diff --git a/stream.c b/stream.c
index a795772..cf84193 100644
--- a/stream.c
+++ b/stream.c
@@ -67,7 +67,7 @@ static struct compress_thread{
 	uchar c_type;	/* Compression type */
 	i64 s_len;	/* Data length uncompressed */
 	i64 c_len;	/* Data length compressed */
-	pthread_mutex_t mutex; /* This thread's mutex */
+	cksem_t cksem;  /* This thread's semaphore */
 	struct stream_info *sinfo;
 	int streamno;
 	uchar salt[SALT_LEN];
@@ -898,14 +898,10 @@ bool prepare_streamout_threads(rzip_control *control)
 		fatal_return(("Unable to calloc cthread in prepare_streamout_threads\n"), false);
 	}
 
-	for (i = 0; i < control->threads; i++)
-		if (unlikely(!init_mutex(control, &cthread[i].mutex))) {
-			int x;
-			for (x = 0; x < i; x++) pthread_mutex_destroy(&cthread[x].mutex);
-			free(threads);
-			free(cthread);
-			return false;
-		}
+	for (i = 0; i < control->threads; i++) {
+		cksem_init(control, &cthread[i].cksem);
+		cksem_post(control, &cthread[i].cksem);
+	}
 	return true;
 }
 
@@ -917,13 +913,7 @@ bool close_streamout_threads(rzip_control *control)
 	/* Wait for the threads in the correct order in case they end up
 	 * serialised */
 	for (i = 0; i < control->threads; i++) {
-		if (unlikely(!lock_mutex(control, &cthread[close_thread].mutex))) {
-			int x;
-			for (x = 0; x < i; x++) unlock_mutex(control, &cthread[close_thread].mutex);
-			free(cthread);
-			free(threads);
-			return false;
-		}
+		cksem_wait(control, &cthread[close_thread].cksem);
 
 		if (++close_thread == control->threads)
 			close_thread = 0;
@@ -1440,7 +1430,7 @@ retry:
 	unlock_mutex(control, &output_lock);
 
 error:
-	unlock_mutex(control, &cti->mutex);
+	cksem_post(control, &cti->cksem);
 
 	return NULL;
 }
@@ -1451,7 +1441,7 @@ static bool clear_buffer(rzip_control *control, struct stream_info *sinfo, int s
 	stream_thread_struct *s;
 
 	/* Make sure this thread doesn't already exist */
-	lock_mutex(control, &cthread[i].mutex);
+	cksem_wait(control, &cthread[i].cksem);
 
 	cthread[i].sinfo = sinfo;
 	cthread[i].streamno = streamno;
@@ -1463,14 +1453,14 @@ static bool clear_buffer(rzip_control *control, struct stream_info *sinfo, int s
 
 	s = malloc(sizeof(stream_thread_struct));
 	if (unlikely(!s)) {
-		unlock_mutex(control, &cthread[i].mutex);
+		cksem_post(control, &cthread[i].cksem);
 		fatal_return(("Unable to malloc in clear_buffer"), false);
 	}
 	s->i = i;
 	s->control = control;
 	if (unlikely((!create_pthread(control, &threads[i], NULL, compthread, s)) ||
 	             (!detach_pthread(control, &threads[i])))) {
-		unlock_mutex(control, &cthread[i].mutex);
+		cksem_post(control, &cthread[i].cksem);
 		return false;
 	}
 
@@ -1480,7 +1470,7 @@ static bool clear_buffer(rzip_control *control, struct stream_info *sinfo, int s
 		 * new one. */
 		sinfo->s[streamno].buf = malloc(sinfo->bufsize);
 		if (unlikely(!sinfo->s[streamno].buf)) {
-			unlock_mutex(control, &cthread[i].mutex);
+			cksem_post(control, &cthread[i].cksem);
 			fatal_return(("Unable to malloc buffer of size %lld in flush_buffer\n", sinfo->bufsize), false);
 		}
 		sinfo->s[streamno].buflen = 0;
@@ -1770,8 +1760,8 @@ int close_stream_out(rzip_control *control, void *ss)
 		int close_thread = output_thread;
 
 		for (i = 0; i < control->threads; i++) {
-			lock_mutex(control, &cthread[close_thread].mutex);
-			unlock_mutex(control, &cthread[close_thread].mutex);
+			cksem_wait(control, &cthread[close_thread].cksem);
+			cksem_post(control, &cthread[close_thread].cksem);
 			if (++close_thread == control->threads)
 				close_thread = 0;
 		}