From 4820f9268d3dc1f2aac923de0a591ffd5d54ea89 Mon Sep 17 00:00:00 2001 From: Rich Felker Date: Tue, 8 Mar 2011 03:41:05 -0500 Subject: fix and optimize non-default-type mutex behavior problem 1: mutex type from the attribute was being ignored by pthread_mutex_init, so recursive/errorchecking mutexes were never being used at all. problem 2: ownership of recursive mutexes was not being enforced at unlock time. --- src/internal/pthread_impl.h | 1 + src/thread/pthread_mutex_init.c | 3 +-- src/thread/pthread_mutex_trylock.c | 27 ++++++++++++--------------- src/thread/pthread_mutex_unlock.c | 13 +++++-------- 4 files changed, 19 insertions(+), 25 deletions(-) (limited to 'src') diff --git a/src/internal/pthread_impl.h b/src/internal/pthread_impl.h index 22ba8b76..adb80f2f 100644 --- a/src/internal/pthread_impl.h +++ b/src/internal/pthread_impl.h @@ -47,6 +47,7 @@ struct pthread { #define _m_lock __u.__i[1] #define _m_waiters __u.__i[2] #define _m_owner __u.__i[3] +#define _m_count __u.__i[4] #define _c_block __u.__i[0] #define _c_clock __u.__i[1] #define _rw_wrlock __u.__i[0] diff --git a/src/thread/pthread_mutex_init.c b/src/thread/pthread_mutex_init.c index d453543d..6e23df13 100644 --- a/src/thread/pthread_mutex_init.c +++ b/src/thread/pthread_mutex_init.c @@ -3,7 +3,6 @@ int pthread_mutex_init(pthread_mutex_t *m, const pthread_mutexattr_t *a) { memset(m, 0, sizeof *m); - if (a) { - } + if (a) m->_m_type = *a & 3; return 0; } diff --git a/src/thread/pthread_mutex_trylock.c b/src/thread/pthread_mutex_trylock.c index 29268fdb..7ff4f703 100644 --- a/src/thread/pthread_mutex_trylock.c +++ b/src/thread/pthread_mutex_trylock.c @@ -2,27 +2,24 @@ int pthread_mutex_trylock(pthread_mutex_t *m) { - if (m->_m_type == PTHREAD_MUTEX_RECURSIVE) { - pthread_t self = pthread_self(); - if (m->_m_owner == self->tid) { - if ((unsigned)m->_m_lock >= INT_MAX) return EAGAIN; - a_inc(&m->_m_lock); + pthread_t self; + if (m->_m_type != PTHREAD_MUTEX_NORMAL) { + self = pthread_self(); + if (m->_m_type == PTHREAD_MUTEX_RECURSIVE + && m->_m_owner == self->tid) { + if ((unsigned)m->_m_count >= INT_MAX) return EAGAIN; + m->_m_count++; return 0; } - if (a_fetch_add(&m->_m_lock, 1)) { - if (a_fetch_add(&m->_m_lock, -1)==1 && m->_m_waiters) - __wake(&m->_m_lock, 1, 0); - return EBUSY; - } - m->_m_owner = self->tid; - return 0; } if (a_xchg(&m->_m_lock, 1)) if (m->_m_type == PTHREAD_MUTEX_ERRORCHECK - && m->_m_owner == pthread_self()->tid) return EDEADLK; + && m->_m_owner == self->tid) return EDEADLK; else return EBUSY; - if (m->_m_type == PTHREAD_MUTEX_ERRORCHECK) - m->_m_owner = pthread_self()->tid; + if (m->_m_type != PTHREAD_MUTEX_NORMAL) { + m->_m_owner = self->tid; + m->_m_count = 1; + } return 0; } diff --git a/src/thread/pthread_mutex_unlock.c b/src/thread/pthread_mutex_unlock.c index 0275eb52..39cea4b6 100644 --- a/src/thread/pthread_mutex_unlock.c +++ b/src/thread/pthread_mutex_unlock.c @@ -2,16 +2,13 @@ int pthread_mutex_unlock(pthread_mutex_t *m) { - if (m->_m_type == PTHREAD_MUTEX_RECURSIVE) { - if (a_fetch_add(&m->_m_lock, -1)==1 && m->_m_waiters) - __wake(&m->_m_lock, 1, 0); - return 0; + if (m->_m_type != PTHREAD_MUTEX_NORMAL) { + if (m->_m_owner != pthread_self()->tid) + return EPERM; + if (m->_m_type == PTHREAD_MUTEX_RECURSIVE && --m->_m_count) + return 0; } - if (m->_m_type == PTHREAD_MUTEX_ERRORCHECK - && m->_m_owner != pthread_self()->tid) - return EPERM; - m->_m_owner = 0; m->_m_lock = 0; if (m->_m_waiters) __wake(&m->_m_lock, 1, 0); -- cgit v1.2.1