diff --git a/CHANGELOG.md b/CHANGELOG.md
index d9569097e..0a32f24b3 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -47,6 +47,12 @@ option, but instead returns SPDK_APP_PARSE_ARGS_HELP and
 SPDK_APP_PARSE_ARGS_FAIL, respectively, and SPDK_APP_PARSE_ARGS_SUCCESS
 on success.
 
+### I/O Channels
+
+The prototype for spdk_poller_fn() has been modified; it now returns a value indicating
+whether or not the poller did any work.  Existing pollers will need to be updated to
+return a value.
+
 ## v18.01: Blobstore Thin Provisioning
 
 ### Build System
diff --git a/include/spdk/io_channel.h b/include/spdk/io_channel.h
index 60d4005e2..7dc6be88c 100644
--- a/include/spdk/io_channel.h
+++ b/include/spdk/io_channel.h
@@ -54,7 +54,15 @@ typedef void (*spdk_thread_fn)(void *ctx);
 typedef void (*spdk_thread_pass_msg)(spdk_thread_fn fn, void *ctx,
 				     void *thread_ctx);
 
-typedef void (*spdk_poller_fn)(void *ctx);
+/**
+ * Callback function for a poller.
+ *
+ * \param ctx Context passed as arg to spdk_poller_register()
+ * \return 0 to indicate that polling took place but no events were found;
+ *         positive to indicate that polling took place and some events were processed;
+ *         negative if the poller does not provide spin-wait information.
+ */
+typedef int (*spdk_poller_fn)(void *ctx);
 typedef struct spdk_poller *(*spdk_start_poller)(void *thread_ctx,
 		spdk_poller_fn fn,
 		void *arg,
diff --git a/lib/bdev/aio/bdev_aio.c b/lib/bdev/aio/bdev_aio.c
index 9bc2ac2e8..1281c9a8f 100644
--- a/lib/bdev/aio/bdev_aio.c
+++ b/lib/bdev/aio/bdev_aio.c
@@ -209,7 +209,7 @@ bdev_aio_initialize_io_channel(struct bdev_aio_io_channel *ch)
 	return 0;
 }
 
-static void
+static int
 bdev_aio_poll(void *arg)
 {
 	struct bdev_aio_io_channel *ch = arg;
@@ -227,7 +227,7 @@ bdev_aio_poll(void *arg)
 
 	if (nr < 0) {
 		SPDK_ERRLOG("%s: io_getevents returned %d\n", __func__, nr);
-		return;
+		return -1;
 	}
 
 	for (i = 0; i < nr; i++) {
@@ -241,6 +241,8 @@ bdev_aio_poll(void *arg)
 		spdk_bdev_io_complete(spdk_bdev_io_from_ctx(aio_task), status);
 		ch->io_inflight--;
 	}
+
+	return nr;
 }
 
 static void
@@ -257,8 +259,7 @@ _bdev_aio_get_io_inflight(struct spdk_io_channel_iter *i)
 	spdk_for_each_channel_continue(i, 0);
 }
 
-static void
-bdev_aio_reset_retry_timer(void *arg);
+static int bdev_aio_reset_retry_timer(void *arg);
 
 static void
 _bdev_aio_get_io_inflight_done(struct spdk_io_channel_iter *i, int status)
@@ -273,7 +274,7 @@ _bdev_aio_get_io_inflight_done(struct spdk_io_channel_iter *i, int status)
 	spdk_bdev_io_complete(spdk_bdev_io_from_ctx(fdisk->reset_task), SPDK_BDEV_IO_STATUS_SUCCESS);
 }
 
-static void
+static int
 bdev_aio_reset_retry_timer(void *arg)
 {
 	struct file_disk *fdisk = arg;
@@ -286,6 +287,8 @@ bdev_aio_reset_retry_timer(void *arg)
 			      _bdev_aio_get_io_inflight,
 			      fdisk,
 			      _bdev_aio_get_io_inflight_done);
+
+	return -1;
 }
 
 static void
diff --git a/lib/bdev/bdev.c b/lib/bdev/bdev.c
index 174dad271..55ed33a3d 100644
--- a/lib/bdev/bdev.c
+++ b/lib/bdev/bdev.c
@@ -955,7 +955,7 @@ spdk_bdev_qos_get_max_ios_per_timeslice(struct spdk_bdev *bdev)
 			SPDK_BDEV_QOS_MIN_IO_PER_TIMESLICE);
 }
 
