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// -*- mode:C++; tab-width:8; c-basic-offset:2; indent-tabs-mode:t -*-
// vim: ts=8 sw=2 smarttab
/*
* Ceph - scalable distributed file system
*
* Copyright (C) 2004-2006 Sage Weil <sage@newdream.net>
*
* This is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License version 2.1, as published by the Free Software
* Foundation. See file COPYING.
*
*/
#include "common/Mutex.h"
#include "common/config.h"
#include "common/Clock.h"
#include "common/valgrind.h"
Mutex::Mutex(const std::string &n, bool r, bool ld,
bool bt) :
name(n), id(-1), recursive(r), lockdep(ld), backtrace(bt), nlock(0),
locked_by(0)
{
ANNOTATE_BENIGN_RACE_SIZED(&id, sizeof(id), "Mutex lockdep id");
ANNOTATE_BENIGN_RACE_SIZED(&nlock, sizeof(nlock), "Mutex nlock");
ANNOTATE_BENIGN_RACE_SIZED(&locked_by, sizeof(locked_by), "Mutex locked_by");
if (recursive) {
// Mutexes of type PTHREAD_MUTEX_RECURSIVE do all the same checks as
// mutexes of type PTHREAD_MUTEX_ERRORCHECK.
pthread_mutexattr_t attr;
pthread_mutexattr_init(&attr);
pthread_mutexattr_settype(&attr, PTHREAD_MUTEX_RECURSIVE);
pthread_mutex_init(&_m,&attr);
pthread_mutexattr_destroy(&attr);
if (lockdep && g_lockdep)
_register();
}
else if (lockdep) {
// If the mutex type is PTHREAD_MUTEX_ERRORCHECK, then error checking
// shall be provided. If a thread attempts to relock a mutex that it
// has already locked, an error shall be returned. If a thread
// attempts to unlock a mutex that it has not locked or a mutex which
// is unlocked, an error shall be returned.
pthread_mutexattr_t attr;
pthread_mutexattr_init(&attr);
pthread_mutexattr_settype(&attr, PTHREAD_MUTEX_ERRORCHECK);
pthread_mutex_init(&_m, &attr);
pthread_mutexattr_destroy(&attr);
if (g_lockdep)
_register();
}
else {
// If the mutex type is PTHREAD_MUTEX_DEFAULT, attempting to recursively
// lock the mutex results in undefined behavior. Attempting to unlock the
// mutex if it was not locked by the calling thread results in undefined
// behavior. Attempting to unlock the mutex if it is not locked results in
// undefined behavior.
pthread_mutex_init(&_m, NULL);
}
}
Mutex::~Mutex() {
ceph_assert(nlock == 0);
// helgrind gets confused by condition wakeups leading to mutex destruction
ANNOTATE_BENIGN_RACE_SIZED(&_m, sizeof(_m), "Mutex primitive");
pthread_mutex_destroy(&_m);
if (lockdep && g_lockdep) {
lockdep_unregister(id);
}
}
void Mutex::lock(bool no_lockdep)
{
if (lockdep && g_lockdep && !no_lockdep && !recursive) _will_lock();
int r = pthread_mutex_lock(&_m);
ceph_assert(r == 0);
if (lockdep && g_lockdep) _locked();
_post_lock();
}
void Mutex::unlock()
{
_pre_unlock();
if (lockdep && g_lockdep) _will_unlock();
int r = pthread_mutex_unlock(&_m);
ceph_assert(r == 0);
}
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