr lock \"%s\"", lkp->lk_wmesg);
|
|
|
|
if (panicstr != NULL) {
|
|
mtx_unlock(lkp->lk_interlock);
|
|
return (0);
|
|
}
|
|
if ((lkp->lk_flags & LK_NOSHARE) &&
|
|
(flags & LK_TYPE_MASK) == LK_SHARED) {
|
|
flags &= ~LK_TYPE_MASK;
|
|
flags |= LK_EXCLUSIVE;
|
|
}
|
|
extflags = (flags | lkp->lk_flags) & LK_EXTFLG_MASK;
|
|
|
|
switch (flags & LK_TYPE_MASK) {
|
|
|
|
case LK_SHARED:
|
|
/*
|
|
* If we are not the exclusive lock holder, we have to block
|
|
* while there is an exclusive lock holder or while an
|
|
* exclusive lock request or upgrade request is in progress.
|
|
*
|
|
* However, if TDP_DEADLKTREAT is set, we override exclusive
|
|
* lock requests or upgrade requests ( but not the exclusive
|
|
* lock itself ).
|
|
*/
|
|
if (lkp->lk_lockholder != thr) {
|
|
lockflags = LK_HAVE_EXCL;
|
|
if (td != NULL && !(td->td_pflags & TDP_DEADLKTREAT))
|
|
lockflags |= LK_WANT_EXCL | LK_WANT_UPGRADE;
|
|
error = acquire(&lkp, extflags, lockflags);
|
|
if (error)
|
|
break;
|
|
sharelock(td, lkp, 1);
|
|
#if defined(DEBUG_LOCKS)
|
|
lkp->lk_slockholder = thr;
|
|
lkp->lk_sfilename = file;
|
|
lkp->lk_slineno = line;
|
|
lkp->lk_slockername = name;
|
|
#endif
|
|
break;
|
|
}
|
|
/*
|
|
* We hold an exclusive lock, so downgrade it to shared.
|
|
* An alternative would be to fail with EDEADLK.
|
|
*/
|
|
sharelock(td, lkp, 1);
|
|
/* FALLTHROUGH downgrade */
|
|
|
|
case LK_DOWNGRADE:
|
|
KASSERT(lkp->lk_lockholder == thr && lkp->lk_exclusivecount != 0,
|
|
("lockmgr: not holding exclusive lock "
|
|
"(owner thread (%p) != thread (%p), exlcnt (%d) != 0",
|
|
lkp->lk_lockholder, thr, lkp->lk_exclusivecount));
|
|
sharelock(td, lkp, lkp->lk_exclusivecount);
|
|
COUNT(td, -lkp->lk_exclusivecount);
|
|
lkp->lk_exclusivecount = 0;
|
|
lkp->lk_flags &= ~LK_HAVE_EXCL;
|
|
lkp->lk_lockholder = LK_NOPROC;
|
|
if (lkp->lk_waitcount)
|
|
wakeup((void *)lkp);
|
|
break;
|
|
|
|
case LK_EXCLUPGRADE:
|
|
/*
|
|
* If another process is ahead of us to get an upgrade,
|
|
* then we want to fail rather than have an intervening
|
|
* exclusive access.
|
|
*/
|
|
if (lkp->lk_flags & LK_WANT_UPGRADE) {
|
|
shareunlock(td, lkp, 1);
|
|
error = EBUSY;
|
|
break;
|
|
}
|
|
/* FALLTHROUGH normal upgrade */
|
|
|
|
case LK_UPGRADE:
|
|
/*
|
|
* Upgrade a shared lock to an exclusive one. If another
|
|
* shared lock has already requested an upgrade to an
|
|
* exclusive lock, our shared lock is released and an
|
|
* exclusive lock is requested (which will be granted
|
|
* after the upgrade). If we return an error, the file
|
|
* will always be unlocked.
|
|
*/
|
|
if (lkp->lk_lockholder == thr)
|
|
panic("lockmgr: upgrade exclusive lock");
|
|
if (lkp->lk_sharecount <= 0)
|
|
panic("lockmgr: upgrade without shared");
|
|
shareunlock(td, lkp, 1);
|
|
/*
|
|
* If we are just polling, check to see if we will block.
|
|
*/
|
|
if ((extflags & LK_NOWAIT) &&
|
|
((lkp->lk_flags & LK_WANT_UPGRADE) ||
|
|
lkp->lk_sharecount > 1)) {
|
|
error = EBUSY;
|
|
break;
|
|
}
|
|
if ((lkp->lk_flags & LK_WANT_UPGRADE) == 0) {
|
|
/*
|
|
* We are first shared lock to request an upgrade, so
|
|
* request upgrade and wait for the shared count to
|
|
* drop to zero, then take exclusive lock.