-static void
+static int
 spdk_bdev_channel_poll_qos(void *arg)
 {
 	struct spdk_bdev_channel	*ch = arg;
@@ -966,6 +966,8 @@ spdk_bdev_channel_poll_qos(void *arg)
 	spdk_bdev_qos_get_max_ios_per_timeslice(bdev);
 
 	_spdk_bdev_qos_io_submit(ch);
+
+	return -1;
 }
 
 static void
diff --git a/lib/bdev/null/bdev_null.c b/lib/bdev/null/bdev_null.c
index 9c7dab6fb..bdb3f0edd 100644
--- a/lib/bdev/null/bdev_null.c
+++ b/lib/bdev/null/bdev_null.c
@@ -192,7 +192,7 @@ create_null_bdev(const char *name, const struct spdk_uuid *uuid,
 	return &bdev->bdev;
 }
 
-static void
+static int
 null_io_poll(void *arg)
 {
 	struct null_io_channel		*ch = arg;
@@ -202,11 +202,17 @@ null_io_poll(void *arg)
 	TAILQ_INIT(&io);
 	TAILQ_SWAP(&ch->io, &io, spdk_bdev_io, module_link);
 
+	if (TAILQ_EMPTY(&io)) {
+		return 0;
+	}
+
 	while (!TAILQ_EMPTY(&io)) {
 		bdev_io = TAILQ_FIRST(&io);
 		TAILQ_REMOVE(&io, bdev_io, module_link);
 		spdk_bdev_io_complete(bdev_io, SPDK_BDEV_IO_STATUS_SUCCESS);
 	}
+
+	return 1;
 }
 
 static int
diff --git a/lib/bdev/nvme/bdev_nvme.c b/lib/bdev/nvme/bdev_nvme.c
index bc096b5fa..d733731b9 100644
--- a/lib/bdev/nvme/bdev_nvme.c
+++ b/lib/bdev/nvme/bdev_nvme.c
@@ -196,14 +196,14 @@ bdev_nvme_writev(struct nvme_bdev *nbdev, struct spdk_io_channel *ch,
 				   iov, iovcnt, lba_count, lba);
 }
 
-static void
+static int
 bdev_nvme_poll(void *arg)
 {
 	struct nvme_io_channel *ch = arg;
 	int32_t num_completions;
 
 	if (ch->qpair == NULL) {
-		return;
+		return -1;
 	}
 
 	if (ch->collect_spin_stat && ch->start_ticks == 0) {
@@ -223,14 +223,16 @@ bdev_nvme_poll(void *arg)
 			ch->end_ticks = spdk_get_ticks();
 		}
 	}
+
+	return num_completions;
 }
 
-static void
+static int
 bdev_nvme_poll_adminq(void *arg)
 {
 	struct spdk_nvme_ctrlr *ctrlr = arg;
 
-	spdk_nvme_ctrlr_process_admin_completions(ctrlr);
+	return spdk_nvme_ctrlr_process_admin_completions(ctrlr);
 }
 
 static void
@@ -880,12 +882,14 @@ remove_cb(void *cb_ctx, struct spdk_nvme_ctrlr *ctrlr)
 	pthread_mutex_unlock(&g_bdev_nvme_mutex);
 }
 
-static void
+static int
 bdev_nvme_hotplug(void *arg)
 {
 	if (spdk_nvme_probe(NULL, NULL, hotplug_probe_cb, attach_cb, remove_cb) != 0) {
 		SPDK_ERRLOG("spdk_nvme_probe() failed\n");
 	}
+
+	return -1;
 }
 
 int
diff --git a/lib/bdev/rbd/bdev_rbd.c b/lib/bdev/rbd/bdev_rbd.c
index beae99b3d..5927426f6 100644
--- a/lib/bdev/rbd/bdev_rbd.c
+++ b/lib/bdev/rbd/bdev_rbd.c
@@ -274,7 +274,7 @@ bdev_rbd_flush(struct bdev_rbd *disk, struct spdk_io_channel *ch,
 	return bdev_rbd_start_aio(rbdio_ch->image, bdev_io, NULL, offset, nbytes);
 }
 
