diff options
author | jasone <jasone@FreeBSD.org> | 2000-06-14 17:17:41 +0000 |
---|---|---|
committer | jasone <jasone@FreeBSD.org> | 2000-06-14 17:17:41 +0000 |
commit | 9f479e9f39861a77981b3e6234e796caa25cfe0f (patch) | |
tree | 25b4c819ee7794359e6c426e91cd15c2c56a2f49 /lib/libc_r | |
parent | cc22f14b179a55f7686e798febd938bfef76c982 (diff) | |
download | FreeBSD-src-9f479e9f39861a77981b3e6234e796caa25cfe0f.zip FreeBSD-src-9f479e9f39861a77981b3e6234e796caa25cfe0f.tar.gz |
pthread_mutex_lock(), pthread_cond_trywait(), and pthread_cond_wait() are
not allowed to return EINTR, but use of pthread_suspend_np() could cause
EINTR to be returned. To fix this, restructure pthread_suspend_np() so that
it does not interrupt a thread that is waiting on a mutex or condition, and
keep enough state around that pthread_resume_np() can fix things up
afterwards.
Reviewed by: deischen
Diffstat (limited to 'lib/libc_r')
-rw-r--r-- | lib/libc_r/uthread/pthread_private.h | 13 | ||||
-rw-r--r-- | lib/libc_r/uthread/uthread_cancel.c | 23 | ||||
-rw-r--r-- | lib/libc_r/uthread/uthread_cond.c | 28 | ||||
-rw-r--r-- | lib/libc_r/uthread/uthread_mutex.c | 52 | ||||
-rw-r--r-- | lib/libc_r/uthread/uthread_resume_np.c | 31 | ||||
-rw-r--r-- | lib/libc_r/uthread/uthread_suspend_np.c | 14 |
6 files changed, 125 insertions, 36 deletions
diff --git a/lib/libc_r/uthread/pthread_private.h b/lib/libc_r/uthread/pthread_private.h index a86cfc6..6b48f23 100644 --- a/lib/libc_r/uthread/pthread_private.h +++ b/lib/libc_r/uthread/pthread_private.h @@ -350,6 +350,17 @@ struct pthread_attr { #define PTHREAD_CREATE_SUSPENDED 1 /* + * Additional state for a thread suspended with pthread_suspend_np(). + */ +enum pthread_susp { + SUSP_NO, /* Not suspended. */ + SUSP_YES, /* Suspended. */ + SUSP_NOWAIT, /* Suspended, was in a mutex or condition queue. */ + SUSP_MUTEX_WAIT,/* Suspended, still in a mutex queue. */ + SUSP_COND_WAIT /* Suspended, still in a condition queue. */ +}; + +/* * Miscellaneous definitions. */ #define PTHREAD_STACK_DEFAULT 65536 @@ -577,7 +588,7 @@ struct pthread { #define PTHREAD_CANCEL_NEEDED 0x0010 int cancelflags; - int suspended; + enum pthread_susp suspended; thread_continuation_t continuation; diff --git a/lib/libc_r/uthread/uthread_cancel.c b/lib/libc_r/uthread/uthread_cancel.c index 82ddbb8..c6df52e 100644 --- a/lib/libc_r/uthread/uthread_cancel.c +++ b/lib/libc_r/uthread/uthread_cancel.c @@ -37,15 +37,6 @@ pthread_cancel(pthread_t pthread) pthread->cancelflags |= PTHREAD_CANCELLING; break; - case PS_SUSPENDED: - /* - * This thread isn't in any scheduling - * queues; just change it's state: - */ - pthread->cancelflags |= PTHREAD_CANCELLING; - PTHREAD_SET_STATE(pthread, PS_RUNNING); - break; - case PS_SPINBLOCK: case PS_FDR_WAIT: case PS_FDW_WAIT: @@ -67,6 +58,20 @@ pthread_cancel(pthread_t pthread) PTHREAD_NEW_STATE(pthread,PS_RUNNING); break; + case PS_SUSPENDED: + if (pthread->suspended == SUSP_NO || + pthread->suspended == SUSP_YES || + pthread->suspended == SUSP_NOWAIT) { + /* + * This thread isn't in any scheduling + * queues; just change it's state: + */ + pthread->cancelflags |= + PTHREAD_CANCELLING; + PTHREAD_SET_STATE(pthread, PS_RUNNING); + break; + } + /* FALLTHROUGH */ case PS_MUTEX_WAIT: case PS_COND_WAIT: case PS_FDLR_WAIT: diff --git a/lib/libc_r/uthread/uthread_cond.c