diff --git a/src/platform/posix/posix_pollq_port.c b/src/platform/posix/posix_pollq_port.c
index 49658f3bf..2e3debad7 100644
--- a/src/platform/posix/posix_pollq_port.c
+++ b/src/platform/posix/posix_pollq_port.c
@@ -30,6 +30,8 @@
 typedef struct nni_posix_pollq {
 	int     port; // port id (from port_create)
 	nni_thr thr;  // worker thread
+	nni_mtx mtx;
+	nni_cv  cv;
 } nni_posix_pollq;
 
 // single global instance for now
@@ -45,15 +47,13 @@ nni_posix_pfd_init(nni_posix_pfd *pfdp, int fd, nni_posix_pfd_cb cb, void *arg)
 	(void) fcntl(fd, F_SETFD, FD_CLOEXEC);
 	(void) fcntl(fd, F_SETFL, O_NONBLOCK);
 
-	nni_mtx_init(&pfd->mtx);
-	nni_cv_init(&pfd->cv, &pfd->mtx);
-	pfd->closed  = false;
-	pfd->closing = false;
-	pfd->fd      = fd;
-	pfd->pq      = pq;
-	pfd->cb      = cb;
-	pfd->arg     = arg;
-	pfd->data    = NULL;
+	nni_atomic_init(&pfd->events);
+	pfd->closed = false;
+	pfd->fd     = fd;
+	pfd->pq     = pq;
+	pfd->cb     = cb;
+	pfd->arg    = arg;
+	pfd->data   = NULL;
 }
 
 int
@@ -71,13 +71,8 @@ nni_posix_pfd_close(nni_posix_pfd *pfd)
 		return;
 	}
 
-	nni_mtx_lock(&pfd->mtx);
-	if (!pfd->closing) {
-		pfd->closing = true;
-		(void) shutdown(pfd->fd, SHUT_RDWR);
-		port_dissociate(pq->port, PORT_SOURCE_FD, pfd->fd);
-	}
-	nni_mtx_unlock(&pfd->mtx);
+	(void) shutdown(pfd->fd, SHUT_RDWR);
+	port_dissociate(pq->port, PORT_SOURCE_FD, pfd->fd);
 
 	// Send the wake event to the poller to synchronize with it.
 	// Note that port_send should only really fail if out of memory
@@ -102,11 +97,11 @@ nni_posix_pfd_stop(nni_posix_pfd *pfd)
 		}
 		sched_yield(); // try again later...
 	}
-	nni_mtx_lock(&pfd->mtx);
+	nni_mtx_lock(&pq->mtx);
 	while (!pfd->closed) {
-		nni_cv_wait(&pfd->cv);
+		nni_cv_wait(&pq->cv);
 	}
-	nni_mtx_unlock(&pfd->mtx);
+	nni_mtx_unlock(&pq->mtx);
 }
 
 void
@@ -122,27 +117,21 @@ nni_posix_pfd_fini(nni_posix_pfd *pfd)
 
 	// We're exclusive now.
 	(void) close(pfd->fd);
-	nni_cv_fini(&pfd->cv);
-	nni_mtx_fini(&pfd->mtx);
 }
 
 int
 nni_posix_pfd_arm(nni_posix_pfd *pfd, unsigned events)
 {
 	nni_posix_pollq *pq = pfd->pq;
+	int              rv;
+	int              ev = (int) events;
 
-	nni_mtx_lock(&pfd->mtx);
-	if (!pfd->closing) {
-		pfd->events |= events;
-		if (port_associate(pq->port, PORT_SOURCE_FD, pfd->fd,
-		        (int) pfd->events, pfd) != 0) {
-			int rv = nni_plat_errno(errno);
-			nni_mtx_unlock(&pfd->mtx);
-			return (rv);
-		}
+	ev |= ni_atomic_or(&pfd->events, ev);
+	rv = port_associate(pq->port, PORT_SOURCE_FD, pfd->fd, ev, pfd);
+	if (rv != 0) {
+		nni_plat_errno(errno);
 	}
-	nni_mtx_unlock(&pfd->mtx);
-	return (0);
+	return (rv);
 }
 