-static void
+static int
 bdev_rbd_reset_timer(void *arg)
 {
 	struct bdev_rbd *disk = arg;
@@ -286,6 +286,8 @@ bdev_rbd_reset_timer(void *arg)
 	spdk_bdev_io_complete(disk->reset_bdev_io, SPDK_BDEV_IO_STATUS_SUCCESS);
 	spdk_poller_unregister(&disk->reset_timer);
 	disk->reset_bdev_io = NULL;
+
+	return -1;
 }
 
 static int
@@ -384,7 +386,7 @@ bdev_rbd_io_type_supported(void *ctx, enum spdk_bdev_io_type io_type)
 	}
 }
 
-static void
+static int
 bdev_rbd_io_poll(void *arg)
 {
 	struct bdev_rbd_io_channel *ch = arg;
@@ -397,7 +399,7 @@ bdev_rbd_io_poll(void *arg)
 
 	/* check the return value of poll since we have only one fd for each channel */
 	if (rc != 1) {
-		return;
+		return 0;
 	}
 
 	rc = rbd_poll_io_events(ch->image, comps, SPDK_RBD_QUEUE_DEPTH);
@@ -432,6 +434,8 @@ bdev_rbd_io_poll(void *arg)
 					      rbd_io->failed ? SPDK_BDEV_IO_STATUS_FAILED : SPDK_BDEV_IO_STATUS_SUCCESS);
 		}
 	}
+
+	return rc;
 }
 
 static void
diff --git a/lib/bdev/virtio/bdev_virtio_blk.c b/lib/bdev/virtio/bdev_virtio_blk.c
index 834d01b2b..aabe423ff 100644
--- a/lib/bdev/virtio/bdev_virtio_blk.c
+++ b/lib/bdev/virtio/bdev_virtio_blk.c
@@ -254,7 +254,7 @@ bdev_virtio_io_cpl(struct spdk_bdev_io *bdev_io)
 			      SPDK_BDEV_IO_STATUS_SUCCESS : SPDK_BDEV_IO_STATUS_FAILED);
 }
 
-static void
+static int
 bdev_virtio_poll(void *arg)
 {
 	struct bdev_virtio_blk_io_channel *ch = arg;
@@ -266,6 +266,8 @@ bdev_virtio_poll(void *arg)
 	for (i = 0; i < cnt; ++i) {
 		bdev_virtio_io_cpl(io[i]);
 	}
+
+	return cnt;
 }
 
 static int
diff --git a/lib/bdev/virtio/bdev_virtio_scsi.c b/lib/bdev/virtio/bdev_virtio_scsi.c
index f5d8d2973..cd0e2eeee 100644
--- a/lib/bdev/virtio/bdev_virtio_scsi.c
+++ b/lib/bdev/virtio/bdev_virtio_scsi.c
@@ -193,7 +193,7 @@ static void virtio_scsi_dev_remove(struct virtio_scsi_dev *svdev,
 static int bdev_virtio_scsi_ch_create_cb(void *io_device, void *ctx_buf);
 static void bdev_virtio_scsi_ch_destroy_cb(void *io_device, void *ctx_buf);
 static void process_scan_resp(struct virtio_scsi_scan_base *base);
-static void bdev_virtio_mgmt_poll(void *arg);
+static int bdev_virtio_mgmt_poll(void *arg);
 
 static int
 virtio_scsi_dev_send_eventq_io(struct virtqueue *vq, struct virtio_scsi_eventq_io *io)
@@ -724,7 +724,7 @@ bdev_virtio_io_cpl(struct spdk_bdev_io *bdev_io)
 	spdk_bdev_io_complete_scsi_status(bdev_io, io_ctx->resp.status, sk, asc, ascq);
 }
 
-static void
+static int
 bdev_virtio_poll(void *arg)
 {
 	struct bdev_virtio_io_channel *ch = arg;
@@ -740,7 +740,7 @@ bdev_virtio_poll(void *arg)
 		if (spdk_unlikely(scan_ctx && io[i] == &scan_ctx->io_ctx)) {
 			if (svdev->removed) {
 				_virtio_scsi_dev_scan_finish(scan_ctx, -EINTR);
-				return;
+				return -1;
 			}
 
 			if (scan_ctx->restart) {
@@ -760,9 +760,9 @@ bdev_virtio_poll(void *arg)
 	if (spdk_unlikely(scan_ctx && scan_ctx->needs_resend)) {
 		if (svdev->removed) {
 			_virtio_scsi_dev_scan_finish(scan_ctx, -EINTR);
-			return;
+			return -1;
 		} else if (cnt == 0) {
-			return;
+			return 0;
 		}
 
 		rc = send_scan_io(scan_ctx);
@@ -775,6 +775,8 @@ bdev_virtio_poll(void *arg)
 			}
 		}
 	}
+
+	return cnt;
 }
 
 static void
@@ -886,7 +888,7 @@ bdev_virtio_send_tmf_io(struct virtqueue *ctrlq, struct spdk_bdev_io *bdev_io)
 	return 0;
 }
 