b/lib/libc_r/uthread/uthread_cond.c index 78ee042..49062be 100644 --- a/lib/libc_r/uthread/uthread_cond.c +++ b/lib/libc_r/uthread/uthread_cond.c @@ -285,7 +285,6 @@ pthread_cond_wait(pthread_cond_t * cond, pthread_mutex_t * mutex) if (interrupted != 0) { if (_thread_run->continuation != NULL) _thread_run->continuation((void *) _thread_run); - rval = EINTR; } _thread_leave_cancellation_point(); @@ -455,7 +454,6 @@ pthread_cond_timedwait(pthread_cond_t * cond, pthread_mutex_t * mutex, if (interrupted != 0) { if (_thread_run->continuation != NULL) _thread_run->continuation((void *) _thread_run); - rval = EINTR; } _thread_leave_cancellation_point(); @@ -489,9 +487,18 @@ pthread_cond_signal(pthread_cond_t * cond) switch ((*cond)->c_type) { /* Fast condition variable: */ case COND_TYPE_FAST: - if ((pthread = cond_queue_deq(*cond)) != NULL) - /* Allow the thread to run: */ - PTHREAD_NEW_STATE(pthread,PS_RUNNING); + if ((pthread = cond_queue_deq(*cond)) != NULL) { + /* + * Unless the thread is currently suspended, + * allow it to run. If the thread is suspended, + * make a note that the thread isn't in a wait + * queue any more. + */ + if (pthread->state != PS_SUSPENDED) + PTHREAD_NEW_STATE(pthread,PS_RUNNING); + else + pthread->suspended = SUSP_NOWAIT; + } /* Check for no more waiters: */ if (TAILQ_FIRST(&(*cond)->c_queue) == NULL) @@ -546,7 +553,16 @@ pthread_cond_broadcast(pthread_cond_t * cond) * condition queue: */ while ((pthread = cond_queue_deq(*cond)) != NULL) { - PTHREAD_NEW_STATE(pthread,PS_RUNNING); + /* + * Unless the thread is currently suspended, + * allow it to run. If the thread is suspended, + * make a note that the thread isn't in a wait + * queue any more. + */ + if (pthread->state != PS_SUSPENDED) + PTHREAD_NEW_STATE(pthread,PS_RUNNING); + else + pthread->suspended = SUSP_NOWAIT; } /* There are no more waiting threads: */ diff --git a/lib/libc_r/uthread/uthread_mutex.c b/lib/libc_r/uthread/uthread_mutex.c index c97c86b..12fdc8e 100644 --- a/lib/libc_r/uthread/uthread_mutex.c +++ b/lib/libc_r/uthread/uthread_mutex.c @@ -612,7 +612,6 @@ pthread_mutex_lock(pthread_mutex_t * mutex) */ if (_thread_run->interrupted != 0) { mutex_queue_remove(*mutex, _thread_run); - ret = EINTR; } /* Unlock the mutex structure: */ @@ -777,11 +776,20 @@ mutex_unlock_common(pthread_mutex_t * mutex, int add_reference) if (((*mutex)->m_owner = mutex_queue_deq(*mutex)) != NULL) { /* - * Allow the new owner of the mutex to - * run: + * Unless the new owner of the mutex is + * currently suspended, allow the owner + * to run. If the thread is suspended, + * make a note that the thread isn't in + * a wait queue any more. */ - PTHREAD_NEW_STATE((*mutex)->m_owner, - PS_RUNNING); + if (((*mutex)->m_owner->state != + PS_SUSPENDED)) { + PTHREAD_NEW_STATE((*mutex)->m_owner, + PS_RUNNING); + } else { + (*mutex)->m_owner->suspended = + SUSP_NOWAIT; + } /* * Add the mutex to the threads list of @@ -899,11 +907,20 @@ mutex_unlock_common(pthread_mutex_t * mutex, int add_reference) (*mutex)->m_prio; /* - * Allow the new owner of the mutex to - * run: + * Unless the new owner of the mutex is + * currently suspended, allow the owner + * to run. If the thread is suspended, + * make a note that the thread isn't in + * a wait queue any more. */ - PTHREAD_NEW_STATE((*mutex)->m_owner, - PS_RUNNING); + if (((*mutex)->m_owner->state != + PS_SUSPENDED)) { + PTHREAD_NEW_STATE((*mutex)->m_owner, + PS_RUNNING); + } else { + (*mutex)->m_owner->suspended = + SUSP_NOWAIT; + } } } break; @@ -1019,11 +1036,20 @@ mutex_unlock_common(pthread_mutex_t * mutex, int add_reference) (*mutex)->m_prio; /* - * Allow the new owner of the mutex to - * run: + * Unless the new owner of the mutex is + * currently suspended, allow the owner + * to run. If the thread is suspended, + * make a note that the thread isn't in + * a wait queue any more. */ - PTHREAD_NEW_STATE((*mutex)->m_owner, - PS_RUNNING); + if (((*mutex)->m_owner->state != + PS_SUSPENDED)) { + PTHREAD_NEW_STATE((*mutex)->m_owner, + PS_RUNNING); + } else { + (*mutex)->m_owner->suspended = + SUSP_NOWAIT; + } } } break; diff --git a/lib/libc_r/uthread/uthread_resume_np.c b/lib/libc_r/uthread/uthread_resume_np.c index fae355a..32b3d05 100644 --- a/lib/libc_r/uthread/uthread_resume_np.c +++ b/lib/libc_r/uthread/uthread_resume_np.c @@ -40,12 +40,14 @@ int pthread_resume_np(pthread_t thread) { - int ret; + int ret; + enum pthread_susp old_suspended; /* Find the thread in the list of active threads: */ if ((ret = _find_thread(thread)) == 0) { /* Cancel any pending suspensions: */ - thread->suspended = 0; + old_suspended = thread->suspended; + thread->suspended = SUSP_NO; /* Is it currently suspended? */ if (thread->state == PS_SUSPENDED) { @@ -55,9 +57,28 @@ pthread_resume_np(pthread_t thread) */ _thread_kern_sig_defer(); - /* Allow the thread to run. */ - PTHREAD_SET_STATE(thread,PS_RUNNING); - PTHREAD_PRIOQ_INSERT_TAIL(thread); + switch (old_suspended) { + case SUSP_MUTEX_WAIT: + /* Set the thread's state back. */ + PTHREAD_SET_STATE(thread,PS_MUTEX_WAIT); + break; + case SUSP_COND_WAIT: + /* Set the thread's state back. */ + PTHREAD_SET_STATE(thread,PS_COND_WAIT); + break; + case SUSP_NOWAIT: + /* Allow the thread to run. */ + PTHREAD_SET_STATE(thread,PS_RUNNING); + PTHREAD_WAITQ_REMOVE(thread); + PTHREAD_PRIOQ_INSERT_TAIL(thread); + break; + case SUSP_NO: + case SUSP_YES: + /* Allow the thread to run. */ + PTHREAD_SET_STATE(thread,PS_RUNNING); + PTHREAD_PRIOQ_INSERT_TAIL(thread); + break; + } /* * Undefer and handle pending signals, yielding if diff --git a/lib/libc_r/uthread/uthread_suspend_np.c b/lib/libc_r/uthread/uthread_suspend_np.c index 9b08115..083f552 100644 --- a/lib/libc_r/uthread/uthread_suspend_np.c +++ b/lib/libc_r/uthread/uthread_suspend_np.c @@ -91,13 +91,23 @@ pthread_suspend_np(pthread_t thread) break; case PS_MUTEX_WAIT: + /* Mark the thread as suspended and still in a queue. */ + thread->suspended = SUSP_MUTEX_WAIT; + + PTHREAD_SET_STATE(thread, PS_SUSPENDED); + break; case PS_COND_WAIT: + /* Mark the thread as suspended and still in a queue. */ + thread->suspended = SUSP_COND_WAIT; + + PTHREAD_SET_STATE(thread, PS_SUSPENDED); + break; case PS_FDLR_WAIT: case PS_FDLW_WAIT: case PS_FILE_WAIT: case PS_JOIN: /* Mark the thread as suspended: */ - thread->suspended = 1; + thread->suspended = SUSP_YES; /* * Threads in these states may be in queues. @@ -134,7 +144,7 @@ pthread_suspend_np(pthread_t thread) static void finish_suspension(void *arg) { - if (_thread_run->suspended != 0) + if (_thread_run->suspended != SUSP_NO) _thread_kern_sched_state(PS_SUSPENDED, __FILE__, __LINE__); } |