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authorRich Felker <dalias@aerifal.cx>2011-03-08 03:41:05 -0500
committerRich Felker <dalias@aerifal.cx>2011-03-08 03:41:05 -0500
commit4820f9268d3dc1f2aac923de0a591ffd5d54ea89 (patch)
treeb0b247a81d43cb7a23a5eb0dc33ea1c83c9130d4
parent1d6b1f15929ff19f4dce4f83947e14f7c3fc3c19 (diff)
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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.
-rw-r--r--src/internal/pthread_impl.h1
-rw-r--r--src/thread/pthread_mutex_init.c3
-rw-r--r--src/thread/pthread_mutex_trylock.c27
-rw-r--r--src/thread/pthread_mutex_unlock.c13
4 files changed, 19 insertions, 25 deletions
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);