-static void
+static int
 bdev_virtio_mgmt_poll(void *arg)
 {
 	struct virtio_scsi_dev *svdev = arg;
@@ -898,8 +900,10 @@ bdev_virtio_mgmt_poll(void *arg)
 	uint32_t io_len[16];
 	uint16_t i, cnt;
 	int rc;
+	int total = 0;
 
 	cnt = spdk_ring_dequeue(send_ring, io, SPDK_COUNTOF(io));
+	total += cnt;
 	for (i = 0; i < cnt; ++i) {
 		rc = bdev_virtio_send_tmf_io(ctrlq, io[i]);
 		if (rc != 0) {
@@ -908,14 +912,18 @@ bdev_virtio_mgmt_poll(void *arg)
 	}
 
 	cnt = virtio_recv_pkts(ctrlq, io, io_len, SPDK_COUNTOF(io));
+	total += cnt;
 	for (i = 0; i < cnt; ++i) {
 		bdev_virtio_tmf_cpl(io[i]);
 	}
 
 	cnt = virtio_recv_pkts(eventq, io, io_len, SPDK_COUNTOF(io));
+	total += cnt;
 	for (i = 0; i < cnt; ++i) {
 		bdev_virtio_eventq_io_cpl(svdev, io[i]);
 	}
+
+	return total;
 }
 
 static int
diff --git a/lib/copy/ioat/copy_engine_ioat.c b/lib/copy/ioat/copy_engine_ioat.c
index fd90b5352..4d949fbe2 100644
--- a/lib/copy/ioat/copy_engine_ioat.c
+++ b/lib/copy/ioat/copy_engine_ioat.c
@@ -174,12 +174,14 @@ ioat_copy_submit_fill(void *cb_arg, struct spdk_io_channel *ch, void *dst, uint8
 	return spdk_ioat_submit_fill(ioat_ch->ioat_ch, ioat_task, ioat_done, dst, fill64, nbytes);
 }
 
-static void
+static int
 ioat_poll(void *arg)
 {
 	struct spdk_ioat_chan *chan = arg;
 
 	spdk_ioat_process_events(chan);
+
+	return -1;
 }
 
 static struct spdk_io_channel *ioat_get_io_channel(void);
diff --git a/lib/event/reactor.c b/lib/event/reactor.c
index 92b893525..d792ab2ca 100644
--- a/lib/event/reactor.c
+++ b/lib/event/reactor.c
@@ -316,14 +316,14 @@ _spdk_reactor_stop_poller(struct spdk_poller *poller, void *thread_ctx)
 	}
 }
 
-static void
+static int
 get_rusage(void *arg)
 {
 	struct spdk_reactor	*reactor = arg;
 	struct rusage		rusage;
 
 	if (getrusage(RUSAGE_THREAD, &rusage) != 0) {
-		return;
+		return -1;
 	}
 
 	if (rusage.ru_nvcsw != reactor->rusage.ru_nvcsw || rusage.ru_nivcsw != reactor->rusage.ru_nivcsw) {
@@ -333,6 +333,8 @@ get_rusage(void *arg)
 			     rusage.ru_nivcsw - reactor->rusage.ru_nivcsw);
 	}
 	reactor->rusage = rusage;
+
+	return -1;
 }
 
 static void
diff --git a/lib/event/rpc.c b/lib/event/rpc.c
index 9f7d7ab57..1e2f75b88 100644
--- a/lib/event/rpc.c
+++ b/lib/event/rpc.c
@@ -45,10 +45,11 @@
 
 static struct spdk_poller *g_rpc_poller = NULL;
 