|
|
*/
|
|
lkp->lk_flags |= LK_WANT_UPGRADE;
|
|
error = acquire(&lkp, extflags, LK_SHARE_NONZERO);
|
|
lkp->lk_flags &= ~LK_WANT_UPGRADE;
|
|
|
|
if (error) {
|
|
if ((lkp->lk_flags & ( LK_WANT_EXCL | LK_WAIT_NONZERO)) == (LK_WANT_EXCL | LK_WAIT_NONZERO))
|
|
wakeup((void *)lkp);
|
|
break;
|
|
}
|
|
if (lkp->lk_exclusivecount != 0)
|
|
panic("lockmgr: non-zero exclusive count");
|
|
lkp->lk_flags |= LK_HAVE_EXCL;
|
|
lkp->lk_lockholder = thr;
|
|
lkp->lk_exclusivecount = 1;
|
|
COUNT(td, 1);
|
|
#if defined(DEBUG_LOCKS)
|
|
lkp->lk_filename = file;
|
|
lkp->lk_lineno = line;
|
|
lkp->lk_lockername = name;
|
|
#endif
|
|
break;
|
|
}
|
|
/*
|
|
* Someone else has requested upgrade. Release our shared
|
|
* lock, awaken upgrade requestor if we are the last shared
|
|
* lock, then request an exclusive lock.
|
|
*/
|
|
if ( (lkp->lk_flags & (LK_SHARE_NONZERO|LK_WAIT_NONZERO)) ==
|
|
LK_WAIT_NONZERO)
|
|
wakeup((void *)lkp);
|
|
/* FALLTHROUGH exclusive request */
|
|
|
|
case LK_EXCLUSIVE:
|
|
if (lkp->lk_lockholder == thr && thr != LK_KERNPROC) {
|
|
/*
|
|
* Recursive lock.
|
|
*/
|
|
if ((extflags & (LK_NOWAIT | LK_CANRECURSE)) == 0)
|
|
panic("lockmgr: locking against myself");
|
|
if ((extflags & LK_CANRECURSE) != 0) {
|
|
lkp->lk_exclusivecount++;
|
|
COUNT(td, 1);
|
|
break;
|
|
}
|
|
}
|
|
/*
|
|
* If we are just polling, check to see if we will sleep.
|
|
*/
|
|
if ((extflags & LK_NOWAIT) &&
|
|
(lkp->lk_flags & (LK_HAVE_EXCL | LK_WANT_EXCL | LK_WANT_UPGRADE | LK_SHARE_NONZERO))) {
|
|
error = EBUSY;
|
|
break;
|
|
}
|
|
/*
|
|
* Try to acquire the want_exclusive flag.
|
|
*/
|
|
error = acquire(&lkp, extflags, (LK_HAVE_EXCL | LK_WANT_EXCL));
|
|
if (error)
|
|
break;
|
|
lkp->lk_flags |= LK_WANT_EXCL;
|
|
/*
|
|
* Wait for shared locks and upgrades to finish.
|
|
*/
|
|
error = acquire(&lkp, extflags, LK_HAVE_EXCL | LK_WANT_UPGRADE | LK_SHARE_NONZERO);
|
|
lkp->lk_flags &= ~LK_WANT_EXCL;
|
|
if (error) {
|
|
if (lkp->lk_flags & LK_WAIT_NONZERO)
|
|
wakeup((void *)lkp);
|
|
break;
|
|
}
|
|
lkp->lk_flags |= LK_HAVE_EXCL;
|
|
lkp->lk_lockholder = thr;
|
|
if (lkp->lk_exclusivecount != 0)
|
|
panic("lockmgr: non-zero exclusive count");
|
|
lkp->lk_exclusivecount = 1;
|
|
COUNT(td, 1);
|
|
#if defined(DEBUG_LOCKS)
|
|
lkp->lk_filename = file;
|
|
lkp->lk_lineno = line;
|
|
lkp->lk_lockername = name;
|
|
#endif
|
|
break;
|
|
|
|
case LK_RELEASE:
|
|
if (lkp->lk_exclusivecount != 0) {
|
|
if (lkp->lk_lockholder != thr &&
|
|
lkp->lk_lockholder != LK_KERNPROC) {
|
|
panic("lockmgr: thread %p, not %s %p unlocking",
|
|
thr, "exclusive lock holder",
|
|
lkp->lk_lockholder);
|
|
}
|
|
if (lkp->lk_lockholder != LK_KERNPROC)
|
|
COUNT(td, -1);
|
|
if (lkp->lk_exclusivecount == 1) {
|
|
lkp->lk_flags &= ~LK_HAVE_EXCL;
|
|
lkp->lk_lockholder = LK_NOPROC;
|
|
lkp->lk_exclusivecount = 0;
|
|
} else {
|
|
lkp->lk_exclusivecount--;
|
|
}
|
|
} else if (lkp->lk_flags & LK_SHARE_NONZERO)
|
|
shareunlock(td, lkp, 1);
|
|
if (lkp->lk_flags & LK_WAIT_NONZERO)
|
|
wakeup((void *)lkp);
|
|
break;
|
|
|
|
case LK_DRAIN:
|
|
/*
|
|
* Check that we do not already hold the lock, as it can
|
|
* never drain if we do. Unfortunately, we have no way to
|
|
* check for holding a shared lock, but at least we can
|
|
* check for an exclusive one.