 static void
@@ -152,7 +141,7 @@ nni_posix_poll_thr(void *arg)
 		nni_posix_pollq *pq = arg;
 		port_event_t     ev[NNI_MAX_PORTEV];
 		nni_posix_pfd   *pfd;
-		unsigned         events;
+		int              events;
 		nni_posix_pfd_cb cb;
 		void            *arg;
 		unsigned         n;
@@ -168,40 +157,35 @@ nni_posix_poll_thr(void *arg)
 		// We run through the returned ports twice.  First we
 		// get the callbacks.  Then we do the reaps.  This way
 		// we ensure that we only reap *after* callbacks have run.
+		bool user_wake = false;
 		for (unsigned i = 0; i < n; i++) {
-			if (ev[i].portev_source != PORT_SOURCE_FD) {
+			switch (ev[i].portev_source) {
+			case PORT_SOURCE_USER:
+				user_wake = true;
 				continue;
-			}
-			pfd    = ev[i].portev_user;
-			events = ev[i].portev_events;
-
-			nni_mtx_lock(&pfd->mtx);
-			cb  = pfd->cb;
-			arg = pfd->data;
-			pfd->events &= ~events;
-			nni_mtx_unlock(&pfd->mtx);
-
-			if (cb != NULL) {
-				cb(pfd, events, arg);
+			case PORT_SOURCE_FD:
+				if (ev[i].portev_source != PORT_SOURCE_FD) {
+					continue;
+				}
+				pfd    = ev[i].portev_user;
+				events = ev[i].portev_events;
+
+				cb  = pfd->cb;
+				arg = pfd->data;
+				nni_atomic_and(&pfd->events, ~events);
+
+				cb(pfd, (unsigned) events, arg);
 			}
 		}
-		for (unsigned i = 0; i < n; i++) {
-			if (ev[i].portev_source != PORT_SOURCE_USER) {
-				continue;
+		if (user_wake) {
+			nni_mtx_lock(&pq->mtx);
+			for (unsigned i = 0; i < n; i++) {
+				if (ev[i].portev_source == PORT_SOURCE_USER) {
+					pfd->closed = true;
+				}
 			}
-
-			// User event telling us to stop doing things.
-			// We signal back to use this as a coordination
-			// event between the pollq and the thread
-			// handler. NOTE: It is absolutely critical
-			// that there is only a single thread per
-			// pollq.  Otherwise we cannot be sure that we
-			// are blocked completely,
-			pfd = ev[i].portev_user;
-			nni_mtx_lock(&pfd->mtx);
-			pfd->closed = true;
-			nni_cv_wake(&pfd->cv);
-			nni_mtx_unlock(&pfd->mtx);
+			nni_cv_wake(&pq->cv);
+			nni_mtx_unlock(&pq->mtx);
 		}
 	}
 }
@@ -210,6 +194,8 @@ static void
 nni_posix_pollq_destroy(nni_posix_pollq *pq)
 {
 	(void) close(pq->port);
+	nni_cv_destroy(&pq->cv);
+	nni_mtx_fini(&pq->mtx);
 	nni_thr_fini(&pq->thr);
 }
 
@@ -228,6 +214,8 @@ nni_posix_pollq_create(nni_posix_pollq *pq)
 	}
 	nni_thr_set_name(&pq->thr, "nng:poll:port");
 
+	nni_mtx_init(&pq->mtx);
+	nni_cv_init(&pq->cv, pq->mtx);
 	nni_thr_run(&pq->thr);
 	return (0);
 }
diff --git a/src/platform/posix/posix_pollq_port.h b/src/platform/posix/posix_pollq_port.h
index cbeab6940..d8771527a 100644
--- a/src/platform/posix/posix_pollq_port.h
+++ b/src/platform/posix/posix_pollq_port.h
@@ -20,11 +20,8 @@ typedef struct nni_posix_pollq nni_posix_pollq;
 struct nni_posix_pfd {
 	nni_posix_pollq *pq;
 	int              fd;
-	nni_mtx          mtx;
-	nni_cv           cv;
-	unsigned         events;
+	nni_atomic_int   events;
 	bool             closed;
-	bool             closing;
 	nni_posix_pfd_cb cb;
 	void            *data;
 };