-static void
+static int
 spdk_rpc_subsystem_poll(void *arg)
 {
 	spdk_rpc_accept();
+	return -1;
 }
 
 void
diff --git a/lib/event/subsystems/nvmf/nvmf_tgt.c b/lib/event/subsystems/nvmf/nvmf_tgt.c
index 9d145a8aa..85a81404a 100644
--- a/lib/event/subsystems/nvmf/nvmf_tgt.c
+++ b/lib/event/subsystems/nvmf/nvmf_tgt.c
@@ -133,12 +133,14 @@ new_qpair(struct spdk_nvmf_qpair *qpair)
 	spdk_event_call(event);
 }
 
-static void
+static int
 acceptor_poll(void *arg)
 {
 	struct spdk_nvmf_tgt *tgt = arg;
 
 	spdk_nvmf_tgt_accept(tgt, new_qpair);
+
+	return -1;
 }
 
 static void
diff --git a/lib/iscsi/acceptor.c b/lib/iscsi/acceptor.c
index 79d2c74ba..2b7e64fae 100644
--- a/lib/iscsi/acceptor.c
+++ b/lib/iscsi/acceptor.c
@@ -45,15 +45,16 @@
 
 #define ACCEPT_TIMEOUT_US 1000 /* 1ms */
 
-static void
+static int
 spdk_iscsi_portal_accept(void *arg)
 {
 	struct spdk_iscsi_portal	*portal = arg;
 	struct spdk_sock		*sock;
 	int				rc;
+	int				count = 0;
 
 	if (portal->sock == NULL) {
-		return;
+		return -1;
 	}
 
 	while (1) {
@@ -65,6 +66,7 @@ spdk_iscsi_portal_accept(void *arg)
 				SPDK_ERRLOG("spdk_iscsi_connection_construct() failed\n");
 				break;
 			}
+			count++;
 		} else {
 			if (errno != EAGAIN && errno != EWOULDBLOCK) {
 				SPDK_ERRLOG("accept error(%d): %s\n", errno, spdk_strerror(errno));
@@ -72,6 +74,8 @@ spdk_iscsi_portal_accept(void *arg)
 			break;
 		}
 	}
+
+	return count;
 }
 
 void
diff --git a/lib/iscsi/conn.c b/lib/iscsi/conn.c
index a72010b7a..d8a64c17d 100644
--- a/lib/iscsi/conn.c
+++ b/lib/iscsi/conn.c
@@ -493,7 +493,7 @@ _spdk_iscsi_conn_free(struct spdk_iscsi_conn *conn)
 	pthread_mutex_unlock(&g_conns_mutex);
 }
 
-static void
+static int
 _spdk_iscsi_conn_check_shutdown(void *arg)
 {
 	struct spdk_iscsi_conn *conn = arg;
@@ -501,13 +501,15 @@ _spdk_iscsi_conn_check_shutdown(void *arg)
 
 	rc = spdk_iscsi_conn_free_tasks(conn);
 	if (rc < 0) {
-		return;
+		return -1;
 	}
 
 	spdk_poller_unregister(&conn->shutdown_timer);
 
 	spdk_iscsi_conn_stop(conn);
 	_spdk_iscsi_conn_free(conn);
+
+	return -1;
 }
 
 void
@@ -576,7 +578,7 @@ spdk_iscsi_conn_check_shutdown_cb(void *arg1, void *arg2)
 	spdk_shutdown_iscsi_conns_done();
 }
 
-static void
+static int
 spdk_iscsi_conn_check_shutdown(void *arg)
 {
 	struct spdk_event *event;
@@ -587,6 +589,8 @@ spdk_iscsi_conn_check_shutdown(void *arg)
 					    NULL);
 		spdk_event_call(event);
 	}
+
+	return -1;
 }
 
 /**
@@ -1064,7 +1068,7 @@ spdk_iscsi_conn_flush_pdus_internal(struct spdk_iscsi_conn *conn)
  * Returns -1 for an exceptional error indicating the TCP connection
  * should be closed.
  */
-static void
+static int
 spdk_iscsi_conn_flush_pdus(void *_conn)
 {
 	struct spdk_iscsi_conn *conn = _conn;
@@ -1097,6 +1101,8 @@ spdk_iscsi_conn_flush_pdus(void *_conn)
 		 */
 		conn->state = ISCSI_CONN_STATE_EXITING;
 	}
+
+	return -1;
 }
 
 void
@@ -1265,12 +1271,14 @@ spdk_iscsi_conn_allocate_reactor(const struct spdk_cpuset *cpumask)
 	return selected_core;
 }
 