|
|
*/
|
|
if (lkp->lk_lockholder == thr)
|
|
panic("lockmgr: draining against myself");
|
|
|
|
error = acquiredrain(lkp, extflags);
|
|
if (error)
|
|
break;
|
|
lkp->lk_flags |= LK_DRAINING | LK_HAVE_EXCL;
|
|
lkp->lk_lockholder = thr;
|
|
lkp->lk_exclusivecount = 1;
|
|
COUNT(td, 1);
|
|
#if defined(DEBUG_LOCKS)
|
|
lkp->lk_filename = file;
|
|
lkp->lk_lineno = line;
|
|
lkp->lk_lockername = name;
|
|
#endif
|
|
break;
|
|
|
|
default:
|
|
mtx_unlock(lkp->lk_interlock);
|
|
panic("lockmgr: unknown locktype request %d",
|
|
flags & LK_TYPE_MASK);
|
|
/* NOTREACHED */
|
|
}
|
|
if ((lkp->lk_flags & LK_WAITDRAIN) &&
|
|
(lkp->lk_flags & (LK_HAVE_EXCL | LK_WANT_EXCL | LK_WANT_UPGRADE |
|
|
LK_SHARE_NONZERO | LK_WAIT_NONZERO)) == 0) {
|
|
lkp->lk_flags &= ~LK_WAITDRAIN;
|
|
wakeup((void *)&lkp->lk_flags);
|
|
}
|
|
mtx_unlock(lkp->lk_interlock);
|
|
return (error);
|
|
}
|
|
|
|
static int
|
|
acquiredrain(struct lock *lkp, int extflags) {
|
|
int error;
|
|
|
|
if ((extflags & LK_NOWAIT) && (lkp->lk_flags & LK_ALL)) {
|
|
return EBUSY;
|
|
}
|
|
while (lkp->lk_flags & LK_ALL) {
|
|
lkp->lk_flags |= LK_WAITDRAIN;
|
|
error = msleep(&lkp->lk_flags, lkp->lk_interlock, lkp->lk_prio,
|
|
lkp->lk_wmesg,
|
|
((extflags & LK_TIMELOCK) ? lkp->lk_timo : 0));
|
|
if (error)
|
|
return error;
|
|
if (extflags & LK_SLEEPFAIL) {
|
|
return ENOLCK;
|
|
}
|
|
}
|
|
return 0;
|
|
}
|
|
|
|
/*
|
|
* Transfer any waiting processes from one lock to another.
|
|
*/
|
|
void
|
|
transferlockers(from, to)
|
|
struct lock *from;
|
|
struct lock *to;
|
|
{
|
|
|
|
KASSERT(from != to, ("lock transfer to self"));
|
|
KASSERT((from->lk_flags&LK_WAITDRAIN) == 0, ("transfer draining lock"));
|
|
|
|
mtx_lock(from->lk_interlock);
|
|
if (from->lk_waitcount == 0) {
|
|
mtx_unlock(from->lk_interlock);
|
|
return;
|
|
}
|
|
from->lk_newlock = to;
|
|
wakeup((void *)from);
|
|
msleep(&from->lk_newlock, from->lk_interlock, from->lk_prio,
|
|
"lkxfer", 0);
|
|
from->lk_newlock = NULL;
|
|
from->lk_flags &= ~(LK_WANT_EXCL | LK_WANT_UPGRADE);
|
|
KASSERT(from->lk_waitcount == 0, ("active lock"));
|
|
mtx_unlock(from->lk_interlock);
|
|
}
|
|
|
|
|
|
/*
|
|
* Initialize a lock; required before use.
