diff --git a/include/maxscale/poll_core.h b/include/maxscale/poll_core.h
index 1563f37f3..6372b1fd4 100644
--- a/include/maxscale/poll_core.h
+++ b/include/maxscale/poll_core.h
@@ -83,9 +83,9 @@ typedef struct mxs_poll_data
  *
  * @attention The provided file descriptor *must* be non-blocking.
  *
- * @return 0 on success, non-zero on failure.
+ * @return True on success, false on failure.
  */
-int poll_add_fd_to_worker(int wid, int fd, uint32_t events, MXS_POLL_DATA* data);
+bool poll_add_fd_to_worker(int wid, int fd, uint32_t events, MXS_POLL_DATA* data);
 
 
 /**
@@ -95,8 +95,8 @@ int poll_add_fd_to_worker(int wid, int fd, uint32_t events, MXS_POLL_DATA* data)
  *                 the poll set of all workers; otherwise the id of a worker.
  * @param fd       The file descriptor to be removed.
  *
- * @return 0 on success, non-zero on failure.
+ * @return True on success, false on failure.
  */
-int poll_remove_fd_from_worker(int wid, int fd);
+bool poll_remove_fd_from_worker(int wid, int fd);
 
 MXS_END_DECLS
diff --git a/server/core/dcb.cc b/server/core/dcb.cc
index 94cef3530..a57fbd86a 100644
--- a/server/core/dcb.cc
+++ b/server/core/dcb.cc
@@ -3607,9 +3607,7 @@ int poll_add_dcb(DCB *dcb)
         worker_id = MXS_WORKER_ANY;
     }
 
-    rc = poll_add_fd_to_worker(worker_id, dcb->fd, events, (MXS_POLL_DATA*)dcb);
-
-    if (0 == rc)
+    if (poll_add_fd_to_worker(worker_id, dcb->fd, events, (MXS_POLL_DATA*)dcb))
     {
         dcb_add_to_list(dcb);
 
@@ -3617,10 +3615,12 @@ int poll_add_dcb(DCB *dcb)
                   pthread_self(),
                   dcb,
                   STRDCBSTATE(dcb->state));
+        rc = 0;
     }
     else
     {
         dcb->state = old_state;
+        rc = -1;
     }
     return rc;
 }
@@ -3673,7 +3673,14 @@ int poll_remove_dcb(DCB *dcb)
             worker_id = dcb->poll.thread.id;
         }
 
-        rc = poll_remove_fd_from_worker(worker_id, dcbfd);
+        if (poll_remove_fd_from_worker(worker_id, dcbfd))
+        {
+            rc = 0;
+        }
+        else
+        {
+            rc = -1;
+        }
     }
     return rc;
 }
diff --git a/server/core/poll.cc b/server/core/poll.cc
index 72f0db2d9..0e4036fd4 100644
--- a/server/core/poll.cc
+++ b/server/core/poll.cc
@@ -289,7 +289,7 @@ poll_init()
     max_poll_sleep = config_pollsleep();
 }
 
-static int add_fd_to_worker(int wid, int fd, uint32_t events, MXS_POLL_DATA* data)
+static bool add_fd_to_worker(int wid, int fd, uint32_t events, MXS_POLL_DATA* data)
 {
     ss_dassert((wid >= 0) && (wid <= n_threads));
 
@@ -308,10 +308,10 @@ static int add_fd_to_worker(int wid, int fd, uint32_t events, MXS_POLL_DATA* dat
         rc = poll_resolve_error(fd, errno, EPOLL_CTL_ADD);
     }
 
-    return rc;
+    return rc == 0;
 }
 
-static int add_fd_to_workers(int fd, uint32_t events, MXS_POLL_DATA* data)
+static bool add_fd_to_workers(int fd, uint32_t events, MXS_POLL_DATA* data)
 {
     events |= EPOLLET;
 
@@ -345,42 +345,34 @@ static int add_fd_to_workers(int fd, uint32_t events, MXS_POLL_DATA* data)
         rc = poll_resolve_error(fd, stored_errno, EPOLL_CTL_ADD);
     }
 
-    return rc;
+    return rc == 0;
 }
 
-int poll_add_fd_to_worker(int wid, int fd, uint32_t events, MXS_POLL_DATA* data)
+bool poll_add_fd_to_worker(int wid, int fd, uint32_t events, MXS_POLL_DATA* data)
 {
-    int rc;
+    bool rv;
 
     if (wid == MXS_WORKER_ANY)
     {
         wid = (int)atomic_add(&next_epoll_fd, 1) % n_threads;
 
-        rc = add_fd_to_worker(wid, fd, events, data);
+        rv = add_fd_to_worker(wid, fd, events, data);
     }
     else if (wid == MXS_WORKER_ALL)
     {
-        rc = add_fd_to_workers(fd, events, data);
+        rv = add_fd_to_workers(fd, events, data);
     }
     else
     {
         ss_dassert((wid >= 0) && (wid < n_threads));
 
-        if ((wid >= 0) && (wid < n_threads))
-        {
-            rc = add_fd_to_worker(wid, fd, events, data);
-        }
-        else
-        {
-            errno = EINVAL;
-            rc = -1;
-        }
+        rv = add_fd_to_worker(wid, fd, events, data);
     }
 
-    return rc;
+    return rv;
 }
 
-static int remove_fd_from_worker(int wid, int fd)
+static bool remove_fd_from_worker(int wid, int fd)
 {
     ss_dassert((wid >= 0) && (wid < n_threads));
 
@@ -393,10 +385,10 @@ static int remove_fd_from_worker(int wid, int fd)
         rc = poll_resolve_error(fd, errno, EPOLL_CTL_DEL);
     }
 
-    return rc;
+    return rc == 0;
 }
 
-static int remove_fd_from_workers(int fd)
+static bool remove_fd_from_workers(int fd)
 {
     int rc;
 
@@ -407,23 +399,23 @@ static int remove_fd_from_workers(int fd)
         remove_fd_from_worker(i, fd);
     }
 
-    return 0;
+    return true;
 }
 
-int poll_remove_fd_from_worker(int wid, int fd)
+bool poll_remove_fd_from_worker(int wid, int fd)
 {
-    int rc;
+    bool rv;
 
     if (wid == MXS_WORKER_ALL)
     {
-        rc = remove_fd_from_workers(fd);
+        rv = remove_fd_from_workers(fd);
     }
     else
     {
-        rc = remove_fd_from_worker(wid, fd);
+        rv = remove_fd_from_worker(wid, fd);
     }
 
-    return rc;
+    return rv;
 }
 
 /**
diff --git a/server/core/worker.cc b/server/core/worker.cc
index 747148f48..622c1281d 100644
--- a/server/core/worker.cc
+++ b/server/core/worker.cc
@@ -400,7 +400,7 @@ Worker* Worker::create(int worker_id)
 
             if (pWorker)
             {
-                if (poll_add_fd_to_worker(worker_id, read_fd, EPOLLIN, &pWorker->m_poll) != 0)
+                if (!poll_add_fd_to_worker(worker_id, read_fd, EPOLLIN, &pWorker->m_poll))
                 {
                     MXS_ERROR("Could not add read descriptor of worker to poll set: %s", mxs_strerror(errno));
                     delete pWorker;