-static void
+static int
 logout_timeout(void *arg)
 {
 	struct spdk_iscsi_conn *conn = arg;
 
 	spdk_iscsi_conn_destruct(conn);
+
+	return -1;
 }
 
 void
diff --git a/lib/iscsi/iscsi_subsystem.c b/lib/iscsi/iscsi_subsystem.c
index 22e5c9216..5eb64f604 100644
--- a/lib/iscsi/iscsi_subsystem.c
+++ b/lib/iscsi/iscsi_subsystem.c
@@ -855,7 +855,7 @@ spdk_iscsi_init_complete(int rc)
 	cb_fn(cb_arg, rc);
 }
 
-static void
+static int
 spdk_iscsi_poll_group_poll(void *ctx)
 {
 	struct spdk_iscsi_poll_group *group = ctx;
@@ -874,9 +874,11 @@ spdk_iscsi_poll_group_poll(void *ctx)
 			spdk_iscsi_conn_destruct(conn);
 		}
 	}
+
+	return -1;
 }
 
-static void
+static int
 spdk_iscsi_poll_group_handle_nop(void *ctx)
 {
 	struct spdk_iscsi_poll_group *group = ctx;
@@ -885,6 +887,8 @@ spdk_iscsi_poll_group_handle_nop(void *ctx)
 	STAILQ_FOREACH_SAFE(conn, &group->connections, link, tmp) {
 		spdk_iscsi_conn_handle_nop(conn);
 	}
+
+	return -1;
 }
 
 static void
diff --git a/lib/nbd/nbd.c b/lib/nbd/nbd.c
index 470ab55a9..48a3e0173 100644
--- a/lib/nbd/nbd.c
+++ b/lib/nbd/nbd.c
@@ -726,7 +726,7 @@ _spdk_nbd_poll(struct spdk_nbd_disk *nbd)
 	return rc;
 }
 
-static void
+static int
 spdk_nbd_poll(void *arg)
 {
 	struct spdk_nbd_disk *nbd = arg;
@@ -738,6 +738,8 @@ spdk_nbd_poll(void *arg)
 			     spdk_strerror(-rc), rc);
 		spdk_nbd_stop(nbd);
 	}
+
+	return -1;
 }
 
 static void *
diff --git a/lib/nvmf/nvmf.c b/lib/nvmf/nvmf.c
index 009557e23..f8cc8d52a 100644
--- a/lib/nvmf/nvmf.c
+++ b/lib/nvmf/nvmf.c
@@ -62,19 +62,23 @@ spdk_nvmf_tgt_opts_init(struct spdk_nvmf_tgt_opts *opts)
 	opts->max_io_size = SPDK_NVMF_DEFAULT_MAX_IO_SIZE;
 }
 
-static void
+static int
 spdk_nvmf_poll_group_poll(void *ctx)
 {
 	struct spdk_nvmf_poll_group *group = ctx;
 	int rc;
+	int count = 0;
 	struct spdk_nvmf_transport_poll_group *tgroup;
 
 	TAILQ_FOREACH(tgroup, &group->tgroups, link) {
 		rc = spdk_nvmf_transport_poll_group_poll(tgroup);
 		if (rc < 0) {
-			return;
+			return -1;
 		}
+		count += rc;
 	}
+
+	return count;
 }
 
 static int
diff --git a/lib/scsi/lun.c b/lib/scsi/lun.c
index a125f4db9..679959141 100644
--- a/lib/scsi/lun.c
+++ b/lib/scsi/lun.c
@@ -181,7 +181,7 @@ spdk_scsi_lun_execute_task(struct spdk_scsi_lun *lun, struct spdk_scsi_task *tas
 	}
 }
 
-static void
+static int
 spdk_scsi_lun_hotplug(void *arg)
 {
 	struct spdk_scsi_lun *lun = (struct spdk_scsi_lun *)arg;
@@ -195,6 +195,8 @@ spdk_scsi_lun_hotplug(void *arg)
 		spdk_scsi_dev_delete_lun(lun->dev, lun);
 		free(lun);
 	}
+
+	return -1;
 }
 
 static void
diff --git a/lib/vhost/vhost_blk.c b/lib/vhost/vhost_blk.c
index 1cef98ccf..bebd3d4c7 100644
--- a/lib/vhost/vhost_blk.c
+++ b/lib/vhost/vhost_blk.c
@@ -327,7 +327,7 @@ process_vq(struct spdk_vhost_blk_dev *bvdev, struct spdk_vhost_virtqueue *vq)
 	}
 }
 
