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fix and optimize non-default-type mutex behavior

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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.
This commit is contained in:
Rich Felker
2011-03-08 03:41:05 -05:00
parent 1d6b1f1592
commit 4820f9268d
4 changed files with 19 additions and 25 deletions
Download Patch File Download Diff File Expand all files Collapse all files

1
src/internal/pthread_impl.h
View File

@ -47,6 +47,7 @@ struct pthread {
#define _m_lock __u.__i[1] #define _m_lock __u.__i[1]
#define _m_waiters __u.__i[2] #define _m_waiters __u.__i[2]
#define _m_owner __u.__i[3] #define _m_owner __u.__i[3]
#define _m_count __u.__i[4]
#define _c_block __u.__i[0] #define _c_block __u.__i[0]
#define _c_clock __u.__i[1] #define _c_clock __u.__i[1]
#define _rw_wrlock __u.__i[0] #define _rw_wrlock __u.__i[0]

3
src/thread/pthread_mutex_init.c
View File

@ -3,7 +3,6 @@
int pthread_mutex_init(pthread_mutex_t *m, const pthread_mutexattr_t *a) int pthread_mutex_init(pthread_mutex_t *m, const pthread_mutexattr_t *a)
{ {
memset(m, 0, sizeof *m); memset(m, 0, sizeof *m);
if (a) { if (a) m->_m_type = *a & 3;
}
return 0; return 0;
} }

27
src/thread/pthread_mutex_trylock.c
View File

@ -2,27 +2,24 @@
int pthread_mutex_trylock(pthread_mutex_t *m) int pthread_mutex_trylock(pthread_mutex_t *m)
{ {
if (m->_m_type == PTHREAD_MUTEX_RECURSIVE) { pthread_t self;
pthread_t self = pthread_self(); if (m->_m_type != PTHREAD_MUTEX_NORMAL) {
if (m->_m_owner == self->tid) { self = pthread_self();
if ((unsigned)m->_m_lock >= INT_MAX) return EAGAIN; if (m->_m_type == PTHREAD_MUTEX_RECURSIVE
a_inc(&m->_m_lock); && m->_m_owner == self->tid) {
if ((unsigned)m->_m_count >= INT_MAX) return EAGAIN;
m->_m_count++;
return 0; 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 (a_xchg(&m->_m_lock, 1))
if (m->_m_type == PTHREAD_MUTEX_ERRORCHECK 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; else return EBUSY;
if (m->_m_type == PTHREAD_MUTEX_ERRORCHECK) if (m->_m_type != PTHREAD_MUTEX_NORMAL) {
m->_m_owner = pthread_self()->tid; m->_m_owner = self->tid;
m->_m_count = 1;
}
return 0; return 0;
} }

13
src/thread/pthread_mutex_unlock.c
View File

@ -2,16 +2,13 @@
int pthread_mutex_unlock(pthread_mutex_t *m) int pthread_mutex_unlock(pthread_mutex_t *m)
{ {
if (m->_m_type == PTHREAD_MUTEX_RECURSIVE) { if (m->_m_type != PTHREAD_MUTEX_NORMAL) {
if (a_fetch_add(&m->_m_lock, -1)==1 && m->_m_waiters) if (m->_m_owner != pthread_self()->tid)
__wake(&m->_m_lock, 1, 0); return EPERM;
return 0; 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_owner = 0;
m->_m_lock = 0; m->_m_lock = 0;
if (m->_m_waiters) __wake(&m->_m_lock, 1, 0); if (m->_m_waiters) __wake(&m->_m_lock, 1, 0);