|
|
*/
|
|
void
|
|
lockinit(lkp, prio, wmesg, timo, flags)
|
|
struct lock *lkp;
|
|
int prio;
|
|
const char *wmesg;
|
|
int timo;
|
|
int flags;
|
|
{
|
|
CTR5(KTR_LOCK, "lockinit(): lkp == %p, prio == %d, wmesg == \"%s\", "
|
|
"timo == %d, flags = 0x%x\n", lkp, prio, wmesg, timo, flags);
|
|
|
|
lkp->lk_interlock = mtx_pool_alloc(mtxpool_lockbuilder);
|
|
lkp->lk_flags = (flags & LK_EXTFLG_MASK);
|
|
lkp->lk_sharecount = 0;
|
|
lkp->lk_waitcount = 0;
|
|
lkp->lk_exclusivecount = 0;
|
|
lkp->lk_prio = prio;
|
|
lkp->lk_wmesg = wmesg;
|
|
lkp->lk_timo = timo;
|
|
lkp->lk_lockholder = LK_NOPROC;
|
|
lkp->lk_newlock = NULL;
|
|
#ifdef DEBUG_LOCKS
|
|
lkp->lk_filename = "none";
|
|
lkp->lk_lockername = "never exclusive locked";
|
|
lkp->lk_lineno = 0;
|
|
lkp->lk_slockholder = LK_NOPROC;
|
|
lkp->lk_sfilename = "none";
|
|
lkp->lk_slockername = "never share locked";
|
|
lkp->lk_slineno = 0;
|
|
#endif
|
|
}
|
|
|
|
/*
|
|
* Destroy a lock.
|
|
*/
|
|
void
|
|
lockdestroy(lkp)
|
|
struct lock *lkp;
|
|
{
|
|
CTR2(KTR_LOCK, "lockdestroy(): lkp == %p (lk_wmesg == \"%s\")",
|
|
lkp, lkp->lk_wmesg);
|
|
}
|
|
|
|
/*
|
|
* Determine the status of a lock.
|
|
*/
|
|
int
|
|
lockstatus(lkp, td)
|
|
struct lock *lkp;
|
|
struct thread *td;
|
|
{
|
|
int lock_type = 0;
|
|
|
|
mtx_lock(lkp->lk_interlock);
|
|
if (lkp->lk_exclusivecount != 0) {
|
|
if (td == NULL || lkp->lk_lockholder == td)
|
|
lock_type = LK_EXCLUSIVE;
|
|
else
|
|
lock_type = LK_EXCLOTHER;
|
|
} else if (lkp->lk_sharecount != 0)
|
|
lock_type = LK_SHARED;
|
|
mtx_unlock(lkp->lk_interlock);
|
|
return (lock_type);
|
|
}
|
|
|
|
/*
|
|
* Determine the number of holders of a lock.
|
|
*/
|
|
int
|
|
lockcount(lkp)
|
|
struct lock *lkp;
|
|
{
|
|
int count;
|
|
|
|
mtx_lock(lkp->lk_interlock);
|
|
count = lkp->lk_exclusivecount + lkp->lk_sharecount;
|
|
mtx_unlock(lkp->lk_interlock);
|
|
return (count);
|
|
}
|
|
|
|
/*
|
|
* Print out information about state of a lock. Used by VOP_PRINT
|
|
* routines to display status about contained locks.
|
|
*/
|
|
void
|
|
lockmgr_printinfo(lkp)
|
|
struct lock *lkp;
|
|
{
|
|
|
|
if (lkp->lk_sharecount)
|
|
printf(" lock type %s: SHARED (count %d)", lkp->lk_wmesg,
|
|
lkp->lk_sharecount);
|
|
else if (lkp->lk_flags & LK_HAVE_EXCL)
|
|
printf(" lock type %s: EXCL (count %d) by thread %p (pid %d)",
|
|
lkp->lk_wmesg, lkp->lk_exclusivecount,
|
|
lkp->lk_lockholder, lkp->lk_lockholder->td_proc->p_pid);
|
|
if (lkp->lk_waitcount > 0)
|
|
printf(" with %d pending", lkp->lk_waitcount);
|
|
}
|