-static void
+static int
 vdev_worker(void *arg)
 {
 	struct spdk_vhost_blk_dev *bvdev = arg;
@@ -338,6 +338,8 @@ vdev_worker(void *arg)
 	}
 
 	spdk_vhost_dev_used_signal(&bvdev->vdev);
+
+	return -1;
 }
 
 static void
@@ -360,7 +362,7 @@ no_bdev_process_vq(struct spdk_vhost_blk_dev *bvdev, struct spdk_vhost_virtqueue
 	spdk_vhost_vq_used_ring_enqueue(&bvdev->vdev, vq, req_idx, 0);
 }
 
-static void
+static int
 no_bdev_vdev_worker(void *arg)
 {
 	struct spdk_vhost_blk_dev *bvdev = arg;
@@ -371,6 +373,8 @@ no_bdev_vdev_worker(void *arg)
 	}
 
 	spdk_vhost_dev_used_signal(&bvdev->vdev);
+
+	return -1;
 }
 
 static struct spdk_vhost_blk_dev *
@@ -528,7 +532,7 @@ struct spdk_vhost_dev_destroy_ctx {
 	void *event_ctx;
 };
 
-static void
+static int
 destroy_device_poller_cb(void *arg)
 {
 	struct spdk_vhost_dev_destroy_ctx *ctx = arg;
@@ -536,7 +540,7 @@ destroy_device_poller_cb(void *arg)
 	int i;
 
 	if (bvdev->vdev.task_cnt > 0) {
-		return;
+		return -1;
 	}
 
 	for (i = 0; i < bvdev->vdev.num_queues; i++) {
@@ -557,6 +561,8 @@ destroy_device_poller_cb(void *arg)
 	spdk_poller_unregister(&ctx->poller);
 	spdk_vhost_dev_backend_event_done(ctx->event_ctx, 0);
 	spdk_dma_free(ctx);
+
+	return -1;
 }
 
 static int
diff --git a/lib/vhost/vhost_scsi.c b/lib/vhost/vhost_scsi.c
index 26544f55b..3adc55f66 100644
--- a/lib/vhost/vhost_scsi.c
+++ b/lib/vhost/vhost_scsi.c
@@ -645,7 +645,7 @@ process_requestq(struct spdk_vhost_scsi_dev *svdev, struct spdk_vhost_virtqueue
 	}
 }
 
-static void
+static int
 vdev_mgmt_worker(void *arg)
 {
 	struct spdk_vhost_scsi_dev *svdev = arg;
@@ -655,9 +655,11 @@ vdev_mgmt_worker(void *arg)
 
 	process_controlq(svdev, &svdev->vdev.virtqueue[VIRTIO_SCSI_CONTROLQ]);
 	spdk_vhost_vq_used_signal(&svdev->vdev, &svdev->vdev.virtqueue[VIRTIO_SCSI_CONTROLQ]);
+
+	return -1;
 }
 
-static void
+static int
 vdev_worker(void *arg)
 {
 	struct spdk_vhost_scsi_dev *svdev = arg;
@@ -668,6 +670,8 @@ vdev_worker(void *arg)
 	}
 
 	spdk_vhost_dev_used_signal(&svdev->vdev);
+
+	return -1;
 }
 
 static struct spdk_vhost_scsi_dev *
@@ -1094,7 +1098,7 @@ struct spdk_vhost_dev_destroy_ctx {
 	void *event_ctx;
 };
 
-static void
+static int
 destroy_device_poller_cb(void *arg)
 {
 	struct spdk_vhost_dev_destroy_ctx *ctx = arg;
@@ -1102,7 +1106,7 @@ destroy_device_poller_cb(void *arg)
 	uint32_t i;
 
 	if (svdev->vdev.task_cnt > 0) {
-		return;
+		return -1;
 	}
 
 
@@ -1125,6 +1129,8 @@ destroy_device_poller_cb(void *arg)
 	spdk_poller_unregister(&ctx->poller);
 	spdk_vhost_dev_backend_event_done(ctx->event_ctx, 0);
 	spdk_dma_free(ctx);
+
+	return -1;
 }
 
 static int
diff --git a/test/lib/bdev/bdevperf/bdevperf.c b/test/lib/bdev/bdevperf/bdevperf.c
index 81755961d..d2d53d137 100644
--- a/test/lib/bdev/bdevperf/bdevperf.c
+++ b/test/lib/bdev/bdevperf/bdevperf.c
@@ -468,7 +468,7 @@ bdevperf_submit_io(struct io_target *target, int queue_depth)
 	}
 }
 
-static void
+static int
 end_target(void *arg)
 {
 	struct io_target *target = arg;
@@ -479,9 +479,11 @@ end_target(void *arg)
 	}
 
 	target->is_draining = true;
+
+	return -1;
 }
 
-static void reset_target(void *arg);
+static int reset_target(void *arg);
 
 static void
 reset_cb(struct spdk_bdev_io *bdev_io, bool success, void *cb_arg)
@@ -502,7 +504,7 @@ reset_cb(struct spdk_bdev_io *bdev_io, bool success, void *cb_arg)
 			      10 * 1000000);
 }
 
-static void
+static int
 reset_target(void *arg)
 {
 	struct io_target *target = arg;
@@ -526,6 +528,8 @@ reset_target(void *arg)
 		target->is_draining = true;
 		g_run_failed = true;
 	}
+
+	return -1;
 }
 
 static void
@@ -647,12 +651,13 @@ performance_dump(uint64_t io_time_in_usec, uint64_t ema_period)
 
 }
 
-static void
+static int
 performance_statistics_thread(void *arg)
 {
 	g_show_performance_period_num++;
 	performance_dump(g_show_performance_period_num * g_show_performance_period_in_usec,
 			 g_show_performance_ema_period);
+	return -1;
 }
 
 static int
diff --git a/test/lib/event/reactor/reactor.c b/test/lib/event/reactor/reactor.c
index 7904fd1b1..bd94303c9 100644
--- a/test/lib/event/reactor/reactor.c
+++ b/test/lib/event/reactor/reactor.c
@@ -44,7 +44,7 @@ static struct spdk_poller *poller_500ms;
 static struct spdk_poller *poller_oneshot;
 static struct spdk_poller *poller_unregister;
 
-static void
+static int
 test_end(void *arg)
 {
 	printf("test_end\n");
@@ -55,26 +55,32 @@ test_end(void *arg)
 	spdk_poller_unregister(&poller_500ms);
 
 	spdk_app_stop(0);
+	return -1;
 }
 
-static void
+static int
 tick(void *arg)
 {
 	uintptr_t period = (uintptr_t)arg;
 
 	printf("tick %" PRIu64 "\n", (uint64_t)period);
+
+	return -1;
 }
 
-static void
+static int
 oneshot(void *arg)
 {
 	printf("oneshot\n");
 	spdk_poller_unregister(&poller_oneshot);
+
+	return -1;
 }
 
-static void
+static int
 nop(void *arg)
 {
+	return -1;
 }
 
 static void
diff --git a/test/lib/event/reactor_perf/reactor_perf.c b/test/lib/event/reactor_perf/reactor_perf.c
index 1a57c7dd5..df9680988 100644
--- a/test/lib/event/reactor_perf/reactor_perf.c
+++ b/test/lib/event/reactor_perf/reactor_perf.c
@@ -42,11 +42,12 @@ static int g_queue_depth;
 static struct spdk_poller *test_end_poller;
 static uint64_t g_call_count = 0;
 
-static void
+static int
 __test_end(void *arg)
 {
 	printf("test_end\n");
 	spdk_app_stop(0);
+	return -1;
 }
 
 static void
diff --git a/test/unit/lib/bdev/mt/bdev.c/bdev_ut.c b/test/unit/lib/bdev/mt/bdev.c/bdev_ut.c
index 1a60e68a5..3afa2ce4b 100644
--- a/test/unit/lib/bdev/mt/bdev.c/bdev_ut.c
+++ b/test/unit/lib/bdev/mt/bdev.c/bdev_ut.c
@@ -288,20 +288,24 @@ basic(void)
 	teardown_test();
 }
 
-static void
+static int
 poller_run_done(void *ctx)
 {
 	bool	*poller_run = ctx;
 
 	*poller_run = true;
+
+	return -1;
 }
 
-static void
+static int
 poller_run_times_done(void *ctx)
 {
 	int	*poller_run_times = ctx;
 
 	(*poller_run_times)++;
+
+	return -1;
 }
 
 static void